diff --git a/app/src/App.css b/app/src/App.css
index 50bbb637..7dee8bee 100644
--- a/app/src/App.css
+++ b/app/src/App.css
@@ -1,3 +1,47 @@
+/* Nav bar: a hand-rolled flexbox bar (was a Semantic Menu).  The user-chosen
+   background color and the `--btn-text` foreground are set inline per theme;
+   this stylesheet only supplies structure and hover affordances. */
+.wrolpi-navbar {
+    display: flex;
+    align-items: stretch;
+    /*
+     * Wraps rather than clipping.  Semantic's menu wrapped, and with this many items the
+     * bar overflows a 1000px viewport -- `nowrap` cut "Admin" off the right edge, which
+     * is the one link a user needs to reach the settings that fix a broken WROLPi.
+     */
+    flex-wrap: wrap;
+    min-height: 3.4em;
+    padding: 0 0.25em;
+}
+
+.wrolpi-navbar-right {
+    display: flex;
+    align-items: center;
+    margin-left: auto;
+    gap: 0.2em;
+}
+
+.wrolpi-navbar-link,
+.wrolpi-navbar-link-button {
+    display: flex;
+    align-items: center;
+    /* Tightened from 1.1em: the bar has eleven links plus nine indicators. */
+    padding: 0 0.8em;
+    color: inherit;
+    text-decoration: none;
+    white-space: nowrap;
+    background: none;
+    border: none;
+    font: inherit;
+    cursor: pointer;
+}
+
+.wrolpi-navbar-link:hover,
+.wrolpi-navbar-link-button:hover {
+    /* A translucent black works on every navbar colour, light or dark. */
+    background: rgba(0, 0, 0, 0.12);
+}
+
 .channel-edit {
     border-radius: 3px;
     padding: 0.75em;
diff --git a/app/src/App.js b/app/src/App.js
index 68d69f8a..1e372a53 100644
--- a/app/src/App.js
+++ b/app/src/App.js
@@ -5,7 +5,6 @@ import {createBrowserRouter, createRoutesFromElements, Link, Outlet, Route, Rout
 import {VideosTabLayout, VideosPage, VideosSettingsPage, VideosStatistics, VideoWrapper} from "./components/Videos";
 import AdminRoute from "./components/admin/AdminRoute";
 import {Box, Header} from "./components/ui";
-import 'semantic-ui-offline/semantic.min.css';
 import '@mantine/core/styles.css';
 import '@mantine/notifications/styles.css';
 // Theme tokens load last so they win over both component libraries.
diff --git a/app/src/components/Archive.js b/app/src/components/Archive.js
index 78470c7c..a8d97418 100644
--- a/app/src/components/Archive.js
+++ b/app/src/components/Archive.js
@@ -1,24 +1,5 @@
-import React, {useContext, useState} from "react";
+import React, {useState} from "react";
 import {useHotkeys} from "react-hotkeys-hook";
-import {
-    CardContent,
-    CardDescription,
-    CardHeader,
-    CardMeta,
-    Container,
-    Form,
-    GridColumn,
-    GridRow,
-    Image,
-    Input,
-    PlaceholderHeader,
-    PlaceholderLine,
-    StatisticLabel,
-    StatisticValue,
-    TableCell,
-    TextArea,
-} from "semantic-ui-react";
-import Icon from "semantic-ui-react/dist/commonjs/elements/Icon";
 import {
     APIButton,
     BackButton,
@@ -33,14 +14,14 @@ import {
     humanNumber,
     InfoHeader,
     isoDatetimeToAgoPopup,
-    mimetypeColor,
     PageContainer,
     PreviewPath,
     resolveDataPath,
     SearchInput,
     TabLinks,
     textEllipsis,
-    useTitle
+    mimetypeColor,
+    useTitle,
 } from "./Common";
 import {
     deleteDomain,
@@ -58,14 +39,13 @@ import {
     untagFileGroup,
     updateArchiveDownloaderConfig,
 } from "../api";
-import {InputForm, useForm} from "../hooks/useForm";
+import {useForm} from "../hooks/useForm";
 import {TaggedDeleteConfirmModal} from "./TaggedDeleteConfirmModal";
 import {CollectionTagModal} from "./collections/CollectionTagModal";
 import {CollectionReorganizeModal} from "./collections/CollectionReorganizeModal";
 import {BatchReorganizeModal} from "./collections/BatchReorganizeModal";
 import {useReorganizationStatus} from "../contexts/FileWorkerStatusContext";
 import {Link, Route, Routes, useLocation, useNavigate, useParams} from "react-router";
-import Message from "semantic-ui-react/dist/commonjs/collections/Message";
 import {
     useArchive,
     useArchiveStatistics,
@@ -78,14 +58,32 @@ import {
     useSearchOrder
 } from "../hooks/customHooks";
 import {DeepSearchHint, FileCards, FileRowTagIcon, FilesView, SearchControlBar} from "./Files";
-import Grid from "semantic-ui-react/dist/commonjs/collections/Grid";
 import _ from "lodash";
-import {ThemeContext} from "../contexts/contexts";
-import {Button, Card, darkTheme, Header, Loader, Placeholder, Popup, Segment, Statistic, Tab} from "./Theme";
+import {
+    ActionInput,
+    Button,
+    Card,
+    Header,
+    Icon,
+    IconButton,
+    Loader,
+    Loading,
+    Message,
+    Panel,
+    Placeholder,
+    Select,
+    Statistic,
+    StatisticGroup,
+    Table,
+    Tabs,
+    Textarea,
+    TextInput,
+    Tooltip,
+    toast,
+} from "./ui";
 import {BulkTagModal} from "./BulkTagModal";
-import {taggedImageLabel, TagsSelector} from "../Tags";
+import {TagsSelector} from "../Tags";
 import {AddToPlaylistButton} from "./AddToPlaylist";
-import {toast} from "./ui";
 import {API_ARCHIVE_UPLOAD_URI, Downloaders} from "./Vars";
 import {CollectionTable} from "./collections/CollectionTable";
 import {CollectionEditForm} from "./collections/CollectionEditForm";
@@ -96,14 +94,13 @@ function ArchivePage() {
     const navigate = useNavigate();
     const {fileGroupId} = useParams();
     const {archiveFile, history, fetchArchive} = useArchive(fileGroupId);
-    const {theme} = useContext(ThemeContext);
     const [taggedFileGroups, setTaggedFileGroups] = useState(null);
 
     let title = archiveFile ? archiveFile.title ? archiveFile.title : archiveFile.name : null;
     useTitle(title);
 
     if (archiveFile === null) {
-        return <Segment><Loader active/></Segment>;
+        return <Panel><Loading>Loading archive...</Loading></Panel>;
     }
     if (archiveFile === undefined) {
         return <>
@@ -124,14 +121,15 @@ function ArchivePage() {
     const screenshotUrl = screenshotPath ? `/media/${encodeMediaPath(screenshotPath)}` : null;
 
     const singlefileButton = <ExternalCardLink to={singlefileUrl}>
-        <Button content='View' color='violet'/>
+        <Button color='violet'>View</Button>
     </ExternalCardLink>;
     const readButton = <ExternalCardLink to={readabilityUrl}>
-        <Button content='Read' color='blue' disabled={!!!readabilityUrl}/>
+        <Button color='blue' disabled={!!!readabilityUrl}>Read</Button>
     </ExternalCardLink>
 
     const screenshot = screenshotUrl ?
-        <Image src={screenshotUrl} size='large' style={{marginTop: '1em', marginBottom: '1em'}}/> :
+        <img alt='Archive screenshot' src={screenshotUrl}
+             style={{marginTop: '1em', marginBottom: '1em', maxWidth: '100%'}}/> :
         null;
 
     const localDeleteArchive = async (force = false) => {
@@ -171,7 +169,6 @@ function ArchivePage() {
     }
 
     const updateButton = <APIButton
-        text='Update'
         color='green'
         confirmContent='Download the latest version of this URL?'
         confirmButton='Update'
@@ -182,17 +179,15 @@ function ArchivePage() {
         Update
     </APIButton>;
     const deleteButton = <APIButton
-        text='Delete'
-        color='red'
+        role='danger'
         confirmContent='Are you sure you want to delete this archive? All files will be deleted'
-        confirmButton='Delete'
+        confirmButton='Delete Archive'
         onClick={() => localDeleteArchive(false)}
         obeyWROLMode={true}
     >
         Delete
     </APIButton>;
     const generateScreenshotButton = !screenshotUrl ? <APIButton
-        text='Generate Screenshot'
         color='yellow'
         confirmContent='Generate a screenshot for this archive?'
         confirmButton='Generate'
@@ -203,7 +198,7 @@ function ArchivePage() {
         Generate Screenshot
     </APIButton> : null;
 
-    let historyList = <Loader active/>;
+    let historyList = <Loader/>;
     if (history && history.length === 0) {
         historyList = <p>No history available</p>;
     } else if (history) {
@@ -237,28 +232,12 @@ function ArchivePage() {
         ? isoDatetimeToAgoPopup(archiveFile.published_modified_datetime, true)
         : 'unknown';
 
-    const aboutPane = {
-        menuItem: 'About', render: () => <Tab.Pane>
-            <Header as={'h3'}>Domain</Header>
-            {domainHeader}
-
-            <Header as='h3'>Size</Header>
-            {humanFileSize(size)}
-
-            <Header as={'h3'}>URL</Header>
-            <p>{archiveFile.url ? <a href={archiveFile.url}>{archiveFile.url}</a> : 'N/A'}</p>
-
-            <Header as={'h3'}>Modified Date</Header>
-            <p>{modifiedDatetimeString}</p>
-        </Tab.Pane>
-    };
-
     // Helper to find file size from the files array by resolved path
     const findFileSize = (resolvedPath) => {
         if (!resolvedPath || !archiveFile.files) return null;
         const file = archiveFile.files.find(i => String(i.path) === String(resolvedPath));
         return file && file.size
-            ? <span style={{marginLeft: '1em', color: 'grey'}}>({humanFileSize(file.size)})</span>
+            ? <span style={{marginLeft: '1em', color: 'var(--muted)'}}>({humanFileSize(file.size)})</span>
             : null;
     };
 
@@ -275,51 +254,11 @@ function ArchivePage() {
 
     const tableStyle = {width: '100%', borderCollapse: 'separate', borderSpacing: '0 0.7em'};
     const labelStyle = {whiteSpace: 'nowrap', paddingRight: '1.5em', verticalAlign: 'top'};
-    const filesPane = {
-        menuItem: 'Files', render: () => <Tab.Pane>
-            <table style={tableStyle}>
-                <tbody>
-                <tr>
-                    <td style={labelStyle}><strong>Singlefile File</strong></td>
-                    <td>{localPreviewPath(data.singlefile_path, 'text/html')}</td>
-                </tr>
-                <tr>
-                    <td style={labelStyle}><strong>Readability File</strong></td>
-                    <td>{localPreviewPath(data.readability_path, 'text/html')}</td>
-                </tr>
-                <tr>
-                    <td style={labelStyle}><strong>Readability Text File</strong></td>
-                    <td>{localPreviewPath(data.readability_txt_path, 'text/plain')}</td>
-                </tr>
-                <tr>
-                    <td style={labelStyle}><strong>Readability JSON File</strong></td>
-                    <td>{localPreviewPath(data.readability_json_path, 'application/json')}</td>
-                </tr>
-                <tr>
-                    <td style={labelStyle}><strong>Screenshot File</strong></td>
-                    <td>
-                        {screenshotPath
-                            ? <><PreviewPath path={screenshotPath} mimetype='image/*'
-                                             taggable={false}>{screenshotPath}</PreviewPath>{findFileSize(screenshotPath)}</>
-                            : 'Unknown'}
-                    </td>
-                </tr>
-                <tr>
-                    <td style={labelStyle}><strong>Directory</strong></td>
-                    <td><DirectoryLink path={archiveFile.directory}/></td>
-                </tr>
-                </tbody>
-            </table>
-        </Tab.Pane>
-    };
-
-    const tabPanes = [aboutPane, filesPane];
-    const tabMenu = theme === darkTheme ? {inverted: true, attached: true} : {attached: true};
 
     return <>
         <BackButton/>
 
-        <Segment>
+        <Panel>
             {screenshot}
             <ExternalCardLink to={singlefileUrl}>
                 <Header as='h2'>{textEllipsis(archiveFile.title || data.url)}</Header>
@@ -327,16 +266,14 @@ function ArchivePage() {
 
             <Header as='h3'>Author: {archiveFile.author ? archiveFile.author : 'unknown'}</Header>
 
-            <Grid columns={2} stackable>
-                <GridRow>
-                    <GridColumn>
-                        <Header as='h4'>Published: {publishedDatetimeString}</Header>
-                    </GridColumn>
-                    <GridColumn>
-                        <Header as='h4'>Downloaded: {downloadDatetimeString}</Header>
-                    </GridColumn>
-                </GridRow>
-            </Grid>
+            <div style={{display: 'flex', flexWrap: 'wrap', gap: '1em', marginBottom: '1em'}}>
+                <div style={{flex: '1 1 240px'}}>
+                    <Header as='h4'>Published: {publishedDatetimeString}</Header>
+                </div>
+                <div style={{flex: '1 1 240px'}}>
+                    <Header as='h4'>Downloaded: {downloadDatetimeString}</Header>
+                </div>
+            </div>
 
             {singlefileButton}
             {readButton}
@@ -344,25 +281,78 @@ function ArchivePage() {
             {deleteButton}
             {generateScreenshotButton}
             <AddToPlaylistButton fileGroupId={archiveFile.id}/>
-        </Segment>
+        </Panel>
 
-        <Segment>
+        <Panel>
             <TagsSelector
                 selectedTagNames={archiveFile['tags']}
                 onAdd={localAddTag}
                 onRemove={localRemoveTag}
             />
-        </Segment>
+        </Panel>
 
-        <Tab menu={tabMenu} panes={tabPanes}/>
+        <Tabs defaultValue='about'>
+            <Tabs.List>
+                <Tabs.Tab value='about'>About</Tabs.Tab>
+                <Tabs.Tab value='files'>Files</Tabs.Tab>
+            </Tabs.List>
+            <Tabs.Panel value='about' pt='md'>
+                <Header as={'h3'}>Domain</Header>
+                {domainHeader}
 
-        <Segment>
+                <Header as='h3'>Size</Header>
+                {humanFileSize(size)}
+
+                <Header as={'h3'}>URL</Header>
+                <p>{archiveFile.url ? <a href={archiveFile.url}>{archiveFile.url}</a> : 'N/A'}</p>
+
+                <Header as={'h3'}>Modified Date</Header>
+                <p>{modifiedDatetimeString}</p>
+            </Tabs.Panel>
+            <Tabs.Panel value='files' pt='md'>
+                <table style={tableStyle}>
+                    <tbody>
+                    <tr>
+                        <td style={labelStyle}><strong>Singlefile File</strong></td>
+                        <td>{localPreviewPath(data.singlefile_path, 'text/html')}</td>
+                    </tr>
+                    <tr>
+                        <td style={labelStyle}><strong>Readability File</strong></td>
+                        <td>{localPreviewPath(data.readability_path, 'text/html')}</td>
+                    </tr>
+                    <tr>
+                        <td style={labelStyle}><strong>Readability Text File</strong></td>
+                        <td>{localPreviewPath(data.readability_txt_path, 'text/plain')}</td>
+                    </tr>
+                    <tr>
+                        <td style={labelStyle}><strong>Readability JSON File</strong></td>
+                        <td>{localPreviewPath(data.readability_json_path, 'application/json')}</td>
+                    </tr>
+                    <tr>
+                        <td style={labelStyle}><strong>Screenshot File</strong></td>
+                        <td>
+                            {screenshotPath
+                                ? <><PreviewPath path={screenshotPath} mimetype='image/*'
+                                                 taggable={false}>{screenshotPath}</PreviewPath>{findFileSize(screenshotPath)}</>
+                                : 'Unknown'}
+                        </td>
+                    </tr>
+                    <tr>
+                        <td style={labelStyle}><strong>Directory</strong></td>
+                        <td><DirectoryLink path={archiveFile.directory}/></td>
+                    </tr>
+                    </tbody>
+                </table>
+            </Tabs.Panel>
+        </Tabs>
+
+        <Panel>
             <InfoHeader
                 headerContent='History'
                 popupContent='Other archives of this URL created at different times.'
             />
             {historyList}
-        </Segment>
+        </Panel>
 
         <TaggedDeleteConfirmModal
             open={taggedFileGroups !== null}
@@ -377,7 +367,6 @@ function ArchivePage() {
 }
 
 export function ArchiveCard({file}) {
-    const {s} = useContext(ThemeContext);
     const {sort} = useSearchOrder();
     const sortField = sort ? sort.replace(/^-/, '') : null;
     const {data, directory} = file;
@@ -389,56 +378,69 @@ export function ArchiveCard({file}) {
     const imageSrc = screenshotPath ? `/media/${encodeMediaPath(screenshotPath)}` : null;
     const singlefileUrl = singlefilePath ? `/media/${encodeMediaPath(singlefilePath)}` : null;
 
-    let screenshot = <Card.Icon><FileIcon file={file}/></Card.Icon>;
-    const imageLabel = file.tags && file.tags.length ? taggedImageLabel : null;
+    // Marks a tagged file, pinned to the poster's corner (same convention as CardPoster).
+    const cardTagIcon = <div className='wrolpi-card-tag'><Icon name='tag' size={14} label='Tagged'/></div>;
+    const imageLabel = !_.isEmpty(file.tags) ? cardTagIcon : null;
+
+    let media;
     if (imageSrc) {
-        screenshot = <Image src={imageSrc} wrapped style={{position: 'relative', width: '100%'}} label={imageLabel}/>;
+        media = <ExternalCardLink to={singlefileUrl}>
+            <div style={{position: 'relative'}}>
+                {imageLabel}
+                <img alt='' src={imageSrc} style={{width: '100%', display: 'block'}}/>
+            </div>
+        </ExternalCardLink>;
+    } else {
+        media = <ExternalCardLink to={singlefileUrl}>
+            <div className='wrolpi-card-icon'>
+                {imageLabel}
+                <FileIcon file={file}/>
+            </div>
+        </ExternalCardLink>;
     }
 
     const domain = data ? data.domain : null;
     const domainUrl = `/archives?domain=${domain}`;
 
     const title = file.title || data.url;
-    const header = <ExternalCardLink to={singlefileUrl} className='card-title-ellipsis'>{title}</ExternalCardLink>;
+    const titleElm = <Tooltip label={title}>
+        <ExternalCardLink to={singlefileUrl} className='card-title-ellipsis'>{title}</ExternalCardLink>
+    </Tooltip>;
     const dt = file.published_datetime || file.published_modified_datetime || file.modified;
-    return <Card color={mimetypeColor(file.mimetype)}>
+
+    const meta = <>
+        {domain && <div>
+            <CardLink to={domainUrl}>{domain}</CardLink>
+        </div>}
         <div>
-            <ExternalCardLink to={singlefileUrl}>
-                {screenshot}
-            </ExternalCardLink>
+            {sortField === 'published_modified_datetime'
+                ? isoDatetimeToAgoPopup(file.published_modified_datetime, false)
+                : sortField === 'download_datetime'
+                ? isoDatetimeToAgoPopup(file.download_datetime, false)
+                : sortField === 'size'
+                ? humanFileSize(file.size)
+                : sortField === 'viewed'
+                ? isoDatetimeToAgoPopup(file.viewed, false)
+                : isoDatetimeToAgoPopup(dt, false)
+            }
+        </div>
+    </>;
+
+    return <Card media={media} title={titleElm} meta={meta}
+                 color={mimetypeColor(file.mimetype, file.primary_path)}>
+        <div style={{display: 'flex', gap: '0.5em', marginTop: '0.5em'}}>
+            <Link to={`/archives/${file.id}`}>
+                <Button icon='file alternate'>Details</Button>
+            </Link>
+            <IconButton
+                icon='external'
+                label='Open original URL'
+                component='a'
+                href={file.url}
+                target='_blank'
+                rel='noopener noreferrer'
+            />
         </div>
-        <CardContent {...s}>
-            <CardHeader>
-                <Container textAlign='left'>
-                    <Popup on='hover'
-                           trigger={header}
-                           content={title}/>
-                </Container>
-            </CardHeader>
-            {domain &&
-                <CardLink to={domainUrl}>
-                    <span {...s}>{domain}</span>
-                </CardLink>}
-            <CardMeta {...s}>
-                {sortField === 'published_modified_datetime'
-                    ? isoDatetimeToAgoPopup(file.published_modified_datetime, false)
-                    : sortField === 'download_datetime'
-                    ? isoDatetimeToAgoPopup(file.download_datetime, false)
-                    : sortField === 'size'
-                    ? humanFileSize(file.size)
-                    : sortField === 'viewed'
-                    ? isoDatetimeToAgoPopup(file.viewed, false)
-                    : isoDatetimeToAgoPopup(dt, false)
-                }
-            </CardMeta>
-            <CardDescription>
-                <Link to={`/archives/${file.id}`}>
-                    <Button icon='file alternate' content='Details'
-                            labelPosition='left'/>
-                </Link>
-                <Button icon='external' href={file.url} target='_blank' rel='noopener noreferrer'/>
-            </CardDescription>
-        </CardContent>
     </Card>
 }
 
@@ -471,25 +473,15 @@ function DomainStatistics({statistics}) {
         return <></>
     }
 
-    return <Segment>
+    return <Panel>
         <Header as='h1'>Statistics</Header>
-        <Statistic>
-            <StatisticValue>{statistics.archive_count}</StatisticValue>
-            <StatisticLabel>Archives</StatisticLabel>
-        </Statistic>
-        <Statistic>
-            <StatisticValue>{humanFileSize(statistics.size, true)}</StatisticValue>
-            <StatisticLabel>Total Size</StatisticLabel>
-        </Statistic>
-        <Statistic>
-            <StatisticValue>{humanFileSize(statistics.largest_archive, true)}</StatisticValue>
-            <StatisticLabel>Largest Archive</StatisticLabel>
-        </Statistic>
-        <Statistic>
-            <StatisticValue>{humanNumber(statistics.archive_tags)}</StatisticValue>
-            <StatisticLabel>Archive Tags</StatisticLabel>
-        </Statistic>
-    </Segment>
+        <StatisticGroup>
+            <Statistic value={statistics.archive_count} label='Archives'/>
+            <Statistic value={humanFileSize(statistics.size, true)} label='Total Size'/>
+            <Statistic value={humanFileSize(statistics.largest_archive, true)} label='Largest Archive'/>
+            <Statistic value={humanNumber(statistics.archive_tags)} label='Archive Tags'/>
+        </StatisticGroup>
+    </Panel>
 }
 
 export function DomainsPage() {
@@ -507,35 +499,29 @@ export function DomainsPage() {
     }, {enableOnFormTags: false});
 
     // Header section matching ChannelsPage pattern
-    const header = <div style={{marginBottom: '1em'}}>
-        <Grid stackable columns={2}>
-            <Grid.Row>
-                <Grid.Column>
-                    <SearchInput
-                        placeholder='Domain filter...'
-                        size='large'
-                        searchStr={searchStr}
-                        disabled={!Array.isArray(domains) || domains.length === 0}
-                        onClear={() => setSearchStr('')}
-                        onChange={setSearchStr}
-                        onSubmit={null}
-                        inputRef={searchInputRef}
-                    />
-                </Grid.Column>
-                <Grid.Column textAlign='right'>
-                    {/* No "New Domain" button - domains are auto-created */}
-                </Grid.Column>
-            </Grid.Row>
-        </Grid>
+    const header = <div style={{marginBottom: '1em', display: 'flex', flexWrap: 'wrap', gap: '1em', alignItems: 'center'}}>
+        <div style={{flex: '1 1 240px'}}>
+            <SearchInput
+                placeholder='Domain filter...'
+                size='large'
+                searchStr={searchStr}
+                disabled={!Array.isArray(domains) || domains.length === 0}
+                onClear={() => setSearchStr('')}
+                onChange={setSearchStr}
+                onSubmit={null}
+                inputRef={searchInputRef}
+            />
+        </div>
+        <div style={{flex: '1 1 240px', textAlign: 'right'}}>
+            {/* No "New Domain" button - domains are auto-created */}
+        </div>
     </div>;
 
     // Empty state
     if (domains && domains.length === 0) {
         return <>
             {header}
-            <Message>
-                <Message.Header>No domains yet. Archive some webpages!</Message.Header>
-            </Message>
+            <Message kind='info' title='No domains yet. Archive some webpages!'/>
         </>;
     }
 
@@ -633,13 +619,12 @@ export function DomainEditPage() {
         if (form.error) {
             return <>
                 <BackButton/>
-                <Message error>
-                    <Message.Header>Domain not found</Message.Header>
+                <Message kind='error' title='Domain not found'>
                     <p>{form.error}</p>
                 </Message>
             </>;
         }
-        return <Loader active>Loading domain...</Loader>;
+        return <Loading>Loading domain...</Loading>;
     }
 
     // Handler for domain deletion
@@ -655,10 +640,10 @@ export function DomainEditPage() {
     };
 
     const deleteButton = <APIButton
-        color='red'
+        role='danger'
         size='small'
         confirmContent='Are you sure you want to delete this domain? No archive files will be deleted, but archives will be orphaned.'
-        confirmButton='Delete'
+        confirmButton='Delete Domain'
         confirmHeader='Delete Domain?'
         onClick={handleDelete}
         obeyWROLMode={true}
@@ -709,8 +694,7 @@ export function DomainEditPage() {
         </Link>
 
         {domain?.needs_reorganization && (
-            <Message warning>
-                <Message.Header>File Format Changed</Message.Header>
+            <Message kind='warning' title='File Format Changed'>
                 <p>
                     The file name format has changed. Click "Reorganize Files" to move existing files
                     to match the new format.
@@ -725,29 +709,33 @@ export function DomainEditPage() {
             actionButtons={actionButtons}
             appliedTagName={domain?.tag_name}
         >
-            <GridRow>
-                <GridColumn>
+            {/*
+             * CollectionEditForm still wraps its children in a `ui stackable grid` div (Semantic's
+             * grid CSS, not a component) because it is shared with unmigrated callers (Channels.js,
+             * Playlists.js). Plain "row"/"column" divs are that CSS's own class names, not a
+             * semantic-ui-react import.
+             */}
+            <div className="row">
+                <div className="column">
                     <DestinationForm
                         form={form}
                         label='Directory'
                         name='directory'
                         path='directory'
                     />
-                </GridColumn>
-            </GridRow>
-            <GridRow>
-                <GridColumn>
-                    <Form.Field>
-                        <label>Description</label>
-                        <TextArea
-                            placeholder='Optional description'
-                            {...descriptionProps}
-                            onChange={(e, {value}) => descriptionProps.onChange(value)}
-                            rows={3}
-                        />
-                    </Form.Field>
-                </GridColumn>
-            </GridRow>
+                </div>
+            </div>
+            <div className="row">
+                <div className="column">
+                    <label style={{display: 'block', marginBottom: 4}}>Description</label>
+                    <Textarea
+                        placeholder='Optional description'
+                        value={descriptionProps.value || ''}
+                        onChange={(e) => descriptionProps.onChange(e.target.value)}
+                        rows={3}
+                    />
+                </div>
+            </div>
         </CollectionEditForm>
 
         {/* Tag Modal */}
@@ -772,14 +760,14 @@ export function DomainEditPage() {
             needsReorganization={domain?.needs_reorganization}
         />
 
-        {/* Downloads Segment */}
-        <Segment>
+        {/* Downloads Panel */}
+        <Panel>
             <Header as='h1'>Downloads</Header>
             <RecurringDownloadsTable
                 downloads={domain?.downloads}
                 fetchDownloads={fetchDomain}
             />
-        </Segment>
+        </Panel>
 
         {domain && domain.statistics && <DomainStatistics statistics={domain.statistics}/>}
     </>;
@@ -792,44 +780,45 @@ function ArchiveFileNameForm({form}) {
         const response = await postArchiveFileFormat(value);
         const {error, preview} = await response.json();
         if (error) {
-            setMessage({content: error, header: 'Invalid File Name', negative: true});
+            setMessage({kind: 'error', title: 'Invalid File Name', content: error});
         } else {
-            setMessage({content: preview, header: 'File Name Preview', positive: true});
+            setMessage({kind: 'success', title: 'File Name Preview', content: preview});
         }
     }
 
-    const label = <InfoHeader
-        headerSize='h5'
-        headerContent='Archive File Format'
-        popupProps={{wide: 'very', position: 'top left'}}
-        popupContent={<>
-            <p>Variables:</p>
-            <ul>
-                <li><code>%(title)s</code> - Page title</li>
-                <li><code>%(download_datetime)s</code> - Full datetime (YYYY-MM-DD-HH-MM-SS)</li>
-                <li><code>%(download_date)s</code> - Date only (YYYY-MM-DD)</li>
-                <li><code>%(download_year)s</code> - Year</li>
-                <li><code>%(download_month)s</code> - Month (zero-padded)</li>
-                <li><code>%(download_day)s</code> - Day (zero-padded)</li>
-                <li><code>%(domain)s</code> - Domain name</li>
-                <li><code>%(ext)s</code> - File extension (required, must be at end)</li>
-            </ul>
-            <p>Subdirectories supported: <code>%(download_year)s/%(title)s.%(ext)s</code></p>
-        </>}
-    />;
+    const [inputProps] = form.getInputProps({name: 'file_name_format', path: 'file_name_format', onChange});
 
-    return <InputForm
-        form={form}
-        name='file_name_format'
-        path='file_name_format'
-        label={label}
-        onChange={onChange}
-        message={message}
-    />
+    return <div>
+        <InfoHeader
+            headerSize='h5'
+            headerContent='Archive File Format'
+            popupContent={<>
+                <p>Variables:</p>
+                <ul>
+                    <li><code>%(title)s</code> - Page title</li>
+                    <li><code>%(download_datetime)s</code> - Full datetime (YYYY-MM-DD-HH-MM-SS)</li>
+                    <li><code>%(download_date)s</code> - Date only (YYYY-MM-DD)</li>
+                    <li><code>%(download_year)s</code> - Year</li>
+                    <li><code>%(download_month)s</code> - Month (zero-padded)</li>
+                    <li><code>%(download_day)s</code> - Day (zero-padded)</li>
+                    <li><code>%(domain)s</code> - Domain name</li>
+                    <li><code>%(ext)s</code> - File extension (required, must be at end)</li>
+                </ul>
+                <p>Subdirectories supported: <code>%(download_year)s/%(title)s.%(ext)s</code></p>
+            </>}
+        />
+        <TextInput
+            id='file_name_format_input'
+            name='file_name_format'
+            value={inputProps.value ?? ''}
+            onChange={inputProps.onChange}
+            data-path={inputProps['data-path']}
+        />
+        {message && <Message kind={message.kind} title={message.title}>{message.content}</Message>}
+    </div>
 }
 
 function BrowserConfigForm({form, browsers, browsersAvailable}) {
-    const {t} = React.useContext(ThemeContext);
     const [useCustomPath, setUseCustomPath] = useState(false);
 
     // Determine if custom path is being used based on current value
@@ -848,12 +837,12 @@ function BrowserConfigForm({form, browsers, browsersAvailable}) {
 
     // Build dropdown options: auto-detect + installed browsers + custom
     const browserOptions = [
-        {key: 'auto', value: '', text: 'Auto-detect (recommended)'},
-        ...browsers.map(b => ({key: b.key, value: b.path, text: `${b.name} (${b.path})`})),
-        {key: 'custom', value: '__custom__', text: 'Custom path...'},
+        {value: '', label: 'Auto-detect (recommended)'},
+        ...browsers.map(b => ({value: b.path, label: `${b.name} (${b.path})`})),
+        {value: '__custom__', label: 'Custom path...'},
     ];
 
-    const handleBrowserChange = (e, {value}) => {
+    const handleBrowserChange = (value) => {
         if (value === '__custom__') {
             setUseCustomPath(true);
             form.setValue('browser_executable', '');
@@ -868,63 +857,60 @@ function BrowserConfigForm({form, browsers, browsersAvailable}) {
 
     return <>
         <Header as='h4'>Browser Settings</Header>
-        <p {...t}>
+        <p>
             Configure which browser SingleFile uses to create archives.
             These settings only apply to native deployments (Raspberry Pi/Debian).
         </p>
 
-        <Form.Field>
-            <label {...t}>Browser</label>
-            <Form.Dropdown
-                selection
-                options={browserOptions}
+        <div style={{marginBottom: '1em'}}>
+            <label style={{display: 'block', marginBottom: 4}}>Browser</label>
+            <Select
+                data={browserOptions}
                 value={dropdownValue}
                 onChange={handleBrowserChange}
                 placeholder='Select browser...'
             />
-        </Form.Field>
+        </div>
 
         {useCustomPath && (
-            <Form.Field>
-                <label {...t}>Custom Browser Path</label>
-                <Input
-                    fluid
+            <div style={{marginBottom: '1em'}}>
+                <label style={{display: 'block', marginBottom: 4}}>Custom Browser Path</label>
+                <TextInput
                     placeholder='/usr/bin/chromium'
                     value={form.formData?.browser_executable || ''}
                     onChange={(e) => form.setValue('browser_executable', e.target.value)}
                 />
-                <small {...t}>Enter the absolute path to the browser executable.</small>
-            </Form.Field>
+                <small style={{color: 'var(--muted)'}}>Enter the absolute path to the browser executable.</small>
+            </div>
         )}
 
-        <Form.Field>
-            <label {...t}>Browser Arguments</label>
-            <Input
-                fluid
+        <div style={{marginBottom: '1em'}}>
+            <label style={{display: 'block', marginBottom: 4}}>Browser Arguments</label>
+            <TextInput
                 placeholder='["--no-sandbox"]'
                 value={form.formData?.browser_args || '["--no-sandbox"]'}
                 onChange={(e) => form.setValue('browser_args', e.target.value)}
             />
-            <small {...t}>JSON array of arguments passed to the browser. Default: ["--no-sandbox"]</small>
-        </Form.Field>
+            <small style={{color: 'var(--muted)'}}>JSON array of arguments passed to the browser. Default:
+                ["--no-sandbox"]</small>
+        </div>
 
-        <Form.Field>
-            <label {...t}>User Agent</label>
-            <Input
-                fluid
+        <div>
+            <label style={{display: 'block', marginBottom: 4}}>User Agent</label>
+            <TextInput
                 placeholder='Leave empty to use system default'
                 value={form.formData?.user_agent || ''}
                 onChange={(e) => form.setValue('user_agent', e.target.value || null)}
             />
-            <small {...t}>Custom user agent string. Leave empty to use the system default.</small>
-        </Form.Field>
+            <small style={{color: 'var(--muted)'}}>Custom user agent string. Leave empty to use the system
+                default.</small>
+        </div>
     </>;
 }
 
 function ArchiveSettingsPage() {
     useTitle('Archive Settings');
 
-    const {t} = React.useContext(ThemeContext);
     const dockerized = useDockerized();
     const [batchModalOpen, setBatchModalOpen] = useState(false);
     const [domainsNeedingReorg, setDomainsNeedingReorg] = useState(0);
@@ -1002,46 +988,38 @@ function ArchiveSettingsPage() {
     />;
 
     return <PageContainer>
-        <Segment>
+        <Panel>
             <Header as='h3'>Archive Downloader Config</Header>
 
-            <Form>
-                <Grid>
-                    <GridRow columns={1}>
-                        <GridColumn mobile={16} computer={8}>
-                            <ArchiveFileNameForm form={configForm}/>
-                        </GridColumn>
-                    </GridRow>
+            <div style={{opacity: configForm.loading ? 0.6 : 1, pointerEvents: configForm.loading ? 'none' : 'auto'}}>
+                <div style={{maxWidth: 500, marginBottom: '1em'}}>
+                    <ArchiveFileNameForm form={configForm}/>
+                </div>
 
-                    {/* Browser settings - only shown on native deployments */}
-                    {!dockerized && browsersAvailable && (
-                        <GridRow columns={1}>
-                            <GridColumn mobile={16} computer={8}>
-                                <BrowserConfigForm
-                                    form={configForm}
-                                    browsers={browsers}
-                                    browsersAvailable={browsersAvailable}
-                                />
-                            </GridColumn>
-                        </GridRow>
-                    )}
+                {/* Browser settings - only shown on native deployments */}
+                {!dockerized && browsersAvailable && (
+                    <div style={{maxWidth: 500, marginBottom: '1em'}}>
+                        <BrowserConfigForm
+                            form={configForm}
+                            browsers={browsers}
+                            browsersAvailable={browsersAvailable}
+                        />
+                    </div>
+                )}
 
-                    <GridRow columns={1}>
-                        <GridColumn textAlign='right'>
-                            <APIButton
-                                disabled={configForm.disabled || !configForm.ready}
-                                type='submit'
-                                style={{marginTop: '0.5em'}}
-                                onClick={configForm.onSubmit}
-                                id='archive_settings_save_button'
-                            >Save</APIButton>
-                        </GridColumn>
-                    </GridRow>
-                </Grid>
-            </Form>
-        </Segment>
+                <div style={{textAlign: 'right'}}>
+                    <APIButton
+                        disabled={configForm.disabled || !configForm.ready}
+                        type='submit'
+                        style={{marginTop: '0.5em'}}
+                        onClick={configForm.onSubmit}
+                        id='archive_settings_save_button'
+                    >Save</APIButton>
+                </div>
+            </div>
+        </Panel>
 
-        <Segment>
+        <Panel>
             <Header as='h4'>File Organization</Header>
             <p>
                 {fetchingReorgCount
@@ -1056,14 +1034,15 @@ function ArchiveSettingsPage() {
             </p>
             <Button
                 color='orange'
+                icon='folder open outline'
                 onClick={() => setBatchModalOpen(true)}
                 id='reorganize_all_domains_button'
                 disabled={fetchingReorgCount || domainsNeedingReorg === 0}
                 loading={fetchingReorgCount}
             >
-                <Icon name='folder open outline'/> Reorganize All Domains
+                Reorganize All Domains
             </Button>
-        </Segment>
+        </Panel>
 
         <BatchReorganizeModal
             open={batchModalOpen}
@@ -1075,10 +1054,10 @@ function ArchiveSettingsPage() {
             }}
         />
 
-        <Segment>
+        <Panel>
             <Header as='h3'>SingleFile Browser Extension</Header>
 
-            <p {...t}>
+            <p>
                 These are the settings necessary to configure the <a
                 href="https://github.com/gildas-lormeau/SingleFile?tab=readme-ov-file#install"
                 rel='noopener noreferrer'
@@ -1086,22 +1065,22 @@ function ArchiveSettingsPage() {
                 Extension</a> to automatically upload to your WROLPi.
             </p>
 
-            <label {...t}>Upload URL</label>
-            <Input fluid
+            <label style={{display: 'block', marginBottom: 4}}>Upload URL</label>
+            <ActionInput readOnly
                    value={API_ARCHIVE_UPLOAD_URI}
-                   label={urlClipboardButton}
+                   action={urlClipboardButton}
             />
-            <label {...t}>Data Field Name</label>
-            <Input fluid
+            <label style={{display: 'block', marginBottom: 4, marginTop: '1em'}}>Data Field Name</label>
+            <ActionInput readOnly
                    value='singlefile_contents'
-                   label={dataFieldNameClipboardButton}
+                   action={dataFieldNameClipboardButton}
             />
-            <label {...t}>URL Field Name</label>
-            <Input fluid
+            <label style={{display: 'block', marginBottom: 4, marginTop: '1em'}}>URL Field Name</label>
+            <ActionInput readOnly
                    value='url'
-                   label={urlFieldNameClipboardButton}
+                   action={urlFieldNameClipboardButton}
             />
-        </Segment>
+        </Panel>
     </PageContainer>
 }
 
@@ -1191,26 +1170,26 @@ function ArchivesPage() {
 
     const selectElm = <div style={{marginTop: '0.5em'}}>
         <Button
-            color='violet'
+            role='primary'
             disabled={_.isEmpty(selectedArchives)}
             onClick={() => setBulkTagOpen(true)}
         >Tag</Button>
         <APIButton
-            color='red'
+            role='danger'
             disabled={_.isEmpty(selectedArchives)}
             confirmButton='Delete'
             confirmContent='Are you sure you want to delete these archives files?  This cannot be undone.'
             onClick={() => onDelete(false)}
         >Delete</APIButton>
         <Button
-            color='grey'
+            role='cancel'
             onClick={invertSelection}
             disabled={_.isEmpty(archives)}
         >
             Invert
         </Button>
         <Button
-            color='yellow'
+            role='cancel'
             onClick={clearSelection}
             disabled={_.isEmpty(archives) || _.isEmpty(selectedArchives)}
         >
@@ -1252,11 +1231,9 @@ function ArchivesPage() {
         </>;
     } else if (domain) {
         // Domain filter is set but domain object not loaded yet
-        header = <Placeholder style={{marginBottom: '1em'}}>
-            <PlaceholderHeader>
-                <PlaceholderLine/>
-            </PlaceholderHeader>
-        </Placeholder>;
+        header = <div style={{marginBottom: '1em'}}>
+            <Placeholder lines={1}/>
+        </div>;
     }
 
     return <>
@@ -1297,7 +1274,7 @@ export function ArchiveRowCells({file}) {
     let poster;
     if (posterUrl) {
         poster = <CardLink to={archiveUrl}>
-            <Image wrapped src={posterUrl} width='50px'/>
+            <img alt='' src={posterUrl} style={{width: '50px', height: 'auto'}}/>
         </CardLink>;
     } else {
         poster = <FileIcon file={file} size='large'/>;
@@ -1316,16 +1293,18 @@ export function ArchiveRowCells({file}) {
 
     // Fragment for SelectableRow
     return <React.Fragment>
-        <TableCell>
-            <center>{poster}</center>
-        </TableCell>
-        <TableCell>
+        <Table.Cell>
+            <div style={{textAlign: 'center'}}>
+                {poster}
+            </div>
+        </Table.Cell>
+        <Table.Cell>
             <CardLink to={archiveUrl}>
                 <FileRowTagIcon file={file}/>
                 {textEllipsis(file.title || file.stem)}
             </CardLink>
-        </TableCell>
-        <TableCell>{dataCell}</TableCell>
+        </Table.Cell>
+        <Table.Cell>{dataCell}</Table.Cell>
     </React.Fragment>
 }
 
@@ -1336,7 +1315,7 @@ function ArchiveStatistics() {
 
     if (statistics === null) {
         // Request is pending.
-        return <Loader active inline='centered'/>
+        return <Loading/>
     } else if (statistics === undefined) {
         return <ErrorMessage>Unable to fetch Archive Statistics</ErrorMessage>
     }
@@ -1360,25 +1339,22 @@ function ArchiveStatistics() {
         {key: 'tagged_domains', label: 'Tagged Domains'},
     ];
 
-    const buildSegment = (title, names, stats) => {
-        return <Segment>
-            <Header textAlign='center' as='h1'>{title}</Header>
-            <Statistic.Group>
+    const buildPanel = (title, names, stats) => {
+        return <Panel>
+            <Header as='h1' style={{textAlign: 'center'}}>{title}</Header>
+            <StatisticGroup>
                 {names.map(
                     ({key, label}) =>
-                        <Statistic key={key} style={{margin: '2em'}}>
-                            <StatisticValue>{stats[key]}</StatisticValue>
-                            <StatisticLabel>{label}</StatisticLabel>
-                        </Statistic>
+                        <Statistic key={key} value={stats[key]} label={label}/>
                 )}
-            </Statistic.Group>
-        </Segment>
+            </StatisticGroup>
+        </Panel>
     }
 
     return <>
-        {buildSegment('Archives', archiveNames, archives)}
-        {buildSegment('Historical Archives', historicalNames, historical)}
-        {buildSegment('Domains', domainNames, domains)}
+        {buildPanel('Archives', archiveNames, archives)}
+        {buildPanel('Historical Archives', historicalNames, historical)}
+        {buildPanel('Domains', domainNames, domains)}
     </>
 }
 
diff --git a/app/src/components/BulkTagModal.js b/app/src/components/BulkTagModal.js
index 8e12f51a..b3228569 100644
--- a/app/src/components/BulkTagModal.js
+++ b/app/src/components/BulkTagModal.js
@@ -1,9 +1,7 @@
 import React from 'react';
-import {Button, Divider, Header, Loader, Modal, Progress} from "./Theme";
-import Message from "semantic-ui-react/dist/commonjs/collections/Message";
+import {Button, Divider, Header, Loading, Message, Modal, Progress} from "./ui";
 import {applyBulkTags, getBulkTagPreview, getBulkTagProgress} from "../api";
 import {TagsContext} from "../Tags";
-import {ThemeContext} from "../contexts/contexts";
 
 const BULK_TAG_WARNING_THRESHOLD = 50;
 const POLL_INTERVAL = 500; // Poll progress every 500ms
@@ -18,7 +16,6 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
     const [error, setError] = React.useState(null);
 
     const {tagNames, TagsGroup} = React.useContext(TagsContext);
-    const {t} = React.useContext(ThemeContext);
 
     // Fetch preview when modal opens
     React.useEffect(() => {
@@ -132,16 +129,13 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
             <Modal.Header>Bulk Tag Files</Modal.Header>
             <Modal.Content>
                 {state === 'loading' && (
-                    <div style={{textAlign: 'center', padding: '2em'}}>
-                        <Loader active inline="centered">Loading preview...</Loader>
-                    </div>
+                    <Loading>Loading preview...</Loading>
                 )}
 
                 {state === 'preview' && (
                     <>
                         {error && (
-                            <Message negative>
-                                <Message.Header>Error</Message.Header>
+                            <Message kind='error' title='Error'>
                                 <p>{error}</p>
                             </Message>
                         )}
@@ -151,8 +145,7 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
                         </Header>
 
                         {showWarning && (
-                            <Message warning>
-                                <Message.Header>Warning</Message.Header>
+                            <Message kind='warning' title='Warning'>
                                 <p>Tagging over {BULK_TAG_WARNING_THRESHOLD} files may make it difficult to find what you are looking for. Are you sure?</p>
                             </Message>
                         )}
@@ -163,7 +156,7 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
                         {localTags.length > 0 ? (
                             <TagsGroup tagNames={localTags} onClick={removeTag}/>
                         ) : (
-                            <p {...t}>Add one or more tags below</p>
+                            <p>Add one or more tags below</p>
                         )}
 
                         <Divider/>
@@ -171,7 +164,7 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
                         {unusedTags.length > 0 ? (
                             <TagsGroup tagNames={unusedTags} onClick={addTag}/>
                         ) : (
-                            <p {...t}>You have no tags</p>
+                            <p>You have no tags</p>
                         )}
                     </>
                 )}
@@ -181,18 +174,14 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
                         <Header as="h4">Applying tags...</Header>
                         <Progress
                             percent={progressPercent}
-                            progress
-                            indicating
                             color="blue"
-                        >
-                            <span {...t}>{progress.completed} / {progress.total} files</span>
-                        </Progress>
+                            label={`${progress.completed} / ${progress.total} files`}
+                        />
                         {progress.queued_jobs > 0 && (
-                            <p {...t}>{progress.queued_jobs} job{progress.queued_jobs !== 1 ? 's' : ''} queued</p>
+                            <p>{progress.queued_jobs} job{progress.queued_jobs !== 1 ? 's' : ''} queued</p>
                         )}
                         {error && (
-                            <Message negative>
-                                <Message.Header>Error</Message.Header>
+                            <Message kind='error' title='Error'>
                                 <p>{error}</p>
                             </Message>
                         )}
@@ -201,13 +190,11 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
 
                 {state === 'complete' && (
                     <div style={{padding: '1em'}}>
-                        <Message positive>
-                            <Message.Header>Complete</Message.Header>
+                        <Message kind='success' title='Complete'>
                             <p>Successfully tagged {progress.total} file{progress.total !== 1 ? 's' : ''}.</p>
                         </Message>
                         {error && (
-                            <Message warning>
-                                <Message.Header>Warning</Message.Header>
+                            <Message kind='warning' title='Warning'>
                                 <p>Some errors occurred: {error}</p>
                             </Message>
                         )}
@@ -217,7 +204,7 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
             <Modal.Actions>
                 {state === 'preview' && (
                     <>
-                        <Button onClick={handleClose}>Cancel</Button>
+                        <Button role='cancel' onClick={handleClose}>Cancel</Button>
                         <Button
                             color="violet"
                             onClick={handleApply}
@@ -228,12 +215,12 @@ export function BulkTagModal({open, onClose, paths, onComplete}) {
                     </>
                 )}
                 {state === 'applying' && (
-                    <Button onClick={handleClose} disabled>
+                    <Button role='cancel' onClick={handleClose} disabled>
                         Please wait...
                     </Button>
                 )}
                 {state === 'complete' && (
-                    <Button color="green" onClick={handleClose}>
+                    <Button role='save' onClick={handleClose}>
                         Done
                     </Button>
                 )}
diff --git a/app/src/components/BulkTagModal.test.js b/app/src/components/BulkTagModal.test.js
index 55309499..ee2ee5b8 100644
--- a/app/src/components/BulkTagModal.test.js
+++ b/app/src/components/BulkTagModal.test.js
@@ -1,7 +1,8 @@
 import React from 'react';
-import {act, render, screen, waitFor} from '@testing-library/react';
+import {act, screen, waitFor} from '@testing-library/react';
 import {BulkTagModal} from './BulkTagModal';
 import {TagsContext} from '../Tags';
+import {renderWithProviders} from '../test-utils';
 
 // Mock the API functions
 jest.mock('../api', () => ({
@@ -10,42 +11,6 @@ jest.mock('../api', () => ({
     getBulkTagProgress: jest.fn(),
 }));
 
-// Mock Theme components with compound patterns
-jest.mock('./Theme', () => {
-    const MockModal = ({open, onClose, children, closeIcon}) => {
-        if (!open) return null;
-        return (
-            <div data-testid="modal">
-                {closeIcon && <button data-testid="close-icon" onClick={onClose}>x</button>}
-                {children}
-            </div>
-        );
-    };
-    MockModal.Header = ({children}) => <div data-testid="modal-header">{children}</div>;
-    MockModal.Content = ({children}) => <div data-testid="modal-content">{children}</div>;
-    MockModal.Actions = ({children}) => <div data-testid="modal-actions">{children}</div>;
-    MockModal.Description = ({children}) => <div data-testid="modal-description">{children}</div>;
-
-    return {
-        ...jest.requireActual('./Theme'),
-        Modal: MockModal,
-        Button: ({children, onClick, disabled, color, ...props}) => (
-            <button onClick={onClick} disabled={disabled} data-testid={`button-${children}`} {...props}>{children}</button>
-        ),
-        Header: ({children, as}) => <div data-testid="header">{children}</div>,
-        Divider: () => <hr data-testid="divider"/>,
-        Loader: ({children}) => <div data-testid="loader">{children}</div>,
-        Message: ({children, warning, negative, positive}) => (
-            <div data-testid={`message-${warning ? 'warning' : negative ? 'negative' : positive ? 'positive' : 'info'}`}>
-                {children}
-            </div>
-        ),
-        Progress: ({percent, children}) => (
-            <div data-testid="progress" data-percent={percent}>{children}</div>
-        ),
-    };
-});
-
 // Import mocked API functions
 import {getBulkTagPreview, applyBulkTags, getBulkTagProgress} from '../api';
 
@@ -60,23 +25,18 @@ const MockTagsGroup = ({tagNames, onClick}) => (
     </div>
 );
 
-// Create a wrapper with TagsContext
-const TagsContextWrapper = ({children}) => {
+// Render with the real ui library components (Mantine-backed) plus TagsContext.
+const renderWithTags = (ui, options) => {
     const tagsValue = {
         tagNames: ['tag1', 'tag2', 'tag3'],
         TagsGroup: MockTagsGroup,
     };
-    return (
-        <TagsContext.Provider value={tagsValue}>
-            {children}
-        </TagsContext.Provider>
+    return renderWithProviders(
+        <TagsContext.Provider value={tagsValue}>{ui}</TagsContext.Provider>,
+        options,
     );
 };
 
-// Custom render function with TagsContext
-const renderWithTags = (ui, options) =>
-    render(ui, {wrapper: TagsContextWrapper, ...options});
-
 describe('BulkTagModal', () => {
     const defaultProps = {
         open: true,
@@ -102,17 +62,17 @@ describe('BulkTagModal', () => {
     describe('Modal Rendering', () => {
         it('renders modal when open is true', async () => {
             renderWithTags(<BulkTagModal {...defaultProps} />);
-            expect(screen.getByTestId('modal')).toBeInTheDocument();
+            expect(screen.getByRole('dialog')).toBeInTheDocument();
         });
 
         it('does not render modal when open is false', () => {
             renderWithTags(<BulkTagModal {...defaultProps} open={false}/>);
-            expect(screen.queryByTestId('modal')).not.toBeInTheDocument();
+            expect(screen.queryByRole('dialog')).not.toBeInTheDocument();
         });
 
         it('shows header', async () => {
             renderWithTags(<BulkTagModal {...defaultProps} />);
-            expect(screen.getByTestId('modal-header')).toHaveTextContent('Bulk Tag Files');
+            expect(screen.getByText('Bulk Tag Files')).toBeInTheDocument();
         });
     });
 
@@ -121,7 +81,7 @@ describe('BulkTagModal', () => {
             getBulkTagPreview.mockImplementation(() => new Promise(() => {
             })); // Never resolves
             renderWithTags(<BulkTagModal {...defaultProps} />);
-            expect(screen.getByTestId('loader')).toBeInTheDocument();
+            expect(screen.getByText('Loading preview...')).toBeInTheDocument();
         });
     });
 
@@ -142,7 +102,7 @@ describe('BulkTagModal', () => {
             await waitFor(() => {
                 expect(screen.getByText(/10 files will be affected/i)).toBeInTheDocument();
             });
-            expect(screen.queryByTestId('message-warning')).not.toBeInTheDocument();
+            expect(screen.queryByText(/Tagging over 50 files/i)).not.toBeInTheDocument();
         });
 
         it('Apply button is disabled when no changes', async () => {
@@ -150,7 +110,7 @@ describe('BulkTagModal', () => {
             await waitFor(() => {
                 expect(screen.getByText(/2 files will be affected/i)).toBeInTheDocument();
             });
-            const applyButton = screen.getByTestId('button-Apply Tags');
+            const applyButton = screen.getByRole('button', {name: 'Apply Tags'});
             expect(applyButton).toBeDisabled();
         });
     });
@@ -183,7 +143,7 @@ describe('BulkTagModal', () => {
             await waitFor(() => {
                 expect(screen.getByText(/2 files will be affected/i)).toBeInTheDocument();
             });
-            const cancelButton = screen.getByTestId('button-Cancel');
+            const cancelButton = screen.getByRole('button', {name: 'Cancel'});
             act(() => {
                 cancelButton.click();
             });
@@ -197,7 +157,7 @@ describe('BulkTagModal', () => {
             getBulkTagPreview.mockResolvedValue(undefined);
             renderWithTags(<BulkTagModal {...defaultProps} />);
             // Modal should still be visible
-            expect(screen.getByTestId('modal')).toBeInTheDocument();
+            expect(screen.getByRole('dialog')).toBeInTheDocument();
         });
     });
 });
diff --git a/app/src/components/Channels.js b/app/src/components/Channels.js
index c6669b3e..44feaecf 100644
--- a/app/src/components/Channels.js
+++ b/app/src/components/Channels.js
@@ -1,6 +1,5 @@
 import React, {useState} from "react";
 import {useHotkeys} from "react-hotkeys-hook";
-import {Grid, StatisticLabel, StatisticValue,} from "semantic-ui-react";
 import {createChannel, deleteChannel, refreshChannel, tagChannel, tagChannelInfo} from "../api";
 import {CollectionTagModal} from "./collections/CollectionTagModal";
 import {CollectionReorganizeModal} from "./collections/CollectionReorganizeModal";
@@ -18,11 +17,22 @@ import {
     WROLModeMessage
 } from "./Common";
 import {Link, useNavigate, useParams} from "react-router";
-import Message from "semantic-ui-react/dist/commonjs/collections/Message";
 import {useChannel, useChannels, useOneQuery} from "../hooks/customHooks";
 import _ from "lodash";
-import {Button, Form, Header, Loader, Modal, Segment, Statistic} from "./Theme";
-import {toast} from "./ui";
+import {
+    Button,
+    Grid,
+    Group,
+    Header,
+    Loading,
+    Message,
+    Modal,
+    Panel,
+    Stack,
+    Statistic,
+    StatisticGroup,
+    toast,
+} from "./ui";
 import {RecurringDownloadsTable} from "./admin/Downloads";
 import {InputForm, ToggleForm} from "../hooks/useForm";
 import {ChannelDownloadForm, DestinationForm, DownloadTagsSelector} from "./Download";
@@ -58,29 +68,16 @@ function ChannelStatistics({statistics}) {
         return <></>
     }
 
-    return <Segment>
+    return <Panel>
         <Header as='h1'>Statistics</Header>
-        <Statistic>
-            <StatisticValue>{statistics.video_count}</StatisticValue>
-            <StatisticLabel>Videos</StatisticLabel>
-        </Statistic>
-        <Statistic>
-            <StatisticValue>{humanFileSize(statistics.size, true)}</StatisticValue>
-            <StatisticLabel>Total Size</StatisticLabel>
-        </Statistic>
-        <Statistic>
-            <StatisticValue>{humanFileSize(statistics.largest_video, true)}</StatisticValue>
-            <StatisticLabel>Largest Video</StatisticLabel>
-        </Statistic>
-        <Statistic>
-            <StatisticValue>{secondsToFullDuration(statistics.length)}</StatisticValue>
-            <StatisticLabel>Total Duration</StatisticLabel>
-        </Statistic>
-        <Statistic>
-            <StatisticValue>{humanNumber(statistics.video_tags)}</StatisticValue>
-            <StatisticLabel>Video Tags</StatisticLabel>
-        </Statistic>
-    </Segment>
+        <StatisticGroup>
+            <Statistic value={statistics.video_count} label='Videos'/>
+            <Statistic value={humanFileSize(statistics.size, true)} label='Total Size'/>
+            <Statistic value={humanFileSize(statistics.largest_video, true)} label='Largest Video'/>
+            <Statistic value={secondsToFullDuration(statistics.length)} label='Total Duration'/>
+            <Statistic value={humanNumber(statistics.video_tags)} label='Video Tags'/>
+        </StatisticGroup>
+    </Panel>
 }
 
 
@@ -97,7 +94,7 @@ export function ChannelEditPage() {
     useTitle(_.isEmpty(channel) ? null : `${channel.name} Channel`);
 
     if (!form.ready) {
-        return <Loader active/>;
+        return <Loading/>;
     }
 
     const handleRefreshChannel = async (e) => {
@@ -169,7 +166,7 @@ export function ChannelEditPage() {
     };
 
     const deleteButton = <APIButton
-        color='red'
+        role='danger'
         size='small'
         confirmContent='Are you sure you want to delete this channel? No video files will be deleted.'
         confirmButton='Delete'
@@ -180,7 +177,7 @@ export function ChannelEditPage() {
     >Delete</APIButton>;
 
     const refreshButton = <APIButton
-        color='blue'
+        role='primary'
         size='small'
         onClick={handleRefreshChannel}
         obeyWROLMode={true}
@@ -191,13 +188,13 @@ export function ChannelEditPage() {
         type="button"
         size='small'
         onClick={() => setTagEditModalOpen(true)}
-        color='violet'
+        role='primary'
         style={{marginTop: '1em'}}
     >Tag</Button>;
 
     const reorganizeButton = (
         <APIButton
-            color='orange'
+            role='retry'
             size='small'
             onClick={() => setReorganizeModalOpen(true)}
             obeyWROLMode={true}
@@ -222,8 +219,7 @@ export function ChannelEditPage() {
         </Link>
 
         {channel?.needs_reorganization && (
-            <Message warning>
-                <Message.Header>File Format Changed</Message.Header>
+            <Message kind='warning' title='File Format Changed'>
                 <p>
                     The file name format has changed. Click "Reorganize Files" to move existing files
                     to match the new format.
@@ -239,8 +235,8 @@ export function ChannelEditPage() {
             appliedTagName={channel?.tag_name}
             onSubmit={handleSubmit}
         >
-            <Grid.Row>
-                <Grid.Column width={8}>
+            <Grid>
+                <Grid.Col span={{base: 12, sm: 6}}>
                     <InputForm
                         form={form}
                         label="Channel Name"
@@ -248,8 +244,8 @@ export function ChannelEditPage() {
                         placeholder="Short Channel Name"
                         required={true}
                     />
-                </Grid.Column>
-                <Grid.Column width={8}>
+                </Grid.Col>
+                <Grid.Col span={{base: 12, sm: 6}}>
                     <DestinationForm
                         form={form}
                         label='Directory'
@@ -257,38 +253,30 @@ export function ChannelEditPage() {
                         path='directory'
                         required={true}
                     />
-                </Grid.Column>
-            </Grid.Row>
-            <Grid.Row>
-                <Grid.Column>
+                </Grid.Col>
+                <Grid.Col span={12}>
                     <ToggleForm
                         form={form}
                         label={downloadMissingDataLabel}
                         path='download_missing_data'
                     />
-                </Grid.Column>
-            </Grid.Row>
-            {(channel.url || channel.rss_url) &&
-                <Grid.Row>
-                    <Grid.Column>
+                </Grid.Col>
+                {(channel.url || channel.rss_url) &&
+                    <Grid.Col span={12}>
                         <SimpleAccordion title='Details'>
-                            <Grid>
-                                {channel.url && <Grid.Row columns={1}>
-                                    <Grid.Column>
-                                        <Header as='h4'>URL</Header>
-                                        <a href={channel.url}>{channel.url}</a>
-                                    </Grid.Column>
-                                </Grid.Row>}
-                                {channel.rss_url && <Grid.Row columns={1}>
-                                    <Grid.Column>
-                                        <Header as='h4'>RSS URL</Header>
-                                        <a href={channel.rss_url}>{channel.rss_url}</a>
-                                    </Grid.Column>
-                                </Grid.Row>}
-                            </Grid>
+                            <Stack gap='sm'>
+                                {channel.url && <div>
+                                    <Header as='h4'>URL</Header>
+                                    <a href={channel.url}>{channel.url}</a>
+                                </div>}
+                                {channel.rss_url && <div>
+                                    <Header as='h4'>RSS URL</Header>
+                                    <a href={channel.rss_url}>{channel.rss_url}</a>
+                                </div>}
+                            </Stack>
                         </SimpleAccordion>
-                    </Grid.Column>
-                </Grid.Row>}
+                    </Grid.Col>}
+            </Grid>
         </CollectionEditForm>
 
         {/* Tag Modal */}
@@ -314,22 +302,14 @@ export function ChannelEditPage() {
         />
 
         {/* Downloads Segment */}
-        <Segment>
-            <Grid columns={2}>
-                <Grid.Row>
-                    <Grid.Column>
-                        <Header as='h1'>Downloads</Header>
-                    </Grid.Column>
-                    <Grid.Column>
-                        <Button floated='right'
-                                onClick={() => setDownloadModalOpen(!downloadModalOpen)}
-                        >
-                            New Download
-                        </Button>
-                    </Grid.Column>
-                </Grid.Row>
-            </Grid>
-            <Modal open={downloadModalOpen} closeIcon onClose={() => setDownloadModalOpen(false)}>
+        <Panel>
+            <Group justify='space-between' align='center' wrap='wrap'>
+                <Header as='h1'>Downloads</Header>
+                <Button onClick={() => setDownloadModalOpen(!downloadModalOpen)}>
+                    New Download
+                </Button>
+            </Group>
+            <Modal open={downloadModalOpen} onClose={() => setDownloadModalOpen(false)}>
                 <Modal.Content>
                     <Header as='h2'>New Channel Download</Header>
                     <ChannelDownloadForm
@@ -342,7 +322,7 @@ export function ChannelEditPage() {
             </Modal>
 
             <RecurringDownloadsTable downloads={channel?.downloads} fetchDownloads={fetchChannel} onDelete={onDelete}/>
-        </Segment>
+        </Panel>
 
         {channel && channel.statistics && <ChannelStatistics statistics={channel.statistics}/>}
     </>;
@@ -434,88 +414,74 @@ export function ChannelNewPage() {
 
     let messageRow;
     if (error || success) {
-        messageRow = <Grid.Row columns={1}>
-            <Grid.Column>
-                {error &&
-                    <Message negative
-                             header={messageHeader}
-                             content={messageContent}
-                    />}
-                {success &&
-                    <Message positive
-                             header={messageHeader}
-                             content={messageContent}
-                    />}
-            </Grid.Column>
-        </Grid.Row>
+        messageRow = <Grid.Col span={12}>
+            {error &&
+                <Message kind='error' title={messageHeader}>{messageContent}</Message>}
+            {success &&
+                <Message kind='success' title={messageHeader}>{messageContent}</Message>}
+        </Grid.Col>
     }
 
     return <>
         <BackButton/>
 
-        <Segment>
+        <Panel>
             <Header as="h1">New Channel</Header>
             <WROLModeMessage content='Channel creation is disabled while WROL Mode is enabled.'/>
-            <Form
+            <form
                 id="newChannel"
-                error={error}
-                success={success}
                 autoComplete="off"
+                onSubmit={e => e.preventDefault()}
             >
-                <Grid stackable columns={2}>
-                    <Grid.Row>
-                        <Grid.Column>
-                            <InputForm
-                                form={form}
-                                label="Channel Name"
-                                name="name"
-                                placeholder="Short Channel Name"
-                                required={true}
-                            />
-                        </Grid.Column>
-                        <Grid.Column>
-                            <DestinationForm
-                                form={form}
-                                label='Directory'
-                                name='directory'
-                                path='directory'
-                                required={true}
-                            />
-                        </Grid.Column>
-                    </Grid.Row>
-                    <Grid.Row>
-                        <Grid.Column>
-                            <ToggleForm
-                                form={form}
-                                label={downloadMissingDataLabel}
-                                path='download_missing_data'
-                            />
-                        </Grid.Column>
-                    </Grid.Row>
+                <Grid>
+                    <Grid.Col span={{base: 12, sm: 6}}>
+                        <InputForm
+                            form={form}
+                            label="Channel Name"
+                            name="name"
+                            placeholder="Short Channel Name"
+                            required={true}
+                        />
+                    </Grid.Col>
+                    <Grid.Col span={{base: 12, sm: 6}}>
+                        <DestinationForm
+                            form={form}
+                            label='Directory'
+                            name='directory'
+                            path='directory'
+                            required={true}
+                        />
+                    </Grid.Col>
+                    <Grid.Col span={12}>
+                        <ToggleForm
+                            form={form}
+                            label={downloadMissingDataLabel}
+                            path='download_missing_data'
+                        />
+                    </Grid.Col>
                     {messageRow}
-                    <Grid.Row>
-                        <Grid.Column width={8}>
-                            <DownloadTagsSelector
-                                form={form}
-                                limit={1}
-                                path='tag_name'
-                                name='tag_name'
-                            />
-                        </Grid.Column>
-                        <Grid.Column>
+                    <Grid.Col span={{base: 12, sm: 8}}>
+                        <DownloadTagsSelector
+                            form={form}
+                            limit={1}
+                            path='tag_name'
+                            name='tag_name'
+                        />
+                    </Grid.Col>
+                    <Grid.Col span={{base: 12, sm: 4}}>
+                        <div style={{textAlign: 'right'}}>
                             <APIButton
-                                color='violet'
+                                role='primary'
                                 size='big'
-                                floated='right'
                                 onClick={handleSubmit}
                                 disabled={form.disabled}
                                 obeyWROLMode={true}
                             >Save</APIButton>
-                        </Grid.Column>
-                    </Grid.Row>
+                        </div>
+                    </Grid.Col>
                 </Grid>
-            </Form>
-        </Segment>
+            </form>
+        </Panel>
     </>;
 }
 
@@ -534,37 +500,28 @@ export function ChannelsPage() {
     }, {enableOnFormTags: false});
 
     // Header section matching DomainsPage pattern
-    const header = <div style={{marginBottom: '1em'}}>
-        <Grid stackable columns={2}>
-            <Grid.Row>
-                <Grid.Column>
-                    <SearchInput
-                        placeholder='Name filter...'
-                        size='large'
-                        searchStr={searchStr}
-                        disabled={!Array.isArray(channels) || channels.length === 0}
-                        onClear={() => setSearchStr('')}
-                        onChange={setSearchStr}
-                        onSubmit={null}
-                        inputRef={searchInputRef}
-                    />
-                </Grid.Column>
-                <Grid.Column textAlign='right'>
-                    <Link to='/videos/channel/new'>
-                        <Button secondary>New Channel</Button>
-                    </Link>
-                </Grid.Column>
-            </Grid.Row>
-        </Grid>
-    </div>;
+    const header = <Group justify='space-between' align='flex-end' wrap='wrap' mb='1em'>
+        <SearchInput
+            placeholder='Name filter...'
+            size='large'
+            searchStr={searchStr}
+            disabled={!Array.isArray(channels) || channels.length === 0}
+            onClear={() => setSearchStr('')}
+            onChange={setSearchStr}
+            onSubmit={null}
+            inputRef={searchInputRef}
+        />
+        <Link to='/videos/channel/new'>
+            <Button role='primary'>New Channel</Button>
+        </Link>
+    </Group>;
 
     // Empty state
     if (channels && channels.length === 0) {
         return <>
             {header}
-            <Message>
-                <Message.Header>No channels exist yet!</Message.Header>
-                <Message.Content><Link to='/videos/channel/new'>Create one.</Link></Message.Content>
+            <Message title='No channels exist yet!'>
+                <Link to='/videos/channel/new'>Create one.</Link>
             </Message>
         </>;
     }
diff --git a/app/src/components/Common.js b/app/src/components/Common.js
index 1d79990d..ed62c693 100644
--- a/app/src/components/Common.js
+++ b/app/src/components/Common.js
@@ -175,9 +175,6 @@ export function isoDatetimeToString(dt, time = false) {
 }
 
 export function CardLink({to, newTab = false, ...props}) {
-    const {t} = useContext(ThemeContext);
-    props = {...props, ...t};
-
     props = newTab === true ? {...props, target: '_blank', rel: 'noopener noreferrer'} : props;
     return <Link to={to} className="no-link-underscore card-link" {...props}>
         {props.children}
@@ -185,13 +182,11 @@ export function CardLink({to, newTab = false, ...props}) {
 }
 
 export function ExternalCardLink({to, children, ...props}) {
-    const {t} = useContext(ThemeContext);
     return <a
         href={to}
         target='_blank'
         rel='noopener noreferrer'
         className='no-link-underscore card-link'
-        {...t}
         {...props}
     >
         {children}
@@ -199,10 +194,9 @@ export function ExternalCardLink({to, children, ...props}) {
 }
 
 export function PreviewLink({file, children, className, ...props}) {
-    const {t} = useContext(ThemeContext);
     const {setPreviewFile} = React.useContext(FilePreviewContext);
     className = className ? `clickable ${className}` : `clickable `;
-    return <span className={className} onClick={() => setPreviewFile(file)} {...props} {...t}>
+    return <span className={className} onClick={() => setPreviewFile(file)} {...props}>
         {children}
     </span>
 }
diff --git a/app/src/components/Docs.js b/app/src/components/Docs.js
index 8083fea1..881d6731 100644
--- a/app/src/components/Docs.js
+++ b/app/src/components/Docs.js
@@ -1,8 +1,7 @@
-import React, {useContext, useEffect, useState} from 'react';
+import React, {useEffect, useState} from 'react';
 import {Link, Route, Routes, useLocation, useNavigate, useParams, useSearchParams} from "react-router";
-import {Grid, Icon as SIcon, Loader, StatisticLabel, StatisticValue} from "semantic-ui-react";
 import {deleteFileGroups, getDocStatistics, tagFileGroup, untagFileGroup} from "../api";
-import {Media, ThemeContext} from "../contexts/contexts";
+import {Media} from "../contexts/contexts";
 import {
     APIButton,
     BackButton,
@@ -18,7 +17,7 @@ import {
     toLocaleString,
     useTitle
 } from "./Common";
-import {Button, darkTheme, Header, Icon, Segment, Statistic, Tab} from "./Theme";
+import {Button, ButtonGroup, Group, Header, Loading, Panel, Statistic, StatisticGroup, Tabs} from "./ui";
 import {BulkTagModal} from "./BulkTagModal";
 import {TaggedDeleteConfirmModal} from "./TaggedDeleteConfirmModal";
 import {DeepSearchHint, docMimetypeFilterOptions, FilesView, SearchControlBar} from "./Files";
@@ -88,15 +87,15 @@ function DocsPage() {
         <Button color='violet' disabled={_.isEmpty(selectedDocs)}
                 onClick={() => setBulkTagOpen(true)}>Tag</Button>
         <APIButton
-            color='red'
+            role='danger'
             disabled={_.isEmpty(selectedDocs)}
             confirmButton='Delete'
             confirmContent='Are you sure you want to delete these documents? This cannot be undone.'
             onClick={() => onDelete(false)}
             obeyWROLMode={true}
         >Delete</APIButton>
-        <Button color='grey' onClick={invertSelection} disabled={_.isEmpty(docs)}>Invert</Button>
-        <Button color='yellow' onClick={clearSelection}
+        <Button role='cancel' onClick={invertSelection} disabled={_.isEmpty(docs)}>Invert</Button>
+        <Button role='cancel' onClick={clearSelection}
                 disabled={_.isEmpty(docs) || _.isEmpty(selectedDocs)}>Clear</Button>
         <BulkTagModal
             open={bulkTagOpen}
@@ -159,7 +158,6 @@ function DocPage() {
     const {fileGroupId} = useParams();
     const navigate = useNavigate();
     const {docFile, doc, fetchDoc} = useDoc(parseInt(fileGroupId));
-    const {theme} = useContext(ThemeContext);
     const [searchParams] = useSearchParams();
     const [taggedFileGroups, setTaggedFileGroups] = useState(null);
     // Deep-link params: `loc` = EPUB spine index, `page` = PDF page, `q` = search term.
@@ -173,7 +171,7 @@ function DocPage() {
     const [selectedFileIndex, setSelectedFileIndex] = useState(0);
 
     if (docFile === null) {
-        return <Segment><Loader active/></Segment>;
+        return <Panel><Loading/></Panel>;
     }
     if (docFile === undefined) {
         return <>
@@ -282,72 +280,63 @@ function DocPage() {
         return mt.split('/').pop().toUpperCase();
     };
 
-    // About pane.
-    const aboutPane = {
-        menuItem: 'About', render: () => <Tab.Pane>
-            {doc && doc.description && <>
-                <Header as='h3'>Description</Header>
-                <p>{doc.description}</p>
-            </>}
+    // About tab.
+    const aboutTab = <>
+        {doc && doc.description && <>
+            <Header as='h3'>Description</Header>
+            <p>{doc.description}</p>
+        </>}
 
-            {doc && doc.publisher && <>
-                <Header as='h3'>Publisher</Header>
-                <p>{doc.publisher}</p>
-            </>}
+        {doc && doc.publisher && <>
+            <Header as='h3'>Publisher</Header>
+            <p>{doc.publisher}</p>
+        </>}
 
-            {doc && doc.language && <>
-                <Header as='h3'>Language</Header>
-                <p>{doc.language}</p>
-            </>}
+        {doc && doc.language && <>
+            <Header as='h3'>Language</Header>
+            <p>{doc.language}</p>
+        </>}
 
-            {doc && doc.subject && <>
-                <Header as='h3'>Subject</Header>
-                <p><Link to={`/docs?subject=${encodeURIComponent(doc.subject)}`}>{doc.subject}</Link></p>
-            </>}
+        {doc && doc.subject && <>
+            <Header as='h3'>Subject</Header>
+            <p><Link to={`/docs?subject=${encodeURIComponent(doc.subject)}`}>{doc.subject}</Link></p>
+        </>}
 
-            {doc && doc.page_count && <>
-                <Header as='h3'>Page Count</Header>
-                <p>{doc.page_count}</p>
-            </>}
+        {doc && doc.page_count && <>
+            <Header as='h3'>Page Count</Header>
+            <p>{doc.page_count}</p>
+        </>}
 
-            <Header as='h3'>Size</Header>
-            <p>{humanFileSize(size)}</p>
-        </Tab.Pane>
-    };
+        <Header as='h3'>Size</Header>
+        <p>{humanFileSize(size)}</p>
+    </>;
 
-    // Files pane.
+    // Files tab.
     const tableStyle = {width: '100%', borderCollapse: 'separate', borderSpacing: '0 0.7em'};
     const labelStyle = {whiteSpace: 'nowrap', paddingRight: '1.5em', verticalAlign: 'top'};
-    const filesPane = {
-        menuItem: 'Files', render: () => <Tab.Pane>
-            <table style={tableStyle}>
-                <tbody>
-                {docFile.files && docFile.files.map((file, idx) =>
-                    <tr key={idx}>
-                        <td style={labelStyle}>
-                            <strong>{file.path.split('.').pop().toUpperCase()}</strong>
-                        </td>
-                        <td>
-                            <PreviewPath path={file.path} mimetype={file.mimetype} taggable={false}>
-                                {file.path}
-                            </PreviewPath>
-                            {file.size && <span style={{marginLeft: '1em', color: 'grey'}}>
-                                ({humanFileSize(file.size)})
-                            </span>}
-                        </td>
-                    </tr>
-                )}
-                <tr>
-                    <td style={labelStyle}><strong>Directory</strong></td>
-                    <td><DirectoryLink path={directory}/></td>
-                </tr>
-                </tbody>
-            </table>
-        </Tab.Pane>
-    };
-
-    const tabPanes = [aboutPane, filesPane];
-    const tabMenu = theme === darkTheme ? {inverted: true, attached: true} : {attached: true};
+    const filesTab = <table style={tableStyle}>
+        <tbody>
+        {docFile.files && docFile.files.map((file, idx) =>
+            <tr key={idx}>
+                <td style={labelStyle}>
+                    <strong>{file.path.split('.').pop().toUpperCase()}</strong>
+                </td>
+                <td>
+                    <PreviewPath path={file.path} mimetype={file.mimetype} taggable={false}>
+                        {file.path}
+                    </PreviewPath>
+                    {file.size && <span style={{marginLeft: '1em', color: 'var(--muted)'}}>
+                        ({humanFileSize(file.size)})
+                    </span>}
+                </td>
+            </tr>
+        )}
+        <tr>
+            <td style={labelStyle}><strong>Directory</strong></td>
+            <td><DirectoryLink path={directory}/></td>
+        </tr>
+        </tbody>
+    </table>;
 
     return <>
         <BackButton/>
@@ -358,56 +347,51 @@ function DocPage() {
             <iframe
                 src={embedUrl}
                 title={docFile.title || docFile.name}
-                style={{width: '100%', height: '80vh', border: '1px solid #ccc', borderRadius: '4px'}}
+                style={{width: '100%', height: '80vh', border: '1px solid var(--border)'}}
             />
         </div>}
 
-        <Segment>
+        <Panel>
             <Header as='h2'>{docFile.title || docFile.name}</Header>
 
             {docFile.author && <Header as='h3'>
                 Author: <Link to={`/docs?author=${encodeURIComponent(docFile.author)}`}>{docFile.author}</Link>
             </Header>}
 
-            <Grid columns={2} stackable>
-                <Grid.Row>
-                    <Grid.Column>
-                        <Header as='h4'>Format: {formatLabel()}{doc && doc.page_count && ` (${doc.page_count} pages)`}</Header>
-                    </Grid.Column>
-                    {publishedDatetimeString && <Grid.Column>
-                        <Header as='h4'>Published: {publishedDatetimeString}</Header>
-                    </Grid.Column>}
-                </Grid.Row>
-            </Grid>
+            <Group gap='xl' wrap='wrap'>
+                <Header as='h4'>Format: {formatLabel()}{doc && doc.page_count && ` (${doc.page_count} pages)`}</Header>
+                {publishedDatetimeString && <Header as='h4'>Published: {publishedDatetimeString}</Header>}
+            </Group>
 
             {(() => {
-                const formatButtons = viewableFiles.length > 1 ? <Button.Group>
+                const formatButtons = viewableFiles.length > 1 ? <ButtonGroup>
                     {viewableFiles.map((file, idx) => {
                         const mt = file.mimetype || '';
                         let btnColor;
                         if (mt.startsWith('application/epub')) btnColor = 'yellow';
                         else if (mt === 'application/pdf') btnColor = 'red';
+                        const isSelected = idx === selectedFileIndex;
                         return <Button
                             key={file.path}
-                            active={idx === selectedFileIndex}
                             onClick={() => setSelectedFileIndex(idx)}
-                            color={idx === selectedFileIndex ? btnColor : undefined}
-                            basic={idx !== selectedFileIndex}
+                            color={isSelected ? btnColor : undefined}
+                            variant={isSelected ? 'filled' : 'default'}
                         >
                             {formatLabel(file.mimetype)}
                         </Button>;
                     })}
-                </Button.Group> : null;
+                </ButtonGroup> : null;
 
                 const actionButtons = <>
-                    {openUrl && <Button as='a' href={openUrl} target='_blank' rel='noreferrer' color='violet'>
-                        <SIcon name='expand arrows alternate'/> Open
+                    {openUrl && <Button component='a' href={openUrl} target='_blank' rel='noreferrer'
+                                        color='violet' icon='expand arrows alternate'>
+                        Open
                     </Button>}
-                    {downloadUrl && <Button as='a' href={downloadUrl}>
-                        <SIcon name='download'/> Download
+                    {downloadUrl && <Button component='a' href={downloadUrl} icon='download'>
+                        Download
                     </Button>}
                     <APIButton
-                        color='red'
+                        role='danger'
                         confirmContent='Are you sure you want to delete this document? All files will be deleted.'
                         confirmButton='Delete'
                         onClick={() => handleDelete(false)}
@@ -431,13 +415,20 @@ function DocPage() {
                     </Media>
                 </>;
             })()}
-        </Segment>
+        </Panel>
 
-        <Segment>
+        <Panel>
             <TagsSelector selectedTagNames={docFile.tags} onAdd={localAddTag} onRemove={localRemoveTag}/>
-        </Segment>
+        </Panel>
 
-        <Tab menu={tabMenu} panes={tabPanes}/>
+        <Tabs defaultValue='about'>
+            <Tabs.List>
+                <Tabs.Tab value='about'>About</Tabs.Tab>
+                <Tabs.Tab value='files'>Files</Tabs.Tab>
+            </Tabs.List>
+            <Tabs.Panel value='about' pt='md'>{aboutTab}</Tabs.Panel>
+            <Tabs.Panel value='files' pt='md'>{filesTab}</Tabs.Panel>
+        </Tabs>
 
         <TaggedDeleteConfirmModal
             open={taggedFileGroups !== null}
@@ -479,22 +470,16 @@ function AuthorsPage() {
     const searchInputRef = React.useRef();
 
     const header = <div style={{marginBottom: '1em'}}>
-        <Grid stackable columns={2}>
-            <Grid.Row>
-                <Grid.Column>
-                    <SearchInput
-                        placeholder='Author filter...'
-                        size='large'
-                        searchStr={searchStr}
-                        disabled={!Array.isArray(authors) || authors.length === 0}
-                        onClear={() => setSearchStr('')}
-                        onChange={setSearchStr}
-                        onSubmit={null}
-                        inputRef={searchInputRef}
-                    />
-                </Grid.Column>
-            </Grid.Row>
-        </Grid>
+        <SearchInput
+            placeholder='Author filter...'
+            size='large'
+            searchStr={searchStr}
+            disabled={!Array.isArray(authors) || authors.length === 0}
+            onClear={() => setSearchStr('')}
+            onChange={setSearchStr}
+            onSubmit={null}
+            inputRef={searchInputRef}
+        />
     </div>;
 
     return <>
@@ -517,22 +502,16 @@ function SubjectsPage() {
     const searchInputRef = React.useRef();
 
     const header = <div style={{marginBottom: '1em'}}>
-        <Grid stackable columns={2}>
-            <Grid.Row>
-                <Grid.Column>
-                    <SearchInput
-                        placeholder='Subject filter...'
-                        size='large'
-                        searchStr={searchStr}
-                        disabled={!Array.isArray(subjects) || subjects.length === 0}
-                        onClear={() => setSearchStr('')}
-                        onChange={setSearchStr}
-                        onSubmit={null}
-                        inputRef={searchInputRef}
-                    />
-                </Grid.Column>
-            </Grid.Row>
-        </Grid>
+        <SearchInput
+            placeholder='Subject filter...'
+            size='large'
+            searchStr={searchStr}
+            disabled={!Array.isArray(subjects) || subjects.length === 0}
+            onClear={() => setSearchStr('')}
+            onChange={setSearchStr}
+            onSubmit={null}
+            inputRef={searchInputRef}
+        />
     </div>;
 
     return <>
@@ -568,45 +547,24 @@ function DocsStatisticsPage() {
     }, []);
 
     if (statistics === null) {
-        return <Loader active inline='centered'/>;
+        return <Loading/>;
     }
     if (statistics === undefined) {
         return <ErrorMessage>Unable to fetch Doc Statistics</ErrorMessage>;
     }
 
-    return <Segment>
-        <Header as='h1' textAlign='center'>Documents</Header>
-        <Statistic.Group>
-            <Statistic style={{margin: '2em'}}>
-                <StatisticValue>{toLocaleString(statistics.doc_count)}</StatisticValue>
-                <StatisticLabel>Documents</StatisticLabel>
-            </Statistic>
-            <Statistic style={{margin: '2em'}}>
-                <StatisticValue>{toLocaleString(statistics.epub_count)}</StatisticValue>
-                <StatisticLabel>eBooks</StatisticLabel>
-            </Statistic>
-            <Statistic style={{margin: '2em'}}>
-                <StatisticValue>{toLocaleString(statistics.pdf_count)}</StatisticValue>
-                <StatisticLabel>PDFs</StatisticLabel>
-            </Statistic>
-            <Statistic style={{margin: '2em'}}>
-                <StatisticValue>{toLocaleString(statistics.other_count)}</StatisticValue>
-                <StatisticLabel>Other</StatisticLabel>
-            </Statistic>
-            <Statistic style={{margin: '2em'}}>
-                <StatisticValue>{humanFileSize(statistics.total_size)}</StatisticValue>
-                <StatisticLabel>Total Size</StatisticLabel>
-            </Statistic>
-            <Statistic style={{margin: '2em'}}>
-                <StatisticValue>{toLocaleString(statistics.author_count)}</StatisticValue>
-                <StatisticLabel>Authors</StatisticLabel>
-            </Statistic>
-            <Statistic style={{margin: '2em'}}>
-                <StatisticValue>{toLocaleString(statistics.subject_count)}</StatisticValue>
-                <StatisticLabel>Subjects</StatisticLabel>
-            </Statistic>
-        </Statistic.Group>
-    </Segment>;
+    return <Panel>
+        <Header as='h1' style={{textAlign: 'center'}}>Documents</Header>
+        <StatisticGroup>
+            <Statistic value={toLocaleString(statistics.doc_count)} label='Documents'/>
+            <Statistic value={toLocaleString(statistics.epub_count)} label='eBooks'/>
+            <Statistic value={toLocaleString(statistics.pdf_count)} label='PDFs'/>
+            <Statistic value={toLocaleString(statistics.other_count)} label='Other'/>
+            <Statistic value={humanFileSize(statistics.total_size)} label='Total Size'/>
+            <Statistic value={toLocaleString(statistics.author_count)} label='Authors'/>
+            <Statistic value={toLocaleString(statistics.subject_count)} label='Subjects'/>
+        </StatisticGroup>
+    </Panel>;
 }
 
 export function DocsRoute() {
diff --git a/app/src/components/FileBrowser.js b/app/src/components/FileBrowser.js
index d69f2150..d43bc1c1 100644
--- a/app/src/components/FileBrowser.js
+++ b/app/src/components/FileBrowser.js
@@ -1,17 +1,20 @@
-import {Button, Header, Icon, Modal, Placeholder, Progress, Segment, Table} from "./Theme";
 import {
+    ActionInput,
+    Button,
     Checkbox,
-    Form,
-    Grid,
-    IconGroup,
-    Input,
-    PlaceholderLine,
-    TableBody,
-    TableCell,
-    TableHeader,
-    TableHeaderCell,
-    TableRow
-} from "semantic-ui-react";
+    Header,
+    Icon,
+    IconButton,
+    IconStack,
+    Modal,
+    Panel,
+    Placeholder,
+    Progress,
+    Skeleton,
+    Stack,
+    Table,
+    TextInput,
+} from "./ui";
 import {
     APIButton,
     DirectorySearch,
@@ -23,6 +26,7 @@ import {
     useIsIgnoredDirectory
 } from "./Common";
 import React, {useContext, useEffect, useState} from "react";
+import {IconArrowsMove, IconChevronsUp, IconCursorText, IconTags} from "@tabler/icons-react";
 import {useDropzone} from "react-dropzone";
 import {useHotkeys} from "react-hotkeys-hook";
 import {deleteFile, ignoreDirectory, makeDirectory, movePaths, renamePath, unignoreDirectory} from "../api";
@@ -111,23 +115,28 @@ function Folder({folder, onFolderClick, sortData, onFileClick, disabled, loading
     const isLoading = loadingFolders && loadingFolders.has(path);
     const depth = (path.match(/\//g) || []).length;
 
-    const f = <TableRow
+    const f = <Table.Row
         key={path}
-        disabled={isLoading || disabled}
         className={dragClass}
+        style={(isLoading || disabled) ? {opacity: 0.5, pointerEvents: 'none'} : undefined}
         onMouseDown={(e) => handleDragStart(path, e)}
         onMouseEnter={() => handleDragMove(path)}
     >
-        <TableCell collapsing>
+        <Table.Cell style={{width: '1%', whiteSpace: 'nowrap'}}>
             <Checkbox checked={showAsSelected} onChange={() => onSelect(folder['path'])}/>
-        </TableCell>
-        <TableCell onClick={() => shouldAllowClick() && onFolderClick(path)} className='file-path' colSpan={2} disabled={is_empty}>
+        </Table.Cell>
+        <Table.Cell
+            onClick={() => shouldAllowClick() && onFolderClick(path)}
+            className='file-path'
+            colSpan={2}
+            style={is_empty ? {opacity: 0.5} : undefined}
+        >
             {depthIndentation(pathWithNoTrailingSlash)}
             {is_empty ? <Icon name='folder outline'/> : <Icon name='folder'/>}
             {ignored && <Icon name='eye slash' color='red'/>}
             {name}
-        </TableCell>
-    </TableRow>;
+        </Table.Cell>
+    </Table.Row>;
     if (children) {
         // Folder has children, recursively display them.
         children = sortData(children);
@@ -164,27 +173,27 @@ function File({file, onFileClick, disabled}) {
     const showAsSelected = (isInSelectedPaths && !isDragDeselecting) || isDragSelecting;
     // Visual highlight class
     const dragClass = isDragSelecting ? 'drag-selecting' : (isDragDeselecting ? 'drag-deselecting' : '');
-    return <TableRow
+    return <Table.Row
         key={path}
-        disabled={disabled}
         className={dragClass}
+        style={disabled ? {opacity: 0.5, pointerEvents: 'none'} : undefined}
         onMouseDown={(e) => handleDragStart(path, e)}
         onMouseEnter={() => handleDragMove(path)}
     >
-        <TableCell collapsing>
+        <Table.Cell style={{width: '1%', whiteSpace: 'nowrap'}}>
             <Checkbox checked={showAsSelected} onChange={() => onSelect(path)}/>
-        </TableCell>
-        <TableCell onClick={() => shouldAllowClick() && onFileClick(file)} className='file-path'>
+        </Table.Cell>
+        <Table.Cell onClick={() => shouldAllowClick() && onFileClick(file)} className='file-path'>
             {depthIndentation(path)}
             <FileRowTagIcon file={file}/>
             {/*null size to make icon the correct size*/}
             <FileIcon file={file} size={null}/>
             {pathName(path)}
-        </TableCell>
-        <TableCell collapsing textAlign='right'>
+        </Table.Cell>
+        <Table.Cell numeric style={{width: '1%', whiteSpace: 'nowrap'}}>
             {humanFileSize(size)}
-        </TableCell>
-    </TableRow>
+        </Table.Cell>
+    </Table.Row>
 }
 
 function Path({path, onFolderClick, onFileClick, sortData, disabled, loadingFolders}) {
@@ -209,17 +218,15 @@ function Path({path, onFolderClick, onFileClick, sortData, disabled, loadingFold
 function SkeletonFileRow({depth}) {
     const indentation = '\xa0\xa0\xa0\xa0'.repeat(depth);
     return (
-        <TableRow>
-            <TableCell collapsing>
+        <Table.Row>
+            <Table.Cell style={{width: '1%', whiteSpace: 'nowrap'}}>
                 <Checkbox disabled/>
-            </TableCell>
-            <TableCell className='file-path' colSpan={2}>
+            </Table.Cell>
+            <Table.Cell className='file-path' colSpan={2}>
                 {indentation}
-                <Placeholder style={{display: 'inline-block', width: '200px', marginLeft: '0.5em'}}>
-                    <PlaceholderLine/>
-                </Placeholder>
-            </TableCell>
-        </TableRow>
+                <Skeleton height={12} width={200} radius={0} animate style={{display: 'inline-block', marginLeft: '0.5em'}}/>
+            </Table.Cell>
+        </Table.Row>
     );
 }
 
@@ -387,28 +394,26 @@ export function FileBrowser() {
     const [footerRef, footerWidth] = useElementWidth();
     // Expand icon-only buttons to include labels once the footer is wide enough to fit them.
     const showLabels = footerWidth >= FOOTER_LABELS_MIN_WIDTH;
-    // Semantic UI renders a labeled icon button when `content` and `labelPosition` are set, else icon-only.
-    const labelProps = (content) => showLabels ? {content, labelPosition: 'left'} : {};
+    // Show a label alongside the icon once there's room; otherwise the icon carries the meaning alone.
+    const label = (text) => showLabels ? text : null;
 
     const footerClassName = `sticky-footer ${inverted}`;
     const footer = <div className={footerClassName} ref={footerRef}>
         <FilesRefreshButton paths={selectedPaths} showLabel={showLabels}/>
         <APIButton
             icon='trash'
-            color='red'
+            role='danger'
             confirmContent='Are you sure you want to delete these files?'
             confirmButton='Delete'
             onClick={onDelete}
             disabled={selectedPathsCount === 0}
             obeyWROLMode={true}
-            {...labelProps('Delete')}
-        />
-        <Button icon='text cursor'
+        >{label('Delete')}</APIButton>
+        <Button icon={IconCursorText}
                 color='yellow'
                 onClick={() => setRenameOpen(true)}
                 disabled={wrolModeEnabled || selectedPathsCount !== 1}
-                {...labelProps('Rename')}
-        />
+        >{label('Rename')}</Button>
         {selectedPathsCount === 1 ?
             <RenameModal
                 open={renameOpen}
@@ -417,12 +422,11 @@ export function FileBrowser() {
                 path={selectedPaths[0]}
                 onSubmit={reset}
             /> : null}
-        <Button icon='move'
+        <Button icon={IconArrowsMove}
                 color='teal'
                 disabled={wrolModeEnabled || selectedPathsCount === 0}
                 onClick={() => setMoveOpen(true)}
-                {...labelProps('Move')}
-        />
+        >{label('Move')}</Button>
         {selectedPathsCount > 0 ?
             <MoveModal open={moveOpen}
                        onClose={() => setMoveOpen(false)}
@@ -435,10 +439,9 @@ export function FileBrowser() {
             disabled={wrolModeEnabled}
             style={{paddingLeft: '1em', paddingRight: showLabels ? '1em' : '0.8em'}}
         >
-            <IconGroup>
+            <IconStack corner={<Icon name='add'/>} label='New folder'>
                 <Icon name='folder'/>
-                <Icon corner name='add'/>
-            </IconGroup>
+            </IconStack>
             {showLabels ? <>&nbsp;New Folder</> : null}
         </Button>
         <MakeDirectoryModal
@@ -452,8 +455,7 @@ export function FileBrowser() {
             color='green'
             disabled={wrolModeEnabled || (selectedPathsCount > 0 && !singleDirectorySelected)}
             onClick={() => setUploadOpen(true)}
-            {...labelProps('Upload')}
-        />
+        >{label('Upload')}</Button>
         <FileBrowserUploadModal
             open={uploadOpen}
             onClose={() => setUploadOpen(false)}
@@ -465,8 +467,7 @@ export function FileBrowser() {
             icon={isDirectoryIgnored ? 'eye' : 'eye slash'}
             disabled={!singleDirectorySelected || wrolModeEnabled}
             onClick={() => setIgnoreDirectoryOpen(true)}
-            {...labelProps(isDirectoryIgnored ? 'Unignore' : 'Ignore')}
-        />
+        >{label(isDirectoryIgnored ? 'Unignore' : 'Ignore')}</Button>
         <IgnoreDirectoryModal
             open={ignoreDirectoryOpen}
             onClose={onIgnore}
@@ -476,11 +477,10 @@ export function FileBrowser() {
         />
         <Button
             color='violet'
-            icon='tags'
+            icon={IconTags}
             disabled={selectedPathsCount === 0}
             onClick={() => setBulkTagOpen(true)}
-            {...labelProps('Tag')}
-        />
+        >{label('Tag')}</Button>
         <BulkTagModal
             open={bulkTagOpen}
             onClose={() => setBulkTagOpen(false)}
@@ -536,10 +536,7 @@ export function FileBrowser() {
     );
 
     if (browseFiles === null) {
-        return <Placeholder>
-            <PlaceholderLine/>
-            <PlaceholderLine/>
-        </Placeholder>;
+        return <Placeholder lines={2}/>;
     } else if (browseFiles === undefined) {
         return <ErrorMessage>Could not fetch files</ErrorMessage>
     }
@@ -551,31 +548,29 @@ export function FileBrowser() {
         openFolders={openFolders}
     >
         <div className='file-browser-filter-container'>
-            <Input
-                icon='filter'
-                iconPosition='left'
+            <ActionInput
+                leftSection={<Icon name='filter'/>}
                 placeholder='Filter files...'
                 value={filterStr}
-                onChange={(e, {value}) => setFilterStr(value)}
+                onChange={(e) => setFilterStr(e.target.value)}
                 aria-label='Filter files'
                 className='file-browser-filter'
                 ref={filterInputRef}
-                action={<Button
+                action={<IconButton
                     icon='close'
                     type='button'
                     onClick={() => setFilterStr('')}
                     disabled={!filterStr}
                     className='search-clear'
-                    aria-label='Clear filter'
+                    label='Clear filter'
                 />}
             />
-            <Button
-                icon='angle double up'
+            <IconButton
+                icon={IconChevronsUp}
                 type='button'
                 onClick={onCollapseAll}
                 disabled={!openFolders || openFolders.length === 0}
-                title='Close all folders'
-                aria-label='Close all folders'
+                label='Close all folders'
                 style={{marginLeft: '0.5em'}}
             />
         </div>
@@ -598,7 +593,6 @@ function FileBrowserContent({browseFiles, headers, onFolderClick, setPreviewFile
     return (
         <div style={{marginBottom: '4em'}} className={containerClassName}>
             <SortableTable
-                tableProps={{striped: true}}
                 data={browseFiles}
                 tableHeaders={headers}
                 defaultSortColumn='path'
@@ -624,11 +618,8 @@ export function RenameModal({open, onClose, path, onSubmit, onPending}) {
     const [value, setValue] = React.useState(name);
     const disabled = value === name;
 
-    const handleInputChange = (e, props) => {
-        if (e) {
-            e.preventDefault();
-        }
-        setValue(props.value);
+    const handleInputChange = (e) => {
+        setValue(e.target.value);
     }
 
     const handleSubmit = async (e) => {
@@ -652,25 +643,31 @@ export function RenameModal({open, onClose, path, onSubmit, onPending}) {
         setValue(pathName(path));
     }, [path]);
 
-    return <Modal closeIcon
+    return <Modal
                   open={open}
                   onClose={onClose}
     >
         <Modal.Header>Rename: {name}</Modal.Header>
         <Modal.Content>
-            <Form onSubmit={handleSubmit}>
+            <form onSubmit={handleSubmit}>
                 <Header as='h4'>New Name</Header>
                 <pre>{parent ? parent + '/' : null}{value}</pre>
 
-                <Input fluid
+                <TextInput
                        autoFocus
                        label='Name'
                        value={value}
                        onChange={handleInputChange}
                 />
-            </Form>
+            </form>
         </Modal.Content>
         <Modal.Actions>
+            <Button
+                onClick={() => setValue(name)}
+                style={{marginRight: 'auto'}}
+            >
+                Reset
+            </Button>
             <Button
                 color='violet'
                 disabled={disabled}
@@ -678,12 +675,6 @@ export function RenameModal({open, onClose, path, onSubmit, onPending}) {
             >
                 Rename
             </Button>
-            <Button
-                onClick={() => setValue(name)}
-                floated='left'
-            >
-                Reset
-            </Button>
         </Modal.Actions>
     </Modal>
 }
@@ -710,47 +701,47 @@ export function MoveModal({open, paths, onClose, onSubmit}) {
         }
     }
 
-    const fileCell = i => <TableCell>
+    const fileCell = i => <Table.Cell>
         <pre style={{marginTop: 0, marginBottom: 0}}>{i}</pre>
-    </TableCell>;
+    </Table.Cell>;
 
-    const destinationRows = paths.map(i => <TableRow key={i}>
+    const destinationRows = paths.map(i => <Table.Row key={i}>
         {fileCell(i)}
         {destination ? fileCell(destination + '/' + pathName(i)) : fileCell(pathName(i))}
-    </TableRow>);
+    </Table.Row>);
 
-    return <Modal closeIcon
+    return <Modal
                   onClose={onClose}
                   open={open}
     >
         <Modal.Header>Move Files/Directories</Modal.Header>
         <Modal.Content>
             <p>Search for a directory to move your files into:</p>
-            <DirectorySearch onSelect={handleDirectory} disabled={pending} input={{autoFocus: true}}/>
+            <DirectorySearch onSelect={handleDirectory} disabled={pending} autoFocus/>
 
             <Table>
-                <TableHeader>
-                    <TableRow>
-                        <TableHeaderCell>Source</TableHeaderCell>
-                        <TableHeaderCell>Destination</TableHeaderCell>
-                    </TableRow>
-                </TableHeader>
-                <TableBody>
+                <Table.Header>
+                    <Table.Row>
+                        <Table.HeaderCell>Source</Table.HeaderCell>
+                        <Table.HeaderCell>Destination</Table.HeaderCell>
+                    </Table.Row>
+                </Table.Header>
+                <Table.Body>
                     {destinationRows}
-                </TableBody>
+                </Table.Body>
             </Table>
         </Modal.Content>
         <Modal.Actions>
+            <Button
+                onClick={() => setDestination(null)}
+                style={{marginRight: 'auto'}}
+                disabled={pending}
+            >Reset</Button>
             <Button
                 color='violet'
                 onClick={handleMove}
                 disabled={pending}
             >Move</Button>
-            <Button
-                onClick={() => setDestination(null)}
-                floated='left'
-                disabled={pending}
-            >Reset</Button>
         </Modal.Actions>
     </Modal>
 }
@@ -779,20 +770,20 @@ export function IgnoreDirectoryModal({open, onClose, onSubmit, directory, ignore
     const content = ignored ?
         'Remove ignore of the following directory?  You must refresh your files after this.'
         : 'Ignore the following directory? The files within will not be indexed and will not show in search results.';
-    let submitButton = <Button primary
+    let submitButton = <Button role='primary'
                                disabled={pending}
                                onClick={handleIgnore}
     >{ignored ? 'Un-ignore' : 'Ignore'}</Button>;
 
-    return <Modal closeIcon open={open} onClose={onClose}>
+    return <Modal open={open} onClose={onClose}>
         <Modal.Header>{header}</Modal.Header>
         <Modal.Content>
             {content}
             <pre>{mediaDirectory}/{directory}</pre>
         </Modal.Content>
         <Modal.Actions>
+            <Button role='cancel' style={{marginRight: 'auto'}} onClick={onClose}>Close</Button>
             {submitButton}
-            <Button secondary floated='left' onClick={onClose}>Close</Button>
         </Modal.Actions>
     </Modal>
 }
@@ -801,11 +792,8 @@ export function MakeDirectoryModal({open, onClose, parent, onSubmit}) {
     const [value, setValue] = useState('');
     const mediaDirectory = useMediaDirectory();
 
-    const handleInputChange = (e, props) => {
-        if (e) {
-            e.preventDefault();
-        }
-        setValue(props.value);
+    const handleInputChange = (e) => {
+        setValue(e.target.value);
     }
 
     const handleSubmit = async (e) => {
@@ -824,18 +812,18 @@ export function MakeDirectoryModal({open, onClose, parent, onSubmit}) {
         }
     }
 
-    return <Modal closeIcon open={open} onClose={onClose}>
+    return <Modal open={open} onClose={onClose}>
         <Modal.Header>Make Directory</Modal.Header>
         <Modal.Content>
-            <Form onSubmit={handleSubmit}>
+            <form onSubmit={handleSubmit}>
                 <pre>{mediaDirectory}/{parent}{value}</pre>
-                <Input fluid
+                <TextInput
                        autoFocus
                        label='Name'
                        value={value}
                        onChange={handleInputChange}
                 />
-            </Form>
+            </form>
         </Modal.Content>
         <Modal.Actions>
             <Button color='violet' onClick={handleSubmit}>Create</Button>
@@ -845,7 +833,6 @@ export function MakeDirectoryModal({open, onClose, parent, onSubmit}) {
 
 export function FileBrowserUploadModal({open, onClose, destination, onComplete}) {
     const mediaDirectory = useMediaDirectory();
-    const {t} = React.useContext(ThemeContext);
 
     const {
         setFiles,
@@ -909,27 +896,22 @@ export function FileBrowserUploadModal({open, onClose, destination, onComplete})
                 color = 'orange';
                 statusString = 'Already Exists:';
             }
-            let indicating = status === 'pending';
 
-            return <Grid.Row key={name}>
-                <Grid.Column mobile={3} tablet={2} computer={1}>
-                    <Icon name={mimetypeIconName(type, name.toLowerCase())} size='big'/>
-                </Grid.Column>
-                <Grid.Column mobile={13} tablet={14} computer={15}>
-                    <Progress progress indicating={indicating} percent={percent} color={color}>
-                        <p {...t}>{statusString} {name}</p>
-                    </Progress>
-                </Grid.Column>
-            </Grid.Row>
+            return <div key={name} style={{display: 'flex', alignItems: 'center', gap: '0.75em'}}>
+                <Icon name={mimetypeIconName(type, name.toLowerCase())} size='large'/>
+                <div style={{flex: 1}}>
+                    <Progress percent={percent} color={color} label={`${statusString} ${name}`}/>
+                </div>
+            </div>
         })
     }
 
     const displayPath = destination ? `${mediaDirectory}/${destination}` : mediaDirectory;
 
-    return <Modal closeIcon open={open} onClose={handleClose} size='large'>
+    return <Modal open={open} onClose={handleClose} size='large'>
         <Modal.Header>Upload to: {displayPath}</Modal.Header>
         <Modal.Content>
-            <Form>
+            <form onSubmit={e => e.preventDefault()}>
                 {tagsSelector}
                 <div style={{marginTop: '1em'}}>
                 <Toggle
@@ -939,49 +921,27 @@ export function FileBrowserUploadModal({open, onClose, destination, onComplete})
                     disabled={inProgress}
                 />
                 </div>
-            </Form>
+            </form>
 
-            <Segment>
-                <Grid columns={1}>
-                    <Grid.Row>
-                        <Grid.Column style={{padding: '1em'}}>
-                            <Form>
-                                <div {...getRootProps()}>
-                                    <input {...getInputProps()}/>
-                                    <Grid textAlign='center'>
-                                        <Grid.Row>
-                                            <Grid.Column>
-                                                <Header icon>
-                                                    <Icon name='file text'/>
-                                                    Click here, or drop files here to upload
-                                                </Header>
-                                            </Grid.Column>
-                                        </Grid.Row>
-                                    </Grid>
-                                </div>
-                            </Form>
-                        </Grid.Column>
-                    </Grid.Row>
-                </Grid>
-            </Segment>
+            <Panel style={{marginTop: '1em', padding: '1em'}}>
+                <div {...getRootProps()} style={{cursor: 'pointer', textAlign: 'center'}}>
+                    <input {...getInputProps()}/>
+                    <Header as='h4' icon='file text'>Click here, or drop files here to upload</Header>
+                </div>
+            </Panel>
 
-            <Grid>
-                <Grid.Row columns={1}>
-                    <Grid.Column>
-                        {progresses && Object.keys(progresses).length > 1 && <Progress progress
-                                                                                       percent={overallProgress}
-                                                                                       color='blue'
-                                                                                       label='Overall Progress'
-                        />}
-                    </Grid.Column>
-                </Grid.Row>
-            </Grid>
-            <Grid columns={2}>
+            {progresses && Object.keys(progresses).length > 1 &&
+                <div style={{marginTop: '1em'}}>
+                    <Progress percent={overallProgress} color='blue' label='Overall Progress'/>
+                </div>}
+
+            <Stack gap={8} style={{marginTop: '1em'}}>
                 {progressBars}
-            </Grid>
+            </Stack>
         </Modal.Content>
         <Modal.Actions>
             <Button
+                role='cancel'
                 onClick={handleClose}
                 disabled={inProgress}
             >
diff --git a/app/src/components/FileBrowser.test.js b/app/src/components/FileBrowser.test.js
index 9ba2b6fa..0a937b91 100644
--- a/app/src/components/FileBrowser.test.js
+++ b/app/src/components/FileBrowser.test.js
@@ -155,7 +155,9 @@ describe('FileBrowser', () => {
 
             // Find the upload button
             const buttons = screen.getAllByRole('button');
-            const uploadButton = buttons.find(btn => btn.classList.contains('green'));
+            const uploadButton = buttons.find(btn =>
+                btn.classList.contains('green') || btn.querySelector('[class*="upload"]')
+            );
 
             expect(uploadButton).not.toBeDisabled();
         });
@@ -173,7 +175,9 @@ describe('FileBrowser', () => {
 
             // Find the upload button
             const buttons = screen.getAllByRole('button');
-            const uploadButton = buttons.find(btn => btn.classList.contains('green'));
+            const uploadButton = buttons.find(btn =>
+                btn.classList.contains('green') || btn.querySelector('[class*="upload"]')
+            );
 
             expect(uploadButton).toBeDisabled();
         });
diff --git a/app/src/components/FilePreview.js b/app/src/components/FilePreview.js
index 163714df..4e28ba2d 100644
--- a/app/src/components/FilePreview.js
+++ b/app/src/components/FilePreview.js
@@ -1,14 +1,12 @@
 import React from "react";
 import _ from "lodash";
-import {Button as SButton, Dropdown, Header as SHeader, Icon, Image,} from "semantic-ui-react";
 import {TagsSelector} from "../Tags";
 import {encodeMediaPath, isSupportedArchive, useLocalStorage} from "./Common";
 import {getFile, tagFileGroup, untagFileGroup} from "../api";
 import {ArchivePreviewContent} from "./ArchivePreview";
 import {CbzViewer} from "./CbzViewer";
 import {StlViewer} from "react-stl-viewer";
-import {Button, Modal} from "./Theme";
-import {toast} from "./ui";
+import {Button, ButtonGroup, Header, Icon, IconButton, Menu, Modal, toast} from "./ui";
 import {useOneQuery} from "../hooks/customHooks";
 import {ShareButton} from "./Share";
 import {AddToPlaylistButton} from "./AddToPlaylist";
@@ -63,25 +61,31 @@ function OpenInSlicerButton({previewFile}) {
     // Browsers cannot report which slicers are installed, so remember the last one used.
     const [slicerKey, setSlicerKey] = useLocalStorage('preferredSlicer', SLICERS[0].key);
     const slicer = SLICERS.find(s => s.key === slicerKey) || SLICERS[0];
-    return <SButton.Group color='violet' size='small'>
-        <Button color='violet' as='a' href={getSlicerURL(previewFile, slicer.scheme)} icon labelPosition='left'>
-            <Icon name='cube'/>Open in {slicer.text}
+    return <ButtonGroup>
+        <Button color='violet' component='a' href={getSlicerURL(previewFile, slicer.scheme)} icon='cube' size='small'>
+            Open in {slicer.text}
         </Button>
-        <Dropdown className='button icon' floating trigger={<></>}>
-            <Dropdown.Menu>
+        <Menu position='bottom-end' withinPortal>
+            <Menu.Target>
+                <IconButton color='violet' icon='dropdown' label='Choose a different slicer' size='small'/>
+            </Menu.Target>
+            <Menu.Dropdown>
                 {SLICERS.map(s =>
-                    <Dropdown.Item key={s.key} text={`Open in ${s.text}`}
-                                   as='a' href={getSlicerURL(previewFile, s.scheme)}
-                                   onClick={(e) => {
-                                       // Navigate programmatically so keyboard activation (which may not
-                                       // follow the href) still launches the slicer.
-                                       if (e) e.preventDefault();
-                                       setSlicerKey(s.key);
-                                       window.location.assign(getSlicerURL(previewFile, s.scheme));
-                                   }}/>)}
-            </Dropdown.Menu>
-        </Dropdown>
-    </SButton.Group>
+                    <Menu.Item key={s.key}
+                               component='a' href={getSlicerURL(previewFile, s.scheme)}
+                               onClick={(e) => {
+                                   // Navigate programmatically so keyboard activation (which may not
+                                   // follow the href) still launches the slicer.
+                                   if (e) e.preventDefault();
+                                   setSlicerKey(s.key);
+                                   window.location.assign(getSlicerURL(previewFile, s.scheme));
+                               }}
+                    >
+                        Open in {s.text}
+                    </Menu.Item>)}
+            </Menu.Dropdown>
+        </Menu>
+    </ButtonGroup>
 }
 
 function getEpubViewerURL(previewFile) {
@@ -115,7 +119,7 @@ function getImagePreviewModal(previewFile) {
         <Modal.Content>
             <div className='preview-fit'>
                 <a href={url}>
-                    <Image src={url} style={{maxHeight: '100%', maxWidth: '100%', objectFit: 'contain'}}/>
+                    <img src={url} alt={name} style={{maxHeight: '100%', maxWidth: '100%', objectFit: 'contain'}}/>
                 </a>
             </div>
         </Modal.Content>
@@ -131,7 +135,7 @@ function getVideoPreviewModal(previewFile) {
             {name}
         </Modal.Header>
         <Modal.Content>
-            <SHeader as='h5'>{path['path']}</SHeader>
+            <Header as='h5'>{path['path']}</Header>
             <div className='preview-fit'>
                 <video controls
                        autoPlay={true}
@@ -416,14 +420,13 @@ export function FilePreviewProvider({children}) {
         setErrorModalOpen(false);
     }
 
-    const errorModal = <Modal closeIcon
-                              open={errorModalOpen}
+    const errorModal = <Modal open={errorModalOpen}
                               onClose={handleErrorModalClose}
     >
         <Modal.Header>Unknown File</Modal.Header>
         <Modal.Content>Cannot display preview, no such file exists: {previewQuery}</Modal.Content>
         <Modal.Actions>
-            <Button onClick={handleErrorModalClose}>Close</Button>
+            <Button role='cancel' onClick={handleErrorModalClose}>Close</Button>
         </Modal.Actions>
     </Modal>
 
@@ -500,21 +503,21 @@ export function FilePreviewProvider({children}) {
 
     function setModalContent(content, url, downloadURL, path, taggable = true, extraButtons = null) {
         // All action buttons share `size='small'` and `icon` for consistent height across viewports.
-        // Close is handled by the Modal's `closeIcon` (X in the top-right corner) — no dedicated button.
+        // Close is handled by the Modal's close button (X in the top-right corner) — no dedicated button.
         const openButton = url
-            ? <Button color='blue' as='a' href={url} size='small' icon labelPosition='left'>
-                <Icon name='external'/>Open
-            </Button>
+            ? <Button role='primary' component='a' href={url} size='small' icon='external'>Open</Button>
             : null;
         const tagsDisplay = taggable ?
             <TagsSelector selectedTagNames={previewFile['tags']} onAdd={localAddTag}
                           onRemove={localRemoveTag}/>
             : null;
         const downloadButton = downloadURL
-            ? <Button color='yellow' as='a' href={downloadURL} size='small' icon='download'/>
+            ? <IconButton color='yellow' component='a' href={downloadURL} size='small' icon='download' label='Download'/>
             : null;
         const directoryURL = path ? `/files?folders=${encodeURIComponent(pathDirectory(path))}` : null;
-        const directoryButton = path ? <Button as='a' href={directoryURL} size='small' icon='folder'/> : null;
+        const directoryButton = path
+            ? <IconButton component='a' href={directoryURL} size='small' icon='folder' label='Open containing folder'/>
+            : null;
         const pathContent = path ? <Modal.Content>
                 <pre>{path}</pre>
             </Modal.Content>
@@ -526,8 +529,7 @@ export function FilePreviewProvider({children}) {
         // Single flex toolbar — same button order at every viewport size.
         // `flex-wrap: wrap` lets the tags selector drop to a second line on narrow screens
         // while the button groups stay together and in order: [file actions] [tags] [open/close].
-        setPreviewModal(<Modal closeIcon
-                               size='fullscreen'
+        setPreviewModal(<Modal size='fullscreen'
                                open={true}
                                onClose={e => handleClose(e)}
         >
diff --git a/app/src/components/Files.js b/app/src/components/Files.js
index a1c1edbe..1b3644de 100644
--- a/app/src/components/Files.js
+++ b/app/src/components/Files.js
@@ -17,7 +17,8 @@ import {
     TagIcon,
     Toggle,
     textEllipsis,
-    useTitle
+    mimetypeColor,
+    useTitle,
 } from "./Common";
 import {
     usePages,
@@ -116,6 +117,7 @@ function EbookCard({file, sortField}) {
     return <Card media={<CardPoster file={file} to={detailUrl}/>}
                  title={<Tooltip label={title}>{header}</Tooltip>}
                  meta={meta}
+                 color={mimetypeColor(file.mimetype, file.primary_path)}
     />
 }
 
@@ -134,6 +136,7 @@ function ImageCard({file}) {
     return <Card media={<PreviewLink file={file}><CardPoster file={file}/></PreviewLink>}
                  title={<Tooltip label={title}>{header}</Tooltip>}
                  meta={meta}
+                 color={mimetypeColor(file.mimetype, file.primary_path)}
     />
 }
 
@@ -175,7 +178,8 @@ function FileCard({file}) {
             </>
         }
     </>;
-    return <Card media={<CardPoster file={file}/>} title={header} meta={meta}/>
+    return <Card media={<CardPoster file={file}/>} title={header} meta={meta}
+                 color={mimetypeColor(file.mimetype, file.primary_path)}/>
 }
 
 export function FileCards({files}) {
diff --git a/app/src/components/Flasher.js b/app/src/components/Flasher.js
index 17ba230c..fe125a69 100644
--- a/app/src/components/Flasher.js
+++ b/app/src/components/Flasher.js
@@ -1,27 +1,30 @@
-import React, {useContext, useEffect, useLayoutEffect, useRef, useState} from 'react';
+import React, {useEffect, useLayoutEffect, useRef, useState} from 'react';
 import {Route, Routes} from "react-router";
-import {Checkbox, Label, Message, Select, Button as SButton, Icon as SIcon} from "semantic-ui-react";
 import {ESPLoader, Transport} from "esptool-js";
 import {useDropzone} from "react-dropzone";
 import _ from "lodash";
 import {encodeMediaPath, humanFileSize, PageContainer, useTitle} from "./Common";
 import {
     Button,
-    darkTheme,
+    Checkbox,
     Divider,
-    Form,
+    Group,
     Header,
     Icon,
-    List,
-    Loader,
+    IconButton,
+    Label,
+    Loading,
+    Message,
     Modal,
+    Panel,
     Progress,
-    Segment,
-    Tab,
+    Select,
+    Stack,
     Table,
-    TextArea
-} from "./Theme";
-import {ThemeContext} from "../contexts/contexts";
+    Tabs,
+    Textarea,
+    TextInput,
+} from "./ui";
 import {deleteFlasherConfig, flasherSearch, getFlasherConfigs, saveFlasherConfig} from "../api";
 
 // The suffix used to find flashable ESP32 firmware in the media directory.
@@ -50,6 +53,10 @@ const KNOWN_ESP_CHIPS = [
 // colors when they render at the same width.  The first eight cover today's largest same-width group (the eight
 // 8-character ESP32-* names); the extras let a same-width group grow past eight before colors would repeat.
 // (Truly colorblind-distinct qualitative colors top out around ten, so beyond that distinctness is best-effort.)
+//
+// These are deliberately NOT theme tokens: this is a fixed categorical palette used to visually tell many ESP
+// chip families apart, the same way a chart's series colors stay fixed regardless of theme.  See the report to
+// the user for the resulting night-mode tension (non-red hues on these chips, unlike the rest of the UI).
 const CHIP_COLORS = [
     '#4477aa', '#ee6677', '#228833', '#ccbb44', '#66ccee', '#aa3377', '#bbbbbb', '#000000',
     '#ee7733', '#332288', '#999933', '#882255',
@@ -115,10 +122,10 @@ export function espImageChipId(header) {
 // bundled into the frontend build, so this works fully offline once the page has loaded.
 
 const BAUD_OPTIONS = [
-    {key: '115200', value: 115200, text: '115200 (safe)'},
-    {key: '230400', value: 230400, text: '230400'},
-    {key: '460800', value: 460800, text: '460800'},
-    {key: '921600', value: 921600, text: '921600 (fast)'},
+    {value: 115200, text: '115200 (safe)'},
+    {value: 230400, text: '230400'},
+    {value: 460800, text: '460800'},
+    {value: 921600, text: '921600 (fast)'},
 ];
 
 // Web Serial is only available in a secure context (HTTPS or localhost) on Chromium-based browsers.
@@ -218,10 +225,10 @@ export function withTimeout(promise, ms, message) {
 // How long to wait for a device to connect before giving up (esptool-js retries can otherwise stall the UI).
 const CONNECT_TIMEOUT_MS = 30_000;
 
-// A read-only log TextArea that auto-scrolls to the newest output — but only when the user is already at the
+// A read-only log Textarea that auto-scrolls to the newest output — but only when the user is already at the
 // bottom, so scrolling up to read earlier lines isn't yanked back down.  Starts at the bottom on mount (e.g. when
 // a modal opens).
-function AutoScrollLog({value, ...props}) {
+function AutoScrollLog({value, style, ...props}) {
     const containerRef = useRef(null);
     const atBottomRef = useRef(true);
 
@@ -241,13 +248,18 @@ function AutoScrollLog({value, ...props}) {
     }, [value]);
 
     return <div ref={containerRef}>
-        <TextArea readOnly value={value} onScroll={handleScroll} {...props}/>
+        <Textarea readOnly value={value} onScroll={handleScroll} styles={{input: style}} {...props}/>
     </div>;
 }
 
+// Tab keys for the firmware-source picker, in display order: saved sets first, then the media picker, then a
+// local file.
+const TAB_SAVED = 'saved';
+const TAB_WROLPI = 'wrolpi';
+const TAB_COMPUTER = 'computer';
+
 export function FlasherPage() {
     useTitle('Flasher');
-    const {t, theme} = useContext(ThemeContext);
 
     // Each entry is {name, size, address, file?: File, mediaPath?: string}.  A local file has `file`; a media
     // firmware has `mediaPath`.  Default offset 0x0 suits a single merged firmware image.
@@ -283,7 +295,7 @@ export function FlasherPage() {
     const [flashError, setFlashError] = useState('');
 
     // Which firmware-source tab is active (controlled so a file drop can switch to "Add from computer").
-    const [activeTab, setActiveTab] = useState(0);
+    const [activeTab, setActiveTab] = useState(TAB_SAVED);
 
     // Saved firmware configurations (flasher.yaml).
     const [savedConfigs, setSavedConfigs] = useState([]);
@@ -331,15 +343,14 @@ export function FlasherPage() {
         }
     };
 
-    // The "Add from computer" tab (index 2 in firmwarePanes) hosts the dropzone; a drop anywhere on the page or a
-    // click on the zone lands here.
-    const COMPUTER_TAB_INDEX = 2;
+    // The "Add from computer" tab hosts the dropzone; a drop anywhere on the page or a click on the zone lands
+    // here.
     const onDrop = React.useCallback((droppedFiles) => {
         // Only take .bin firmware; anything else dropped is ignored.
         const bins = (droppedFiles || []).filter(file => file.name.toLowerCase().endsWith(FIRMWARE_SUFFIX));
         if (bins.length > 0) {
             addFiles(bins);
-            setActiveTab(COMPUTER_TAB_INDEX);
+            setActiveTab(TAB_COMPUTER);
         }
     }, []);  // eslint-disable-line react-hooks/exhaustive-deps
     // The dropzone root wraps the whole page so firmware can be dropped anywhere.  noClick/noKeyboard because the
@@ -354,7 +365,7 @@ export function FlasherPage() {
     // While the user drags a file over the page, jump to the "Add from computer" tab so the drop target is shown.
     useEffect(() => {
         if (isDragActive) {
-            setActiveTab(COMPUTER_TAB_INDEX);
+            setActiveTab(TAB_COMPUTER);
         }
     }, [isDragActive]);
 
@@ -644,15 +655,11 @@ export function FlasherPage() {
     if (!webSerialSupported()) {
         return <PageContainer>
             <Header as='h1'>Flasher</Header>
-            <Message icon warning>
-                <SIcon name='warning sign'/>
-                <Message.Content>
-                    <Message.Header>Web Serial is not available</Message.Header>
-                    <p>Flashing requires the Web Serial API, which is only available in Chromium-based browsers
-                        (Chrome, Edge, Brave) served over a secure connection (HTTPS or <code>localhost</code>).</p>
-                    <p>Open this page in Chrome or Edge over <code>https://</code> to flash your device. Firefox
-                        and iOS are not supported.</p>
-                </Message.Content>
+            <Message kind='warning' icon='warning sign' title='Web Serial is not available'>
+                <p>Flashing requires the Web Serial API, which is only available in Chromium-based browsers
+                    (Chrome, Edge, Brave) served over a secure connection (HTTPS or <code>localhost</code>).</p>
+                <p>Open this page in Chrome or Edge over <code>https://</code> to flash your device. Firefox
+                    and iOS are not supported.</p>
             </Message>
         </PageContainer>;
     }
@@ -664,409 +671,414 @@ export function FlasherPage() {
     const totalFlashBytes = files.reduce((sum, item) => sum + (item.size || 0), 0);
     const flashEtaText = humanDuration(estimateFlashSeconds(totalFlashBytes, baudrate));
 
-    // The nested tab menu isn't inverted automatically; give it the inverted style in dark mode so it matches.
-    const tabMenu = theme === darkTheme ? {inverted: true, attached: true} : {attached: true};
-
     // A connect failure needs a download-mode reminder shown right where the user acted — both in the Connect
-    // segment and next to the "Filter files by detecting device" button so it isn't missed off-screen.
+    // panel and next to the "Filter files by detecting device" button so it isn't missed off-screen.
     const connectErrorMessage = () => (error && bootHint) &&
-        <Message error onDismiss={() => {
-            setError('');
-            setBootHint(false);
-        }} style={{marginTop: '1em'}}>
-            <Message.Header>Could not connect to the device</Message.Header>
-            <p>{error}</p>
-            <p>
-                Many ESP boards must be put into <b>download mode</b> manually before flashing. Hold the
-                {' '}<b>BOOT</b> (or <b>IO0</b>) button, briefly press <b>RESET</b> (<b>EN</b>), then release
-                BOOT and try again. Also check the USB cable is a data cable and no other tab has the port open.
-            </p>
-        </Message>;
+        <div style={{marginTop: '1em'}}>
+            <Message
+                kind='error'
+                title='Could not connect to the device'
+                onDismiss={() => {
+                    setError('');
+                    setBootHint(false);
+                }}
+            >
+                <p>{error}</p>
+                <p>
+                    Many ESP boards must be put into <b>download mode</b> manually before flashing. Hold the
+                    {' '}<b>BOOT</b> (or <b>IO0</b>) button, briefly press <b>RESET</b> (<b>EN</b>), then release
+                    BOOT and try again. Also check the USB cable is a data cable and no other tab has the port open.
+                </p>
+            </Message>
+        </div>;
 
-    // The firmware source is chosen via three tabs (see the ordered array below).
-    const computerPane = {
-            menuItem: 'Add from computer',
-            render: () => <Tab.Pane>
-                {/* Clickable drop target (files may also be dropped anywhere on the page, which routes here). */}
-                <Segment
-                    placeholder
-                    onClick={busy ? undefined : open}
+    // The firmware source is chosen via three tabs, in this order: saved sets, the media picker, then a local
+    // file.
+    const computerPaneContent = <>
+        {/* Clickable drop target (files may also be dropped anywhere on the page, which routes here). */}
+        <Panel
+            onClick={busy ? undefined : open}
+            style={{
+                cursor: busy ? 'default' : 'pointer',
+                textAlign: 'center',
+                ...(isDragActive ? {borderColor: 'var(--blue)', borderWidth: 2} : {}),
+            }}
+        >
+            <Header as='h4' icon='microchip'>
+                {isDragActive
+                    ? <>Drop <code>.bin</code> firmware to add it</>
+                    : <>Click here, or drop <code>.bin</code> firmware here</>}
+            </Header>
+        </Panel>
+        <p style={{marginTop: '1em', opacity: 0.8}}>
+            A single merged image is flashed at offset <code>0x0</code>. For multi-part firmware, add each
+            part and set its offset (e.g. bootloader <code>0x1000</code>, partitions <code>0x8000</code>,
+            app <code>0x10000</code>).
+        </p>
+    </>;
+
+    const wrolpiPaneContent = <>
+        <p style={{opacity: 0.8}}>
+            Not sure which file you need? Plug in your device and let WROLPi show only the firmware that
+            matches it.
+        </p>
+        {/* Always available so a user who swaps to a different ESP device can re-detect it. */}
+        <Button
+            icon='usb'
+            loading={connecting}
+            disabled={busy}
+            onClick={handleFilterByDevice}
+        >
+            {deviceChip ? 'Detect a different device' : 'Filter files by detecting device'}
+        </Button>
+        {/* Show a connect failure here too, so the user doesn't have to scroll to the Connect panel. */}
+        {connectErrorMessage()}
+        {deviceChip &&
+            <Message kind='info' icon='microchip'>
+                Showing firmware for <b>{deviceChip}</b>.
+                <Button role='cancel' size='xs' onClick={() => applyDeviceChip(null)}
+                        disabled={busy} style={{marginLeft: '1em'}}>
+                    Show all firmware
+                </Button>
+            </Message>}
+        <TextInput
+            style={{marginTop: '1em'}}
+            leftSection={<Icon name='search'/>}
+            placeholder='Filter firmware by path (e.g. a folder name)...'
+            value={mediaFilter}
+            disabled={busy}
+            onChange={(e) => handleMediaFilterChange(e.currentTarget.value)}
+        />
+        <div style={{marginTop: '1em', overflowX: 'auto'}}>
+            {mediaLoading
+                ? <Loading/>
+                : (mediaResults.length === 0
+                    ? <p style={{opacity: 0.7}}>
+                        No <code>.bin</code> firmware found
+                        {deviceChip ? ` for ${deviceChip}` : ' in your media directory'}
+                        {mediaFilter ? ' matching that filter.' : '.'}
+                    </p>
+                    : <Table>
+                        <Table.Header>
+                            <Table.Row>
+                                <Table.HeaderCell>File</Table.HeaderCell>
+                                <Table.HeaderCell>Path</Table.HeaderCell>
+                                <Table.HeaderCell>Size</Table.HeaderCell>
+                                <Table.HeaderCell>Chip</Table.HeaderCell>
+                                <Table.HeaderCell>Kind</Table.HeaderCell>
+                                <Table.HeaderCell style={{width: '1%'}}/>
+                            </Table.Row>
+                        </Table.Header>
+                        <Table.Body>
+                            {mediaResults.map(result => {
+                                const name = result.name || (result.primary_path || '').split('/').pop();
+                                // esp_kind is 'not_esp_image' for parts with no chip (partitions, littlefs).
+                                const kind = result.esp_kind && result.esp_kind !== 'not_esp_image'
+                                    ? result.esp_kind : null;
+                                return <Table.Row key={result.primary_path}>
+                                    <Table.Cell>{name}</Table.Cell>
+                                    <Table.Cell style={{opacity: 0.7, wordBreak: 'break-all'}}>
+                                        {result.primary_path}
+                                    </Table.Cell>
+                                    <Table.Cell>{humanFileSize(result.size)}</Table.Cell>
+                                    <Table.Cell>
+                                        {result.esp_chip
+                                            ? <span className='wrolpi-label' style={{
+                                                '--label-color': chipColor(result.esp_chip),
+                                                color: chipTextColor(chipColor(result.esp_chip)),
+                                            }}>{result.esp_chip}</span>
+                                            : <span style={{opacity: 0.5}}>—</span>}
+                                    </Table.Cell>
+                                    <Table.Cell>
+                                        {kind || <span style={{opacity: 0.5}}>—</span>}
+                                    </Table.Cell>
+                                    <Table.Cell style={{textAlign: 'center'}}>
+                                        <IconButton icon='plus' label='Add to selected firmware' role='primary'
+                                                    size='xs' disabled={busy}
+                                                    onClick={() => handleAddMediaFile(result)}/>
+                                    </Table.Cell>
+                                </Table.Row>;
+                            })}
+                        </Table.Body>
+                    </Table>)}
+        </div>
+    </>;
+
+    const savedPaneContent = <>
+        <p style={{opacity: 0.8}}>
+            Configure the firmware files and offsets, then save them as a named set to re-flash later
+            (e.g. a Meshtastic T-Deck: firmware at <code>0x0</code>, littlefs at <code>0xc90000</code>).
+        </p>
+        {savedConfigs.length > 0
+            ? <Panel style={{padding: 0}}>
+                {savedConfigs.map((configuration, index) => <div
+                    key={configuration.name}
                     style={{
-                        cursor: busy ? 'default' : 'pointer',
-                        textAlign: 'center',
-                        ...(isDragActive ? {outline: '2px dashed #2185d0', outlineOffset: '-2px'} : {}),
+                        display: 'flex',
+                        alignItems: 'center',
+                        justifyContent: 'space-between',
+                        gap: 10,
+                        padding: '10px 12px',
+                        borderBottom: index === savedConfigs.length - 1 ? undefined : '1px solid var(--border)',
                     }}
                 >
-                    <Header icon {...t}>
-                        <Icon name='microchip'/>
-                        {isDragActive
-                            ? <>Drop <code>.bin</code> firmware to add it</>
-                            : <>Click here, or drop <code>.bin</code> firmware here</>}
-                    </Header>
-                </Segment>
-                <p {...t} style={{marginTop: '1em', opacity: 0.8}}>
-                    A single merged image is flashed at offset <code>0x0</code>. For multi-part firmware, add each
-                    part and set its offset (e.g. bootloader <code>0x1000</code>, partitions <code>0x8000</code>,
-                    app <code>0x10000</code>).
-                </p>
-            </Tab.Pane>,
-    };
-    const wrolpiPane = {
-            menuItem: 'Choose from your WROLPi',
-            render: () => <Tab.Pane>
-                <p {...t} style={{opacity: 0.8}}>
-                    Not sure which file you need? Plug in your device and let WROLPi show only the firmware that
-                    matches it.
-                </p>
-                {/* Always available so a user who swaps to a different ESP device can re-detect it. */}
-                <Button
-                    icon labelPosition='left'
-                    loading={connecting}
-                    disabled={busy}
-                    onClick={handleFilterByDevice}
-                >
-                    <Icon name='usb'/>
-                    {deviceChip ? 'Detect a different device' : 'Filter files by detecting device'}
-                </Button>
-                {/* Show a connect failure here too, so the user doesn't have to scroll to the Connect segment. */}
-                {connectErrorMessage()}
-                {deviceChip &&
-                    <Message info>
-                        {/* Plain (non-inverted) icon: Message backgrounds are light, so a themed white icon
-                            vanishes. */}
-                        <SIcon name='microchip'/>
-                        Showing firmware for <b>{deviceChip}</b>.
-                        <SButton size='tiny' compact onClick={() => applyDeviceChip(null)}
-                                 disabled={busy} style={{marginLeft: '1em'}}>
-                            Show all firmware
-                        </SButton>
-                    </Message>}
-                <Form style={{marginTop: '1em'}}>
-                    <Form.Input
-                        fluid
-                        icon='search'
-                        placeholder='Filter firmware by path (e.g. a folder name)...'
-                        value={mediaFilter}
-                        disabled={busy}
-                        onChange={(e, {value}) => handleMediaFilterChange(value)}
-                    />
-                </Form>
-                <div style={{marginTop: '1em', overflowX: 'auto'}}>
-                    {mediaLoading
-                        ? <Loader active inline='centered'/>
-                        : (mediaResults.length === 0
-                            ? <p {...t} style={{opacity: 0.7}}>
-                                No <code>.bin</code> firmware found
-                                {deviceChip ? ` for ${deviceChip}` : ' in your media directory'}
-                                {mediaFilter ? ' matching that filter.' : '.'}
-                            </p>
-                            : <Table compact selectable unstackable>
-                                <Table.Header>
-                                    <Table.Row>
-                                        <Table.HeaderCell>File</Table.HeaderCell>
-                                        <Table.HeaderCell>Path</Table.HeaderCell>
-                                        <Table.HeaderCell>Size</Table.HeaderCell>
-                                        <Table.HeaderCell>Chip</Table.HeaderCell>
-                                        <Table.HeaderCell>Kind</Table.HeaderCell>
-                                        <Table.HeaderCell width={1}/>
-                                    </Table.Row>
-                                </Table.Header>
-                                <Table.Body>
-                                    {mediaResults.map(result => {
-                                        const name = result.name || (result.primary_path || '').split('/').pop();
-                                        // esp_kind is 'not_esp_image' for parts with no chip (partitions, littlefs).
-                                        const kind = result.esp_kind && result.esp_kind !== 'not_esp_image'
-                                            ? result.esp_kind : null;
-                                        return <Table.Row key={result.primary_path}>
-                                            <Table.Cell>{name}</Table.Cell>
-                                            <Table.Cell {...t} style={{opacity: 0.7, wordBreak: 'break-all'}}>
-                                                {result.primary_path}
-                                            </Table.Cell>
-                                            <Table.Cell>{humanFileSize(result.size)}</Table.Cell>
-                                            <Table.Cell>
-                                                {result.esp_chip
-                                                    ? <Label size='tiny' style={{
-                                                        backgroundColor: chipColor(result.esp_chip),
-                                                        color: chipTextColor(chipColor(result.esp_chip)),
-                                                        borderColor: 'transparent',
-                                                    }}>{result.esp_chip}</Label>
-                                                    : <span style={{opacity: 0.5}}>—</span>}
-                                            </Table.Cell>
-                                            <Table.Cell>
-                                                {kind || <span style={{opacity: 0.5}}>—</span>}
-                                            </Table.Cell>
-                                            <Table.Cell textAlign='center'>
-                                                <Button icon='plus' size='mini' primary disabled={busy}
-                                                        title='Add to selected firmware'
-                                                        onClick={() => handleAddMediaFile(result)}/>
-                                            </Table.Cell>
-                                        </Table.Row>;
-                                    })}
-                                </Table.Body>
-                            </Table>)}
-                </div>
-            </Tab.Pane>,
-    };
-    const savedPane = {
-            menuItem: 'Saved Firmwares',
-            render: () => <Tab.Pane>
-                <p {...t} style={{opacity: 0.8}}>
-                    Configure the firmware files and offsets, then save them as a named set to re-flash later
-                    (e.g. a Meshtastic T-Deck: firmware at <code>0x0</code>, littlefs at <code>0xc90000</code>).
-                </p>
-                {savedConfigs.length > 0
-                    ? <List divided relaxed selection>
-                        {savedConfigs.map(configuration => <List.Item key={configuration.name}>
-                            <List.Content floated='right'>
-                                <Button icon='trash' size='mini' color='red' disabled={busy}
-                                        onClick={() => handleDeleteConfig(configuration.name)}/>
-                            </List.Content>
-                            <List.Icon name='save' verticalAlign='middle'/>
-                            <List.Content onClick={busy ? undefined : () => handleLoadConfig(configuration)}
-                                          style={busy ? {} : {cursor: 'pointer'}}>
-                                <List.Header>{configuration.name}</List.Header>
-                                <List.Description {...t}>
-                                    {(configuration.files || []).length} file(s)
-                                    {configuration.erase_all ? ' — erases flash' : ''}
-                                </List.Description>
-                            </List.Content>
-                        </List.Item>)}
-                    </List>
-                    : <p {...t} style={{opacity: 0.7}}>No saved configurations yet.</p>}
-            </Tab.Pane>,
-    };
-    // Tab order: saved sets first, then the media picker, then a local file.
-    const firmwarePanes = [savedPane, wrolpiPane, computerPane];
+                    <div
+                        onClick={busy ? undefined : () => handleLoadConfig(configuration)}
+                        style={{
+                            display: 'flex', alignItems: 'center', gap: 10, flex: 1,
+                            cursor: busy ? 'default' : 'pointer',
+                        }}
+                    >
+                        <Icon name='save'/>
+                        <div>
+                            <div style={{fontWeight: 600}}>{configuration.name}</div>
+                            <div style={{fontSize: 12, opacity: 0.8}}>
+                                {(configuration.files || []).length} file(s)
+                                {configuration.erase_all ? ' — erases flash' : ''}
+                            </div>
+                        </div>
+                    </div>
+                    <IconButton icon='trash' label={`Delete ${configuration.name}`} role='danger' size='xs'
+                                disabled={busy}
+                                onClick={() => handleDeleteConfig(configuration.name)}/>
+                </div>)}
+            </Panel>
+            : <p style={{opacity: 0.7}}>No saved configurations yet.</p>}
+    </>;
 
     return <div {...getRootProps()}>
         {/* The dropzone root wraps the whole page: firmware .bin files can be dropped anywhere and are routed to
             the "Add from computer" tab.  noClick is set, so this wrapper never opens the file dialog itself. */}
         <input {...getInputProps()}/>
         <PageContainer>
-        <Header as='h1'>Flasher</Header>
-        <p {...t}>
-            Flash firmware onto an ESP32/ESP8266 device directly from your browser over USB. Choose one or more
-            firmware <code>.bin</code> files &mdash; from your computer or from your WROLPi's media directory &mdash;
-            connect your device, then flash. The flash happens entirely in your browser and is written straight to
-            the device over USB.
-        </p>
+            <Header as='h1'>Flasher</Header>
+            <p>
+                Flash firmware onto an ESP32/ESP8266 device directly from your browser over USB. Choose one or
+                more firmware <code>.bin</code> files &mdash; from your computer or from your WROLPi's media
+                directory &mdash; connect your device, then flash. The flash happens entirely in your browser and
+                is written straight to the device over USB.
+            </p>
 
-        {/* Connection errors render inside the Connect segment (below), where the user just clicked.  Other
-            errors show here at the top. */}
-        {error && !bootHint && <Message error onDismiss={() => setError('')}>
-            <Message.Header>Error</Message.Header>
-            <p>{error}</p>
-        </Message>}
+            {/* Connection errors render inside the Connect panel (below), where the user just clicked.  Other
+                errors show here at the top. */}
+            {error && !bootHint && <Message kind='error' title='Error' onDismiss={() => setError('')}>
+                <p>{error}</p>
+            </Message>}
 
-        <Segment>
-            <Header as='h3'>1. Firmware files</Header>
-            <Tab
-                menu={tabMenu}
-                panes={firmwarePanes}
-                activeIndex={activeTab}
-                onTabChange={(e, {activeIndex}) => setActiveTab(activeIndex)}
-            />
+            <Panel>
+                <Header as='h3'>1. Firmware files</Header>
+                <Tabs value={activeTab} onChange={setActiveTab} keepMounted={false}>
+                    <Tabs.List>
+                        <Tabs.Tab value={TAB_SAVED}>Saved Firmwares</Tabs.Tab>
+                        <Tabs.Tab value={TAB_WROLPI}>Choose from your WROLPi</Tabs.Tab>
+                        <Tabs.Tab value={TAB_COMPUTER}>Add from computer</Tabs.Tab>
+                    </Tabs.List>
+                    <Tabs.Panel value={TAB_SAVED} pt='md'>{savedPaneContent}</Tabs.Panel>
+                    <Tabs.Panel value={TAB_WROLPI} pt='md'>{wrolpiPaneContent}</Tabs.Panel>
+                    <Tabs.Panel value={TAB_COMPUTER} pt='md'>{computerPaneContent}</Tabs.Panel>
+                </Tabs>
 
-            {/* The selected firmware is shown below the source tabs so it stays visible regardless of which tab
-                (computer / WROLPi / saved) the user is on. */}
-            {files.length > 0 && <>
-                <Divider/>
-                <Header as='h4'>Selected firmware</Header>
-                <Table compact unstackable>
-                    <Table.Header>
-                        <Table.Row>
-                            <Table.HeaderCell>File</Table.HeaderCell>
-                            <Table.HeaderCell width={4}>Flash offset</Table.HeaderCell>
-                            <Table.HeaderCell width={1}/>
-                        </Table.Row>
-                    </Table.Header>
-                    <Table.Body>
-                        {files.map((item, index) => {
-                            // Flag (but never block) a file whose image targets a different chip than the device.
-                            const fileChipId = fileChipIds[index];
-                            const chipMismatch = deviceChipId !== null && fileChipId != null
-                                && fileChipId !== deviceChipId;
-                            return <Table.Row key={`${item.name}-${index}`} warning={chipMismatch}>
-                            <Table.Cell>
-                                <Icon name={item.mediaPath ? 'database' : 'file'}/>
-                                {item.name} <span style={{opacity: 0.6}}>({humanFileSize(item.size)})</span>
-                                {chipMismatch &&
-                                    <Label color='red' size='tiny' style={{marginLeft: '0.5em'}}>
-                                        <SIcon name='warning sign'/>
-                                        Built for {chipIdName(fileChipId)}, not {chipIdName(deviceChipId)}
-                                    </Label>}
-                            </Table.Cell>
-                            <Table.Cell>
-                                <Form.Input
-                                    fluid
-                                    size='small'
-                                    placeholder='0x10000'
-                                    value={item.address}
-                                    disabled={busy}
-                                    error={!isValidHexOffset(item.address)}
-                                    onChange={(e, {value}) => handleAddressChange(index, value)}
-                                />
-                            </Table.Cell>
-                            <Table.Cell textAlign='center'>
-                                <Button icon='trash' size='mini' color='red' disabled={busy}
-                                        onClick={() => handleRemoveFile(index)}/>
-                            </Table.Cell>
-                        </Table.Row>;
-                        })}
-                    </Table.Body>
-                </Table>
-                {/* Save lives here (not in the Saved Firmwares tab) so the current selection can be saved from
-                    any source tab. */}
-                <Button icon labelPosition='left' disabled={busy || saveableFiles.length === 0}
-                        onClick={() => setSaveModalOpen(true)}>
-                    <Icon name='save'/>
-                    Save current firmware
-                </Button>
-            </>}
-        </Segment>
+                {/* The selected firmware is shown below the source tabs so it stays visible regardless of which
+                    tab (computer / WROLPi / saved) the user is on. */}
+                {files.length > 0 && <>
+                    <Divider/>
+                    <Header as='h4'>Selected firmware</Header>
+                    <Table>
+                        <Table.Header>
+                            <Table.Row>
+                                <Table.HeaderCell>File</Table.HeaderCell>
+                                <Table.HeaderCell style={{width: '30%'}}>Flash offset</Table.HeaderCell>
+                                <Table.HeaderCell style={{width: '1%'}}/>
+                            </Table.Row>
+                        </Table.Header>
+                        <Table.Body>
+                            {files.map((item, index) => {
+                                // Flag (but never block) a file whose image targets a different chip than the
+                                // device.
+                                const fileChipId = fileChipIds[index];
+                                const chipMismatch = deviceChipId !== null && fileChipId != null
+                                    && fileChipId !== deviceChipId;
+                                return <Table.Row key={`${item.name}-${index}`}>
+                                    <Table.Cell>
+                                        <Icon name={item.mediaPath ? 'disk' : 'file'}/>
+                                        {' '}{item.name} <span style={{opacity: 0.6}}>
+                                            ({humanFileSize(item.size)})
+                                        </span>
+                                        {chipMismatch &&
+                                            <span style={{marginLeft: '0.5em'}}>
+                                                <Label color='red' icon='warning sign'>
+                                                    Built for {chipIdName(fileChipId)}, not{' '}
+                                                    {chipIdName(deviceChipId)}
+                                                </Label>
+                                            </span>}
+                                    </Table.Cell>
+                                    <Table.Cell>
+                                        <TextInput
+                                            size='xs'
+                                            placeholder='0x10000'
+                                            value={item.address}
+                                            disabled={busy}
+                                            error={!isValidHexOffset(item.address)}
+                                            onChange={(e) => handleAddressChange(index, e.currentTarget.value)}
+                                        />
+                                    </Table.Cell>
+                                    <Table.Cell style={{textAlign: 'center'}}>
+                                        <IconButton icon='trash' label={`Remove ${item.name}`} role='danger'
+                                                    size='xs' disabled={busy}
+                                                    onClick={() => handleRemoveFile(index)}/>
+                                    </Table.Cell>
+                                </Table.Row>;
+                            })}
+                        </Table.Body>
+                    </Table>
+                    {/* Save lives here (not in the Saved Firmwares tab) so the current selection can be saved
+                        from any source tab. */}
+                    <Button icon='save' role='save' disabled={busy || saveableFiles.length === 0}
+                            onClick={() => setSaveModalOpen(true)}>
+                        Save current firmware
+                    </Button>
+                </>}
+            </Panel>
 
-        <Modal open={saveModalOpen} onClose={() => setSaveModalOpen(false)} size='tiny'>
-            <Modal.Header>Save firmware configuration</Modal.Header>
-            <Modal.Content>
-                <Form onSubmit={handleSaveConfig}>
-                    <Form.Input
+            <Modal open={saveModalOpen} onClose={() => setSaveModalOpen(false)} size='sm'>
+                <Modal.Header>Save firmware configuration</Modal.Header>
+                <Modal.Content>
+                    <TextInput
                         autoFocus
                         label='Name'
                         placeholder='e.g. T-Deck Meshtastic UI'
                         value={saveName}
-                        onChange={(e, {value}) => setSaveName(value)}
+                        onChange={(e) => setSaveName(e.currentTarget.value)}
                     />
-                    <p {...t} style={{opacity: 0.8}}>
+                    <p style={{opacity: 0.8, marginTop: '0.75em'}}>
                         Saving {saveableFiles.length} firmware file(s) from your WROLPi. An existing configuration
                         with the same name will be replaced.
                     </p>
-                </Form>
-            </Modal.Content>
-            <Modal.Actions>
-                <SButton onClick={() => setSaveModalOpen(false)}>Cancel</SButton>
-                <Button primary disabled={!saveName.trim()} onClick={handleSaveConfig}>Save</Button>
-            </Modal.Actions>
-        </Modal>
+                </Modal.Content>
+                <Modal.Actions>
+                    <Button role='cancel' onClick={() => setSaveModalOpen(false)}>Cancel</Button>
+                    <Button role='save' disabled={!saveName.trim()} onClick={handleSaveConfig}>Save</Button>
+                </Modal.Actions>
+            </Modal>
 
-        <Segment>
-            <Header as='h3'>2. Connect</Header>
-            <Form>
-                <Form.Field>
-                    <label>Baud rate</label>
-                    <Select
-                        options={BAUD_OPTIONS}
-                        value={baudrate}
-                        disabled={connected || busy}
-                        onChange={(e, {value}) => setBaudrate(value)}
-                    />
-                </Form.Field>
-                {connected &&
-                    <Message positive>
-                        <SIcon name='usb'/> Connected to <b>{chip}</b>
-                    </Message>}
-                {connected
-                    ? <Button color='grey' disabled={busy} onClick={disconnect}>Disconnect</Button>
-                    : <Button primary loading={connecting} disabled={busy} onClick={handleConnect}>
-                        Connect Device
-                    </Button>}
-                <Button icon labelPosition='left' disabled={!log} onClick={() => setLogOpen(true)}>
-                    <Icon name='terminal'/> Logs
-                </Button>
-            </Form>
-            {/* Rendered outside <Form> so Semantic's ".ui.form .error.message { display:none }" rule doesn't
-                hide it, and here (not at the top) so it is visible right where the user clicked Connect. */}
-            {connectErrorMessage()}
-        </Segment>
+            <Panel>
+                <Header as='h3'>2. Connect</Header>
+                <Stack gap={12} style={{maxWidth: 320}}>
+                    <div>
+                        <div style={{marginBottom: 4, fontSize: 13, fontWeight: 500}}>Baud rate</div>
+                        <Select
+                            data={BAUD_OPTIONS.map(o => ({value: String(o.value), label: o.text}))}
+                            value={String(baudrate)}
+                            disabled={connected || busy}
+                            allowDeselect={false}
+                            onChange={(value) => value && setBaudrate(Number(value))}
+                        />
+                    </div>
+                    {connected &&
+                        <Message kind='success' icon='usb'>Connected to <b>{chip}</b></Message>}
+                    <Group>
+                        {connected
+                            ? <Button role='cancel' disabled={busy} onClick={disconnect}>Disconnect</Button>
+                            : <Button role='primary' loading={connecting} disabled={busy} onClick={handleConnect}>
+                                Connect Device
+                            </Button>}
+                        <Button icon='terminal' disabled={!log} onClick={() => setLogOpen(true)}>
+                            Logs
+                        </Button>
+                    </Group>
+                </Stack>
+                {/* Rendered outside the fields above, and here (not at the top) so it is visible right where
+                    the user clicked Connect. */}
+                {connectErrorMessage()}
+            </Panel>
 
-        <Segment>
-            <Header as='h3'>3. Flash</Header>
-            <Form>
-                <Form.Field>
+            <Panel danger>
+                <Header as='h3'>3. Flash</Header>
+                <Stack gap={12}>
                     <Checkbox
                         label='Erase all flash before writing'
                         checked={eraseAll}
                         disabled={busy}
-                        onChange={(e, {checked}) => setEraseAll(checked)}
+                        onChange={(e) => setEraseAll(e.currentTarget.checked)}
                     />
-                </Form.Field>
-                <Button
-                    color='red'
-                    loading={flashing}
-                    disabled={!connected || flashing || files.length === 0 || !offsetsValid}
-                    onClick={handleFlash}
-                >
-                    <Icon name='lightning'/> Flash Device
-                </Button>
-                {offsetsValid && flashEtaText &&
-                    <span {...t} style={{marginLeft: '1em', opacity: 0.8}}>
-                        Estimated time: ~{flashEtaText} at {baudrate.toLocaleString()} baud
-                    </span>}
-                {files.length > 0 && !offsetsValid &&
-                    <p {...t} style={{marginTop: '0.5em', opacity: 0.8}}>
-                        Every firmware file needs a valid hex flash offset (e.g. <code>0x0</code> or{' '}
-                        <code>0x10000</code>).
-                    </p>}
-            </Form>
-        </Segment>
+                    <div>
+                        <Button
+                            role='danger'
+                            icon='lightning'
+                            loading={flashing}
+                            disabled={!connected || flashing || files.length === 0 || !offsetsValid}
+                            onClick={handleFlash}
+                        >
+                            Flash Device
+                        </Button>
+                        {offsetsValid && flashEtaText &&
+                            <span style={{marginLeft: '1em', opacity: 0.8}}>
+                                Estimated time: ~{flashEtaText} at {baudrate.toLocaleString()} baud
+                            </span>}
+                    </div>
+                    {files.length > 0 && !offsetsValid &&
+                        <p style={{opacity: 0.8}}>
+                            Every firmware file needs a valid hex flash offset (e.g. <code>0x0</code> or{' '}
+                            <code>0x10000</code>).
+                        </p>}
+                </Stack>
+            </Panel>
 
-        <Modal
-            open={flashOpen}
-            onClose={() => !flashing && setFlashOpen(false)}
-            closeOnDimmerClick={!flashing}
-            size='fullscreen'
-        >
-            <Modal.Header>{flashing ? 'Flashing device…' : (flashError ? 'Flash failed' : 'Flash complete')}</Modal.Header>
-            <Modal.Content scrolling>
-                {progress !== null &&
-                    <Progress percent={progress.percent} progress indicating={flashing}
-                              error={!!flashError} autoSuccess={!flashError}>
-                        {flashing ? `Writing file ${progress.fileIndex + 1} of ${files.length}`
-                            : (flashError ? 'Failed' : 'Done')}
-                    </Progress>}
-                {flashing && flashEtaText &&
-                    <p {...t} style={{opacity: 0.8}}>
-                        Estimated total time: ~{flashEtaText} at {baudrate.toLocaleString()} baud. Keep this tab
-                        open and do not unplug the device.
-                    </p>}
-                {/* Surface a failure right here — otherwise a failed flash looks identical to a frozen one. */}
-                {flashError &&
-                    <Message error>
-                        <SIcon name='warning circle'/>
-                        <Message.Content>
-                            <Message.Header>Flashing failed</Message.Header>
+            <Modal
+                open={flashOpen}
+                onClose={() => !flashing && setFlashOpen(false)}
+                closeOnClickOutside={!flashing}
+                closeOnEscape={!flashing}
+                size='fullscreen'
+            >
+                <Modal.Header>
+                    {flashing ? 'Flashing device…' : (flashError ? 'Flash failed' : 'Flash complete')}
+                </Modal.Header>
+                <Modal.Content>
+                    {progress !== null &&
+                        <Progress
+                            percent={progress.percent}
+                            color={flashError ? 'red' : (flashing ? 'blue' : 'green')}
+                            label={flashing ? `Writing file ${progress.fileIndex + 1} of ${files.length}`
+                                : (flashError ? 'Failed' : 'Done')}
+                        />}
+                    {flashing && flashEtaText &&
+                        <p style={{opacity: 0.8}}>
+                            Estimated total time: ~{flashEtaText} at {baudrate.toLocaleString()} baud. Keep this
+                            tab open and do not unplug the device.
+                        </p>}
+                    {/* Surface a failure right here — otherwise a failed flash looks identical to a frozen
+                        one. */}
+                    {flashError &&
+                        <Message kind='error' icon='warning circle' title='Flashing failed'>
                             <p>{flashError}</p>
-                        </Message.Content>
-                    </Message>}
-                {!flashing && !flashError && progress !== null &&
-                    <Message success>
-                        <SIcon name='check circle'/>
-                        <Message.Content>
-                            <Message.Header>Flashing complete</Message.Header>
+                        </Message>}
+                    {!flashing && !flashError && progress !== null &&
+                        <Message kind='success' icon='check circle' title='Flashing complete'>
                             <p>Unplug the device and power it back on to run the new firmware.</p>
-                        </Message.Content>
-                    </Message>}
-                <AutoScrollLog
-                    value={log || 'Starting…'}
-                    style={{fontFamily: 'monospace', width: '100%', minHeight: '60vh', whiteSpace: 'pre'}}
-                />
-            </Modal.Content>
-            <Modal.Actions>
-                <Button onClick={() => setFlashOpen(false)} disabled={flashing}>Close</Button>
-            </Modal.Actions>
-        </Modal>
+                        </Message>}
+                    <AutoScrollLog
+                        value={log || 'Starting…'}
+                        style={{fontFamily: 'var(--font-mono)', width: '100%', minHeight: '60vh', whiteSpace: 'pre'}}
+                    />
+                </Modal.Content>
+                <Modal.Actions>
+                    <Button role='cancel' onClick={() => setFlashOpen(false)} disabled={flashing}>Close</Button>
+                </Modal.Actions>
+            </Modal>
 
-        <Modal open={logOpen} onClose={() => setLogOpen(false)} size='fullscreen'>
-            <Modal.Header>Flasher Log</Modal.Header>
-            <Modal.Content scrolling>
-                <AutoScrollLog
-                    value={log || 'No activity yet.'}
-                    style={{fontFamily: 'monospace', width: '100%', minHeight: '70vh', whiteSpace: 'pre'}}
-                />
-            </Modal.Content>
-            <Modal.Actions>
-                <Button onClick={() => setLogOpen(false)}>Close</Button>
-            </Modal.Actions>
-        </Modal>
+            <Modal open={logOpen} onClose={() => setLogOpen(false)} size='fullscreen'>
+                <Modal.Header>Flasher Log</Modal.Header>
+                <Modal.Content>
+                    <AutoScrollLog
+                        value={log || 'No activity yet.'}
+                        style={{fontFamily: 'var(--font-mono)', width: '100%', minHeight: '70vh', whiteSpace: 'pre'}}
+                    />
+                </Modal.Content>
+                <Modal.Actions>
+                    <Button role='cancel' onClick={() => setLogOpen(false)}>Close</Button>
+                </Modal.Actions>
+            </Modal>
         </PageContainer>
     </div>;
 }
diff --git a/app/src/components/Flasher.test.js b/app/src/components/Flasher.test.js
index 2156a57d..34ca2301 100644
--- a/app/src/components/Flasher.test.js
+++ b/app/src/components/Flasher.test.js
@@ -1,5 +1,5 @@
 import React from 'react';
-import {fireEvent, render, screen, waitFor} from '@testing-library/react';
+import {fireEvent, render, screen, waitFor} from '../test-utils';
 
 // esptool-js ships untranspiled ESM which Jest will not transform; mock it so importing Flasher.js is safe.
 // Real classes (not jest.fn mock impls) so `new ESPLoader()` reliably yields an instance with main()/after().
diff --git a/app/src/components/Nav.js b/app/src/components/Nav.js
index c4077de0..09ad2da0 100644
--- a/app/src/components/Nav.js
+++ b/app/src/components/Nav.js
@@ -1,7 +1,8 @@
 import React from "react";
 import {Link, NavLink} from "react-router";
-import {Dropdown, Icon as SIcon, Menu} from "semantic-ui-react";
-import {Media, SettingsContext, StatusContext, ThemeContext} from "../contexts/contexts";
+import {IconMenu2, IconPlugOff, IconTemperature, IconTemperaturePlus} from "@tabler/icons-react";
+import {Icon, IconButton, Menu, Tooltip} from "./ui";
+import {Media, SettingsContext, StatusContext} from "../contexts/contexts";
 import {DarkModeToggle, HotspotStatusIcon, useLocalStorage} from "./Common";
 import {ShareButton} from "./Share";
 import {
@@ -16,7 +17,6 @@ import {
 } from "../hooks/customHooks";
 import {useReorganizationStatus} from "../contexts/FileWorkerStatusContext";
 import {SearchIconButton} from "./Search";
-import {Icon, Popup} from "./Theme";
 import {HELP_VIEWER_URI, NAME, semanticUIColorMap} from "./Vars";
 import {useOverflowNav} from "../hooks/useOverflowNav";
 import _ from "lodash";
@@ -44,6 +44,10 @@ function updateFavicon(colorName) {
     if (themeColorMeta) themeColorMeta.content = hexColor;
 }
 
+// A theme token name, or null to inherit the surrounding text/icon color (never
+// literally "var(--null)").
+const colorVar = (color) => color ? `var(--${color})` : undefined;
+
 const help = {to: HELP_VIEWER_URI, text: 'Help', key: 'help', target: '_blank'};
 const admin = {to: '/admin', text: 'Admin', key: 'admin'};
 const rightLinks = [help, admin];
@@ -61,30 +65,68 @@ const allLinks = [
     {to: '/more/statistics', text: 'Statistics', key: 'statistics', end: true},
 ];
 
-function DropdownLinks({link}) {
-    return <Dropdown item text={link.text} direction='left'>
-        <Dropdown.Menu>
-            {link.links.map(l => <MenuLink key={l.to} link={l}/>)}
-        </Dropdown.Menu>
-    </Dropdown>
-}
-
 function MenuLink({link}) {
-    // Wrapper around NavLink to handle Navlink/Dropdown change.
+    // A top-level tab rendered directly in the bar (not inside a dropdown).
     if (link.links) {
         return <DropdownLinks link={link}/>
-    } else {
-        const end = link.end ? {end: true} : {end: undefined};
-        const target = link.target ? {target: link.target} : {};
-        return <NavLink
-            className='item'
-            to={link.to}
-            {...end}
-            {...target}
-        >
-            {link.text}
-        </NavLink>
     }
+    const end = link.end ? {end: true} : {};
+    const target = link.target ? {target: link.target, rel: 'noopener noreferrer'} : {};
+    return <NavLink
+        className='wrolpi-navbar-link'
+        to={link.to}
+        {...end}
+        {...target}
+    >
+        {link.text}
+    </NavLink>
+}
+
+function DropdownMenuItem({link}) {
+    // An item inside a Menu.Dropdown: the mobile hamburger menu, or the desktop
+    // "More" overflow menu.
+    if (link.links) {
+        // Mantine's Menu does not nest submenus without extra plumbing; a labelled,
+        // indented group stands in for Semantic's nested Dropdown.  No current data
+        // uses this path (no allLinks entry has its own `links`).
+        return <React.Fragment>
+            <Menu.Label>{link.text}</Menu.Label>
+            {link.links.map(l => <DropdownMenuItem key={l.key} link={l}/>)}
+        </React.Fragment>
+    }
+    const end = link.end ? {end: true} : {};
+    const target = link.target ? {target: link.target, rel: 'noopener noreferrer'} : {};
+    return <Menu.Item component={NavLink} to={link.to} {...end} {...target}>
+        {link.text}
+    </Menu.Item>
+}
+
+function DropdownLinks({link}) {
+    // A labelled dropdown trigger: the desktop "More" overflow, or any nested
+    // link group handed to MenuLink.
+    return <Menu position='bottom-end' withinPortal>
+        <Menu.Target>
+            <button type='button' className='wrolpi-navbar-link wrolpi-navbar-link-button'>
+                {link.text}
+                <Icon name='dropdown' size='small' style={{marginLeft: '0.35em'}}/>
+            </button>
+        </Menu.Target>
+        <Menu.Dropdown>
+            {link.links.map(l => <DropdownMenuItem key={l.key} link={l}/>)}
+        </Menu.Dropdown>
+    </Menu>
+}
+
+function MobileMenu({links}) {
+    // The mobile hamburger menu: an icon-only trigger holding every link.
+    return <Menu position='bottom-end' withinPortal>
+        <Menu.Target>
+            <IconButton icon={IconMenu2} label='Menu' variant='subtle'/>
+        </Menu.Target>
+        <Menu.Dropdown>
+            {links.map(link => <DropdownMenuItem key={link.key} link={link}/>)}
+        </Menu.Dropdown>
+    </Menu>
 }
 
 function NavIconWrapper({children}) {
@@ -123,10 +165,9 @@ export function NavBar() {
     const navColor = useNavColorSetting();
     const wrolpiIcon = <img src='/icon.svg' height='32px' width='32px' alt='WROLPi Home Icon'/>;
     const name = <i>{NAME || wrolpiIcon}</i>;
-    const topNavText = wrolModeEnabled ? <>{name}&nbsp; <SIcon name='lock'/></> : name;
-    const {i} = React.useContext(ThemeContext);
+    const topNavText = wrolModeEnabled ? <>{name}&nbsp; <Icon name='lock'/></> : name;
 
-    const homeLink = <NavLink className='item' to='/' style={{paddingTop: 0, paddingBottom: 0}}>
+    const homeLink = <NavLink className='wrolpi-navbar-link' to='/' style={{paddingTop: 0, paddingBottom: 0}}>
         {topNavText}
     </NavLink>;
 
@@ -143,9 +184,10 @@ export function NavBar() {
         // System load is high, display a warning icon.
         const color = highLoad ? highWarningColor : lowWarningColor;
         const icon = <Link to='/admin/status'>
-            <Icon name='tachometer alternate' size='large' color={color}/>
+            <Icon name='tachometer alternate' size='large' style={{color: colorVar(color)}}
+                  label='System load warning'/>
         </Link>;
-        systemLoadIcon = <Popup content={`Load: ${minute_1}`} trigger={icon}/>
+        systemLoadIcon = <Tooltip label={`Load: ${minute_1}`}>{icon}</Tooltip>
     }
 
     // RAM consumption.
@@ -153,10 +195,16 @@ export function NavBar() {
     let memoryIcon;
     if (memoryPercent > 80) {
         const color = memoryPercent > 90 ? highWarningColor : lowWarningColor;
-        const icon = <Link to='/admin/status' color={color}>
-            <Icon name='microchip' size='large'/>
+        {/*
+          The colour goes on the Icon, as it does for every other indicator.  It used to
+          be passed to `Link`, which ignores it, so the memory warning never actually
+          changed colour -- 81% and 95% looked identical.
+        */}
+        const icon = <Link to='/admin/status'>
+            <Icon name='microchip' size='large' label='Memory usage warning'
+                  style={{color: colorVar(color)}}/>
         </Link>;
-        memoryIcon = <Popup content={`System Memory: ${memoryPercent.toFixed()}%`} trigger={icon}/>
+        memoryIcon = <Tooltip label={`System Memory: ${memoryPercent.toFixed()}%`}>{icon}</Tooltip>
     }
 
     // Any disk is busy and processes are waiting.
@@ -166,9 +214,9 @@ export function NavBar() {
         // Processes are waiting on disk, display a warning icon.
         const color = percentIOWait > 75 ? highWarningColor : lowWarningColor;
         const icon = <Link to='/admin/status'>
-            <Icon name='disk' size='large' color={color}/>
+            <Icon name='disk' size='large' style={{color: colorVar(color)}} label='Disk I/O wait warning'/>
         </Link>;
-        diskWaitIcon = <Popup content={`Processes waiting on disk: ${percentIOWait.toFixed()}%`} trigger={icon}/>
+        diskWaitIcon = <Tooltip label={`Processes waiting on disk: ${percentIOWait.toFixed()}%`}>{icon}</Tooltip>
     }
 
     // CPU temperature.
@@ -177,10 +225,11 @@ export function NavBar() {
     if (temperature && temperature >= highTemperature) {
         // CPU temperature is high, display a warning icon.
         const color = temperature >= criticalTemperature ? highWarningColor : lowWarningColor;
-        const name = temperature >= criticalTemperature ? 'thermometer' : 'thermometer half';
-        const icon = <Icon data-testid='cpuTemperatureIcon' name={name} size='large' color={color}/>
+        const temperatureComponent = temperature >= criticalTemperature ? IconTemperaturePlus : IconTemperature;
+        const icon = <Icon data-testid='cpuTemperatureIcon' component={temperatureComponent} size='large'
+                            style={{color: colorVar(color)}} label='CPU temperature warning'/>
         const link = <Link to='/admin/status'>{icon}</Link>;
-        temperatureIcon = <Popup content={`CPU: ${temperature.toFixed()}°C`} trigger={link}/>;
+        temperatureIcon = <Tooltip label={`CPU: ${temperature.toFixed()}°C`}>{link}</Tooltip>;
     }
 
     // Hard-drive temperature.  An overheating drive risks data loss.
@@ -193,9 +242,10 @@ export function NavBar() {
     let driveTemperatureIcon;
     if (driveTemperature && driveTemperature >= driveHighTemperature) {
         const color = driveTemperature >= driveCriticalTemperature ? highWarningColor : lowWarningColor;
-        const icon = <Icon data-testid='driveTemperatureIcon' name='hdd' size='large' color={color}/>
+        const icon = <Icon data-testid='driveTemperatureIcon' name='hdd' size='large'
+                            style={{color: colorVar(color)}} label='Drive temperature warning'/>
         const link = <Link to='/admin/controller'>{icon}</Link>;
-        driveTemperatureIcon = <Popup content={`${hotDrive}: ${driveTemperature.toFixed()}°C`} trigger={link}/>;
+        driveTemperatureIcon = <Tooltip label={`${hotDrive}: ${driveTemperature.toFixed()}°C`}>{link}</Tooltip>;
     }
 
     // A drive's SMART health is degraded.  FAIL is an imminent failure (back
@@ -206,31 +256,36 @@ export function NavBar() {
     const {failingDevices, failing: driveFailing, warningDevices, warning: driveWarning} = useDriveHealth();
     let driveHealthIcon;
     if (driveFailing) {
-        const icon = <Icon data-testid='driveHealthIcon' name='warning sign' size='large' color={highWarningColor}/>;
+        const icon = <Icon data-testid='driveHealthIcon' name='warning sign' size='large'
+                            style={{color: colorVar(highWarningColor)}} label='Drive health failing'/>;
         const link = <Link to='/admin/controller'>{icon}</Link>;
         const message = failingDevices.length === 1
             ? `Drive ${failingDevices[0]} is failing its SMART health check! Back up your data.`
             : `Drives failing SMART health check: ${failingDevices.join(', ')}. Back up your data.`;
-        driveHealthIcon = <Popup content={message} trigger={link}/>;
+        driveHealthIcon = <Tooltip label={message}>{link}</Tooltip>;
     } else if (driveWarning) {
-        const icon = <Icon data-testid='driveHealthIcon' name='warning sign' size='large' color={lowWarningColor}/>;
+        const icon = <Icon data-testid='driveHealthIcon' name='warning sign' size='large'
+                            style={{color: colorVar(lowWarningColor)}} label='Drive health warning'/>;
         const link = <Link to='/admin/controller'>{icon}</Link>;
         const message = warningDevices.length === 1
             ? `Drive ${warningDevices[0]} has unreadable or pending sectors — check its SMART health.`
             : `Drives with unreadable or pending sectors: ${warningDevices.join(', ')}. Check their SMART health.`;
-        driveHealthIcon = <Popup content={message} trigger={link}/>;
+        driveHealthIcon = <Tooltip label={message}>{link}</Tooltip>;
     }
 
     // Power issues, this is always displayed if detected.
     const {underVoltage, overCurrent} = usePowerStats();
     let powerIcon;
     if (underVoltage || overCurrent) {
-        const name = underVoltage ? 'power cord' : 'lightning';
-        const icon = <Icon name={name} size='large' color={highWarningColor}/>;
+        const icon = underVoltage
+            ? <Icon component={IconPlugOff} size='large' style={{color: colorVar(highWarningColor)}}
+                    label='Under-voltage warning'/>
+            : <Icon name='lightning' size='large' style={{color: colorVar(highWarningColor)}}
+                    label='Over-current warning'/>;
         const message = underVoltage
             ? 'Under-voltage detected! Your power supply is insufficient!'
             : 'Over-current detected! Your peripherals are using too much power!';
-        powerIcon = <Popup content={message} trigger={icon}/>;
+        powerIcon = <Tooltip label={message}><span>{icon}</span></Tooltip>;
     }
 
     // Display the temperature icon first because it can cause the system to throttle.  The rest are in order of effects
@@ -269,15 +324,14 @@ export function NavBar() {
     }
     const processingIcon = processingLink &&
         <Link to={processingLink}>
-            <Icon loading name='circle notch' size='large'/>
+            <Icon loading name='circle notch' size='large' label='File worker busy'/>
         </Link>;
 
     let apiDownIcon;
     if (window.apiDown) {
-        apiDownIcon = <Popup
-            content='API is not responding'
-            trigger={<Icon name='plug' color={highWarningColor}/>}
-        />
+        apiDownIcon = <Tooltip label='API is not responding'>
+            <span><Icon name='plug' style={{color: colorVar(highWarningColor)}} label='API is not responding'/></span>
+        </Tooltip>
     }
 
     // Upgrade available notification - only show on native (non-Docker) installs and when WROL Mode is disabled
@@ -286,12 +340,12 @@ export function NavBar() {
         const commitsBehind = status.commits_behind || 0;
         const branch = status.git_branch || 'unknown';
         const icon = <Link to='/admin/settings#upgrade'>
-            <Icon name='arrow alternate circle up' size='large' color='green'/>
+            <Icon name='arrow alternate circle up' size='large' style={{color: 'var(--green)'}}
+                  label='Upgrade available'/>
         </Link>;
-        upgradeIcon = <Popup
-            content={`Upgrade available: ${commitsBehind} commit(s) behind on ${branch}`}
-            trigger={icon}
-        />;
+        upgradeIcon = <Tooltip label={`Upgrade available: ${commitsBehind} commit(s) behind on ${branch}`}>
+            {icon}
+        </Tooltip>;
     }
 
     const icons = <React.Fragment>
@@ -308,27 +362,23 @@ export function NavBar() {
 
     return <>
         <Media between={['mobile', 'tablet']}>
-            <Menu {...i} attached='top' color={navColor} id='global_navbar'>
+            <nav className='wrolpi-navbar' id='global_navbar'
+                 style={{background: `var(--${navColor})`, color: 'var(--btn-text)'}}>
                 {homeLink}
-                <Menu.Menu position='right'>
+                <div className='wrolpi-navbar-right'>
                     {icons}
                     <SearchIconButton/>
-                    <Dropdown item icon="bars">
-                        <Dropdown.Menu>
-                            {allLinks.map(i => <MenuLink link={i} key={i.key}/>)}
-                            {rightLinks.map(i => <MenuLink link={i} key={i.key}/>)}
-                        </Dropdown.Menu>
-                    </Dropdown>
-                </Menu.Menu>
-            </Menu>
+                    <MobileMenu links={[...allLinks, ...rightLinks]}/>
+                </div>
+            </nav>
         </Media>
         <Media greaterThanOrEqual='tablet'>
-            <DesktopNav i={i} navColor={navColor} homeLink={homeLink} icons={icons}/>
+            <DesktopNav navColor={navColor} homeLink={homeLink} icons={icons}/>
         </Media>
     </>
 }
 
-function DesktopNav({i, navColor, homeLink, icons}) {
+function DesktopNav({navColor, homeLink, icons}) {
     const containerRef = React.useRef(null);
     const homeRef = React.useRef(null);
     const rightMenuRef = React.useRef(null);
@@ -343,7 +393,8 @@ function DesktopNav({i, navColor, homeLink, icons}) {
 
     return (
         <div ref={containerRef}>
-            <Menu {...i} attached='top' color={navColor} id='global_navbar'>
+            <nav className='wrolpi-navbar' id='global_navbar'
+                 style={{background: `var(--${navColor})`, color: 'var(--btn-text)'}}>
                 <span ref={homeRef} style={{display: 'contents'}}>{homeLink}</span>
                 {(isReady ? visibleLinks : allLinks).map((link, idx) => (
                     <span
@@ -355,16 +406,16 @@ function DesktopNav({i, navColor, homeLink, icons}) {
                     </span>
                 ))}
                 {!isReady && <span ref={moreRef} style={{visibility: 'hidden', flexShrink: 0}}>
-                    <Dropdown item text='More'><Dropdown.Menu/></Dropdown>
+                    <button type='button' className='wrolpi-navbar-link wrolpi-navbar-link-button'>More</button>
                 </span>}
                 {isReady && overflowLinks.length > 0 &&
                     <DropdownLinks link={{text: 'More', key: 'more', links: overflowLinks}}/>}
-                <div ref={rightMenuRef} className='right menu'>
+                <div ref={rightMenuRef} className='wrolpi-navbar-right'>
                     {icons}
                     <SearchIconButton/>
                     {rightLinks.map(i => <MenuLink link={i} key={i.key}/>)}
                 </div>
-            </Menu>
+            </nav>
         </div>
     );
 }
diff --git a/app/src/components/Playlists.js b/app/src/components/Playlists.js
index 195e3529..158807e7 100644
--- a/app/src/components/Playlists.js
+++ b/app/src/components/Playlists.js
@@ -1,9 +1,19 @@
 import React, {useEffect, useState} from "react";
 import {Link, Route, Routes, useNavigate, useParams} from "react-router";
-import {Grid, Image, Input, Message} from "semantic-ui-react";
-import {toast} from "./ui";
-
-import {Button, Form, Header, Icon, Loader, Modal, Segment, Table} from "./Theme";
+import {IconMapPin} from "@tabler/icons-react";
+import {
+    Button,
+    Group,
+    Header,
+    Icon,
+    Loading,
+    Message,
+    Modal,
+    Panel,
+    Table,
+    TextInput,
+    toast,
+} from "./ui";
 import {
     APIButton,
     BackButton,
@@ -35,7 +45,6 @@ import {
     setPlaylistTag,
     updatePlaylist,
 } from "../api";
-import {ThemeContext} from "../contexts/contexts";
 import {TagsSelector} from "../Tags";
 
 
@@ -119,39 +128,36 @@ export function PlaylistsPage() {
         }
     };
 
-    const header = <div style={{marginBottom: '1em'}}>
-        <Grid stackable columns={2}>
-            <Grid.Row>
-                <Grid.Column>
-                    <SearchInput
-                        placeholder='Name filter...'
-                        size='large'
-                        searchStr={searchStr}
-                        disabled={!Array.isArray(playlists) || playlists.length === 0}
-                        onClear={() => setSearchStr('')}
-                        onChange={setSearchStr}
-                        onSubmit={null}
-                        inputRef={searchInputRef}
-                    />
-                </Grid.Column>
-                <Grid.Column textAlign='right'>
-                    <Button secondary onClick={() => setModalOpen(true)}>New Playlist</Button>
-                </Grid.Column>
-            </Grid.Row>
-        </Grid>
-    </div>;
+    const header = <Group justify='space-between' align='flex-end' wrap='wrap' mb='1em'>
+        <SearchInput
+            placeholder='Name filter...'
+            size='large'
+            searchStr={searchStr}
+            disabled={!Array.isArray(playlists) || playlists.length === 0}
+            onClear={() => setSearchStr('')}
+            onChange={setSearchStr}
+            onSubmit={null}
+            inputRef={searchInputRef}
+        />
+        <Button role='primary' onClick={() => setModalOpen(true)}>New Playlist</Button>
+    </Group>;
 
     const createModal = <Modal open={modalOpen} onClose={() => setModalOpen(false)} size='tiny'>
         <Modal.Header>New Playlist</Modal.Header>
         <Modal.Content>
-            <Form onSubmit={handleCreate}>
-                <Form.Field>
-                    <label>Name</label>
-                    <Input autoFocus placeholder='Playlist name...' value={name}
-                           onChange={(e, {value}) => setName(value)}/>
-                </Form.Field>
-                <Form.Field>
-                    <label>
+            <form onSubmit={e => {
+                e.preventDefault();
+                handleCreate();
+            }}>
+                <TextInput
+                    autoFocus
+                    label='Name'
+                    placeholder='Playlist name...'
+                    value={name}
+                    onChange={(e) => setName(e.currentTarget.value)}
+                />
+                <div style={{marginTop: '1em'}}>
+                    <label style={{display: 'flex', alignItems: 'center', gap: '0.3em', marginBottom: '0.3em'}}>
                         Tag
                         <InfoPopup content='Optional. A tagged playlist lives under its tag in the
                             Playlists Directory.'/>
@@ -162,12 +168,12 @@ export function PlaylistsPage() {
                         onAdd={setTagName}
                         onRemove={() => setTagName(null)}
                     />
-                </Form.Field>
-            </Form>
+                </div>
+            </form>
         </Modal.Content>
         <Modal.Actions>
-            <Button onClick={() => setModalOpen(false)}>Cancel</Button>
-            <Button primary disabled={!name.trim()} onClick={handleCreate}>Create</Button>
+            <Button role='cancel' onClick={() => setModalOpen(false)}>Cancel</Button>
+            <Button role='save' disabled={!name.trim()} onClick={handleCreate}>Create</Button>
         </Modal.Actions>
     </Modal>;
 
@@ -185,22 +191,24 @@ export function PlaylistsPage() {
 }
 
 
-// Icon (name + color) for a playlist item.  File items use the FileGroup's mimetype/model icon
-// and color (video, pdf, ebook, image, ...) so they match the rest of the UI; zim/url are fixed.
-function itemIcon(item) {
+// Icon for a playlist item.  File items use FileGroup's mimetype/model icon and color (video,
+// pdf, ebook, image, ...) so they match the rest of the UI; zim/url are fixed.
+function ItemIcon({item}) {
     if (item.item_kind === 'file' && item.file_group) {
         const fg = item.file_group;
         const lowerPath = (fg.primary_path || '').toLowerCase();
-        return {name: mimetypeIconName(fg.mimetype, lowerPath), color: mimetypeColor(fg.mimetype, lowerPath)};
+        const name = mimetypeIconName(fg.mimetype, lowerPath);
+        const color = mimetypeColor(fg.mimetype, lowerPath);
+        return <Icon name={name} size='large' style={{color: `var(--${color})`}}/>;
     }
-    if (item.item_kind === 'zim') return {name: 'book'};
+    if (item.item_kind === 'zim') return <Icon name='book' size='large'/>;
     if (item.item_kind === 'url') {
         // A map-location URL (e.g. /map?lat=&lon=) gets a map marker; other URLs get the link icon.
         const u = (item.url || '').toLowerCase();
-        if (u.startsWith('/map')) return {name: 'map marker alternate'};
-        return {name: 'linkify'};
+        if (u.startsWith('/map')) return <Icon component={IconMapPin} size='large'/>;
+        return <Icon name='linkify' size='large'/>;
     }
-    return {name: 'file'};
+    return <Icon name='file' size='large'/>;
 }
 
 
@@ -278,13 +286,13 @@ function ItemTitle({item, label}) {
 // The ordered items table, shared by the view and edit pages.  When `editable`, the reorder/remove
 // action buttons (and their column) are shown; otherwise the table is read-only.
 function PlaylistItemsTable({items, editable, onMove, onRemove}) {
-    return <Table unstackable celled>
+    return <Table>
         <Table.Header>
             <Table.Row>
-                <Table.HeaderCell collapsing>#</Table.HeaderCell>
-                <Table.HeaderCell collapsing>Item</Table.HeaderCell>
+                <Table.HeaderCell>#</Table.HeaderCell>
+                <Table.HeaderCell>Item</Table.HeaderCell>
                 <Table.HeaderCell>Title</Table.HeaderCell>
-                {editable && <Table.HeaderCell collapsing/>}
+                {editable && <Table.HeaderCell/>}
             </Table.Row>
         </Table.Header>
         <Table.Body>
@@ -292,23 +300,23 @@ function PlaylistItemsTable({items, editable, onMove, onRemove}) {
                 const label = itemLabel(item);
                 const poster = item.item_kind === 'file' && item.file_group
                     ? findPosterPath(item.file_group) : null;
-                return <Table.Row key={item.id} verticalAlign='middle'>
-                    <Table.Cell collapsing>{String(index + 1).padStart(2, '0')}</Table.Cell>
-                    <Table.Cell collapsing textAlign='center' style={{width: '90px'}}>
+                return <Table.Row key={item.id}>
+                    <Table.Cell>{String(index + 1).padStart(2, '0')}</Table.Cell>
+                    <Table.Cell style={{width: '90px', textAlign: 'center'}}>
                         {poster
-                            ? <Image src={`/media/${encodeMediaPath(poster)}`} alt=''
-                                     centered style={{maxHeight: '45px', maxWidth: '80px', width: 'auto'}}/>
-                            : <Icon {...itemIcon(item)} size='large'/>}
+                            ? <img alt='' src={`/media/${encodeMediaPath(poster)}`}
+                                   style={{maxHeight: '45px', maxWidth: '80px', width: 'auto', display: 'block', margin: '0 auto'}}/>
+                            : <ItemIcon item={item}/>}
                     </Table.Cell>
                     <Table.Cell>
                         <ItemTitle item={item} label={label}/>
                     </Table.Cell>
-                    {editable && <Table.Cell collapsing textAlign='right'>
-                        <Button icon='arrow up' size='mini' disabled={index === 0}
+                    {editable && <Table.Cell style={{textAlign: 'right', whiteSpace: 'nowrap'}}>
+                        <Button icon='arrow up' size='xs' disabled={index === 0}
                                 onClick={() => onMove(index, -1)}/>
-                        <Button icon='arrow down' size='mini' disabled={index === items.length - 1}
+                        <Button icon='arrow down' size='xs' disabled={index === items.length - 1}
                                 onClick={() => onMove(index, 1)}/>
-                        <Button icon='trash' color='red' size='mini'
+                        <Button role='danger' icon='trash' size='xs'
                                 onClick={() => onRemove(item.id)}/>
                     </Table.Cell>}
                 </Table.Row>;
@@ -323,7 +331,6 @@ function PlaylistItemsTable({items, editable, onMove, onRemove}) {
 export function PlaylistViewPage() {
     const {playlistId} = useParams();
     const {playlist} = usePlaylist(playlistId);
-    const {t} = React.useContext(ThemeContext);
 
     useTitle(playlist && playlist.name ? `${playlist.name} Playlist` : 'Playlist');
 
@@ -331,7 +338,7 @@ export function PlaylistViewPage() {
         return <ErrorMessage>Could not fetch playlist</ErrorMessage>;
     }
     if (playlist === null) {
-        return <Loader active inline='centered'/>;
+        return <Loading/>;
     }
 
     const items = playlist.items || [];
@@ -345,10 +352,10 @@ export function PlaylistViewPage() {
                 <Icon name='edit' style={{marginLeft: '0.5em'}}/>
             </Link>
         </Header>
-        {playlist.description && <p {...t}>{playlist.description}</p>}
+        {playlist.description && <p>{playlist.description}</p>}
 
         {items.length === 0
-            ? <Message><Message.Header>This playlist is empty</Message.Header></Message>
+            ? <Message title='This playlist is empty'/>
             : <PlaylistItemsTable items={items} editable={false}/>}
     </>;
 }
@@ -385,7 +392,7 @@ export function PlaylistEditPage() {
         return <ErrorMessage>Could not fetch playlist</ErrorMessage>;
     }
     if (playlist === null) {
-        return <Loader active inline='centered'/>;
+        return <Loading/>;
     }
 
     const items = playlist.items || [];
@@ -463,7 +470,7 @@ export function PlaylistEditPage() {
     };
 
     const deleteButton = <APIButton
-        color='red'
+        role='danger'
         size='small'
         confirmContent='Are you sure you want to delete this playlist? Its directory will be removed.'
         confirmButton='Delete'
@@ -477,7 +484,7 @@ export function PlaylistEditPage() {
         type="button"
         size='small'
         onClick={() => setTagModalOpen(true)}
-        color='violet'
+        role='primary'
         disabled={!editable}
         style={{marginTop: '1em'}}
     >Tag</Button>;
@@ -504,47 +511,35 @@ export function PlaylistEditPage() {
             appliedTagName={playlist.tag_name}
             onSubmit={handleSave}
         >
-            <Grid.Row>
-                <Grid.Column width={8}>
-                    <Form.Field>
-                        <label>Playlist Name</label>
-                        <Input
-                            placeholder='Playlist name...'
-                            value={name}
-                            disabled={!editable}
-                            onChange={(e, {value}) => setName(value)}
-                        />
-                    </Form.Field>
-                </Grid.Column>
-                <Grid.Column width={8}>
-                    <Form.Field>
-                        <label>
-                            Directory
-                            <InfoPopup content='Where the playlist lives on disk. By default it is
-                                managed automatically in the Playlists Directory (under its tag, if
-                                tagged); choose a different directory to manage it manually.'/>
-                        </label>
-                        <DirectorySearch
-                            value={directory}
-                            disabled={!editable}
-                            onSelect={value => setDirectory(value || '')}
-                        />
-                    </Form.Field>
-                </Grid.Column>
-            </Grid.Row>
-            <Grid.Row>
-                <Grid.Column>
-                    <Form.Field>
-                        <label>Description</label>
-                        <Input
-                            placeholder='Optional description...'
-                            value={description}
-                            disabled={!editable}
-                            onChange={(e, {value}) => setDescription(value)}
-                        />
-                    </Form.Field>
-                </Grid.Column>
-            </Grid.Row>
+            <TextInput
+                label='Playlist Name'
+                placeholder='Playlist name...'
+                value={name}
+                disabled={!editable}
+                onChange={(e) => setName(e.currentTarget.value)}
+            />
+            <div style={{marginTop: '1em'}}>
+                <label style={{display: 'flex', alignItems: 'center', gap: '0.3em', marginBottom: '0.3em'}}>
+                    Directory
+                    <InfoPopup content='Where the playlist lives on disk. By default it is
+                        managed automatically in the Playlists Directory (under its tag, if
+                        tagged); choose a different directory to manage it manually.'/>
+                </label>
+                <DirectorySearch
+                    value={directory}
+                    disabled={!editable}
+                    onSelect={value => setDirectory(value || '')}
+                />
+            </div>
+            <div style={{marginTop: '1em'}}>
+                <TextInput
+                    label='Description'
+                    placeholder='Optional description...'
+                    value={description}
+                    disabled={!editable}
+                    onChange={(e) => setDescription(e.currentTarget.value)}
+                />
+            </div>
         </CollectionEditForm>
 
         {/* Tag Modal */}
@@ -559,34 +554,34 @@ export function PlaylistEditPage() {
         />
 
         {/* Items Segment */}
-        <Segment>
+        <Panel>
             <Header as='h1'>Items</Header>
 
             {items.length === 0
-                ? <Message>
-                    <Message.Header>This playlist is empty</Message.Header>
-                    {editable && <Message.Content>Add a link below.</Message.Content>}
+                ? <Message title='This playlist is empty'>
+                    {editable && 'Add a link below.'}
                 </Message>
                 : <PlaylistItemsTable items={items} editable={editable} onMove={move} onRemove={handleRemove}/>}
 
             <Header as='h4'>Add a link</Header>
-            <Form onSubmit={handleAddUrl}>
-                <Form.Group>
-                    <Form.Field width={8}>
-                        <Input placeholder='URL (e.g. /map?lat=40.76&lon=-111.89&z=10)'
-                               value={url} disabled={!editable}
-                               onChange={(e, {value}) => setUrl(value)}/>
-                    </Form.Field>
-                    <Form.Field width={6}>
-                        <Input placeholder='Title (optional)' value={urlTitle} disabled={!editable}
-                               onChange={(e, {value}) => setUrlTitle(value)}/>
-                    </Form.Field>
-                    <Form.Field>
-                        <Button primary type='submit' disabled={!editable || !url.trim()}>Add</Button>
-                    </Form.Field>
-                </Form.Group>
-            </Form>
-        </Segment>
+            <form onSubmit={e => {
+                e.preventDefault();
+                handleAddUrl();
+            }}>
+                <Group align='flex-end' wrap='wrap'>
+                    <TextInput
+                        style={{flex: '2 1 300px'}}
+                        placeholder='URL (e.g. /map?lat=40.76&lon=-111.89&z=10)'
+                        value={url} disabled={!editable}
+                        onChange={(e) => setUrl(e.currentTarget.value)}/>
+                    <TextInput
+                        style={{flex: '1 1 200px'}}
+                        placeholder='Title (optional)' value={urlTitle} disabled={!editable}
+                        onChange={(e) => setUrlTitle(e.currentTarget.value)}/>
+                    <Button role='primary' type='submit' disabled={!editable || !url.trim()}>Add</Button>
+                </Group>
+            </form>
+        </Panel>
     </>;
 }
 
diff --git a/app/src/components/Theme.test.js b/app/src/components/Theme.test.js
deleted file mode 100644
index 8389e509..00000000
--- a/app/src/components/Theme.test.js
+++ /dev/null
@@ -1,109 +0,0 @@
-import React from 'react';
-import {Button, Modal, Progress} from './Theme';
-import {renderInDarkMode, renderInLightMode} from '../test-utils';
-
-// All semantic-ui colors.
-const allColors = ['red', 'orange', 'yellow', 'olive', 'green', 'teal', 'blue', 'violet', 'purple', 'pink', 'brown', 'grey'];
-
-// Light bar colors that always need dark percent text (light bars in any theme).
-const lightBarColors = ['yellow', 'olive', 'teal'];
-// Bar colors that need dark percent text only in dark mode (inverted makes bar lighter).
-const darkModeLightBarColors = ['grey', 'blue'];
-
-describe('Button ref forwarding', () => {
-    // Regression: SButton is a class component, so forwarding a ref straight to it resolves to the class instance
-    // (no `.contains`). Semantic UI's Modal/Popup Portal calls `node.contains(...)` on the trigger's ref during
-    // handleDocumentClick, throwing "node.contains is not a function". The forwarded ref must be the DOM <button>.
-    it('resolves a forwarded ref to the underlying DOM element', () => {
-        const ref = React.createRef();
-        renderInLightMode(<Button ref={ref} content='Click'/>);
-
-        expect(ref.current).toBeInstanceOf(HTMLElement);
-        expect(typeof ref.current.contains).toBe('function');
-        expect(ref.current.tagName).toBe('BUTTON');
-    });
-
-    it('does not throw when a Button is used as a controlled Modal trigger and the document is clicked', () => {
-        // Reproduces the Control page crash: an open Modal whose trigger is a themed Button. A document click
-        // invokes the Portal's handleDocumentClick -> doesNodeContainClick(triggerRef.current, e).
-        renderInLightMode(
-            <Modal open trigger={<Button content='Open'/>}>
-                <Modal.Content>content</Modal.Content>
-            </Modal>
-        );
-
-        expect(() => {
-            document.body.dispatchEvent(new MouseEvent('click', {bubbles: true}));
-        }).not.toThrow();
-    });
-});
-
-describe('Progress component theme support', () => {
-    describe('dark mode', () => {
-        it('adds inverted-progress-text class for label readability', () => {
-            const {container} = renderInDarkMode(
-                <Progress percent={39} progress indicating color='violet'>
-                    2.1 GB / 5.3 GB
-                </Progress>
-            );
-
-            const progressEl = container.querySelector('.ui.progress');
-            expect(progressEl).toHaveClass('inverted-progress-text');
-
-            const progressLabel = container.querySelector('.bar > .progress');
-            expect(progressLabel).toHaveTextContent('39%');
-
-            const label = container.querySelector('.ui.progress > .label');
-            expect(label).toHaveTextContent('2.1 GB / 5.3 GB');
-        });
-
-        it('does NOT add inverted-progress-text in light mode', () => {
-            const {container} = renderInLightMode(
-                <Progress percent={39} progress indicating color='violet'>
-                    2.1 GB / 5.3 GB
-                </Progress>
-            );
-
-            const progressEl = container.querySelector('.ui.progress');
-            expect(progressEl).not.toHaveClass('inverted-progress-text');
-        });
-    });
-
-    describe('percent text contrast per color', () => {
-        allColors.forEach(color => {
-            it(`${color} bar has readable percent text in light mode`, () => {
-                const {container} = renderInLightMode(
-                    <Progress percent={50} progress color={color}/>
-                );
-
-                const progressLabel = container.querySelector('.bar > .progress');
-                expect(progressLabel).toBeInTheDocument();
-                expect(progressLabel).toHaveTextContent('50%');
-
-                const progressEl = container.querySelector('.ui.progress');
-                if (lightBarColors.includes(color)) {
-                    expect(progressEl).toHaveClass('light-bar-progress-text');
-                } else {
-                    expect(progressEl).not.toHaveClass('light-bar-progress-text');
-                }
-            });
-
-            it(`${color} bar has readable percent text in dark mode`, () => {
-                const {container} = renderInDarkMode(
-                    <Progress percent={50} progress color={color}/>
-                );
-
-                const progressLabel = container.querySelector('.bar > .progress');
-                expect(progressLabel).toBeInTheDocument();
-                expect(progressLabel).toHaveTextContent('50%');
-
-                const progressEl = container.querySelector('.ui.progress');
-                if (lightBarColors.includes(color) || darkModeLightBarColors.includes(color)) {
-                    expect(progressEl).toHaveClass('light-bar-progress-text');
-                } else {
-                    expect(progressEl).not.toHaveClass('light-bar-progress-text');
-                }
-            });
-        });
-    });
-});
diff --git a/app/src/components/Theme.tsx b/app/src/components/Theme.tsx
index 2d325f30..3c5d6625 100644
--- a/app/src/components/Theme.tsx
+++ b/app/src/components/Theme.tsx
@@ -1,99 +1,5 @@
-import React, {useContext, useEffect, useState, forwardRef, HTMLAttributes, CSSProperties} from 'react';
+import React, {useEffect, useState} from 'react';
 import {ThemeContext} from "../contexts/contexts";
-import {
-    Accordion as SAccordion,
-    AccordionContent as SAccordionContent,
-    AccordionTitle as SAccordionTitle,
-    Breadcrumb as SBreadcrumb,
-    Button as SButton,
-    ButtonGroup as SButtonGroup,
-    Card as SCard,
-    Divider as SDivider,
-    Form as SForm,
-    FormField as SFormField,
-    FormGroup as SFormGroup,
-    FormInput as SFormInput,
-    Header as SHeader,
-    Icon as SIcon,
-    List as SList,
-    ListContent as SListContent,
-    ListDescription as SListDescription,
-    ListHeader as SListHeader,
-    ListIcon as SListIcon,
-    ListItem as SListItem,
-    Loader as SLoader,
-    Menu as SMenu,
-    MenuItem as SMenuItem,
-    MenuHeader as SMenuHeader,
-    MenuMenu as SMenuMenu,
-    Modal as SModal,
-    ModalActions as SModalActions,
-    ModalContent as SModalContent,
-    ModalDescription as SModalDescription,
-    ModalHeader as SModalHeader,
-    Placeholder as SPlaceholder,
-    Popup as SPopup,
-    Progress as SProgress,
-    Ref as SRef,
-    Segment as SSegment,
-    Statistic as SStatistic,
-    StatisticGroup as SStatisticGroup,
-    Tab as STab,
-    Table as STable,
-    TableBody as STableBody,
-    TableCell as STableCell,
-    TableFooter as STableFooter,
-    TableHeader as STableHeader,
-    TableHeaderCell as STableHeaderCell,
-    TableRow as STableRow,
-    TabPane as STabPane,
-    TextArea as STextArea,
-    AccordionContentProps,
-    AccordionProps,
-    AccordionTitleProps,
-    BreadcrumbProps,
-    ButtonProps,
-    ButtonGroupProps,
-    CardProps as SCardProps,
-    DividerProps,
-    FormProps,
-    FormFieldProps,
-    FormGroupProps,
-    FormInputProps,
-    HeaderProps,
-    IconProps,
-    ListProps,
-    ListItemProps,
-    ListIconProps,
-    ListContentProps,
-    ListHeaderProps,
-    ListDescriptionProps,
-    LoaderProps,
-    MenuProps,
-    MenuItemProps,
-    MenuMenuProps,
-    ModalProps,
-    ModalActionsProps,
-    ModalContentProps,
-    ModalDescriptionProps,
-    ModalHeaderProps,
-    PlaceholderProps,
-    PopupProps,
-    ProgressProps,
-    SegmentProps,
-    StatisticProps,
-    StatisticGroupProps,
-    TabProps,
-    TableProps,
-    TableBodyProps,
-    TableCellProps,
-    TableFooterProps,
-    TableHeaderProps,
-    TableHeaderCellProps,
-    TableRowProps,
-    TabPaneProps,
-    TextAreaProps,
-} from "semantic-ui-react";
 import {MantineProvider} from "@mantine/core";
 import {Notifications} from "@mantine/notifications";
 import {cssVariablesResolver, mantineTheme} from "../themes/mantine";
@@ -101,7 +7,6 @@ import {
     amberTheme,
     darkTheme,
     defaultTheme,
-    explicitOnlyThemes,
     isDarkTheme,
     isThemeName,
     lightTheme,
@@ -114,13 +19,11 @@ import {
     themeNames,
     themeSessionKey,
 } from "../themes/names";
-import {ColorToSemanticHexColor} from "./Vars";
 import _ from "lodash";
 import {ThemeContextValue, ThemeName, SavedThemeName} from "../types/theme";
 
-// Theme names and picker choices live in themes/names so the component library can use
-// them without importing this module (which still pulls in Semantic UI).  Re-exported
-// here because most call sites already import them from Theme.
+// Theme names and picker choices live in themes/names, and are re-exported here because
+// most call sites already import them from Theme.
 export {
     amberTheme,
     darkTheme,
@@ -289,26 +192,7 @@ export function ThemeProvider({children, ...props}: ThemeProviderProps) {
 
     const dark = isDarkTheme(theme);
 
-    // Compatibility layer for components which have not been migrated to tokens yet.  Semantic
-    // has no concept of the night/amber themes, so they reuse its dark treatment while pulling
-    // their colors from the tokens.  These values disappear with the last Semantic component.
-    const i = dark ? {inverted: true} : {inverted: undefined};
-    const inverted = dark ? 'inverted' : '';
-    let s: {style?: CSSProperties} = {};
-    let t: {style?: CSSProperties} = {};
-    if (theme === darkTheme) {
-        s = {style: {backgroundColor: '#1B1C1D', color: '#dddddd'}};
-        t = {style: {color: '#eeeeee'}};
-    } else if (explicitOnlyThemes.includes(theme)) {
-        s = {style: {backgroundColor: 'var(--panel)', color: 'var(--text)'}};
-        t = {style: {color: 'var(--text)'}};
-    }
-
     const themeValue: ThemeContextValue = {
-        i, // Used for Semantic elements which support "inverted".
-        s, // Used to invert the style some elements.
-        t, // Used to invert text.
-        inverted, // Used to add "invert" to className.
         theme,
         savedTheme,
         isDark: dark,
@@ -336,526 +220,16 @@ export function ThemeProvider({children, ...props}: ThemeProviderProps) {
         </MantineProvider>
     </ThemeContext.Provider>
 }
-
-// Simple wrappers for Semantic UI elements to use the current theme.
-
-const invertedNull = <T extends {inverted?: boolean | null}>(props: T): T => {
-    if (props['inverted'] === true) {
-        return {...props, inverted: null};
-    }
-    return props;
-}
-
-const defaultGrey = <T extends object>(props: T, inverted: boolean): T => {
-    // Some elements look softer when grey, use grey only if another color is not provided.
-    if (inverted) {
-        return {color: 'grey', ...props} as T;
-    }
-    return props;
-}
-
-// ----------------------------------------------------------------------------
-// Accordion Compound Component
-// ----------------------------------------------------------------------------
-
-type AccordionTitleComponent = React.FC<AccordionTitleProps>;
-type AccordionContentComponent = React.FC<AccordionContentProps>;
-
-interface AccordionComponent extends React.FC<AccordionProps> {
-    Title: AccordionTitleComponent;
-    Content: AccordionContentComponent;
-}
-
-const AccordionTitle: AccordionTitleComponent = (props) => {
-    return <SAccordionTitle {...props}/>
-};
-
-const AccordionContent: AccordionContentComponent = (props) => {
-    return <SAccordionContent {...props}/>
-};
-
-const AccordionBase: React.FC<AccordionProps> = (props) => {
-    const {i, inverted} = useContext(ThemeContext);
-    const mergedProps = defaultGrey({...i, ...props}, !!inverted);
-    return <SAccordion {...mergedProps}/>
-};
-
-export const Accordion: AccordionComponent = Object.assign(AccordionBase, {
-    Title: AccordionTitle,
-    Content: AccordionContent,
-});
-
-// ----------------------------------------------------------------------------
-// Button Compound Component
-// ----------------------------------------------------------------------------
-
-type ButtonGroupComponent = React.FC<ButtonGroupProps>;
-
-interface ButtonComponent extends React.ForwardRefExoticComponent<ButtonProps & React.RefAttributes<any>> {
-    Group: ButtonGroupComponent;
-}
-
-const ButtonGroup: ButtonGroupComponent = (props) => {
-    return <SButtonGroup {...props}/>
-};
-
-const ButtonBase = forwardRef<any, ButtonProps>((props, ref) => {
-    const {i, inverted} = useContext(ThemeContext);
-    const mergedProps = defaultGrey({...i, ...props}, !!inverted);
-    // SButton is a class component, so a forwarded `ref` would resolve to the class instance rather than the DOM
-    // node. Semantic UI's Modal/Popup use the trigger's ref with `node.contains(...)`, which throws on a non-DOM
-    // value. Wrap in Ref (findDOMNode) so the forwarded ref always resolves to the underlying <button> element.
-    if (ref) {
-        return <SRef innerRef={ref}><SButton {...mergedProps}/></SRef>
-    }
-    return <SButton {...mergedProps}/>
-});
-ButtonBase.displayName = 'ButtonBase';
-
-export const Button: ButtonComponent = Object.assign(ButtonBase, {
-    Group: ButtonGroup,
-});
-
-export function Divider(props: DividerProps) {
-    const {i} = useContext(ThemeContext);
-    return <SDivider {...i} {...props}/>
-}
-
-export function Header(props: HeaderProps) {
-    const {t} = useContext(ThemeContext);
-    // Merge the caller's style on top of the theme's text style; a bare `{...props}`
-    // would let an incoming `style` prop replace (and drop) the theme's text color.
-    return <SHeader {...t} {...props} style={{...t.style, ...props.style}}/>
-}
-
-export function Icon(props: IconProps) {
-    const {i} = useContext(ThemeContext);
-    return <SIcon {...i} {...props}/>
-}
-
-export function Loader(props: LoaderProps) {
-    const {i} = useContext(ThemeContext);
-    return <SLoader {...i} {...props}/>
-}
-
-// Menu is a compound component (Menu.Item / Menu.Header / Menu.Menu) so callers get the same API as Semantic's
-// Menu while inheriting the theme.  The parent menu is `inverted` in dark mode so item text stays readable.
-const MenuBase: React.FC<MenuProps> = (props) => {
-    const {i} = useContext(ThemeContext);
-    return <SMenu {...i} {...props}/>;
-};
-
-const MenuItem: React.FC<MenuItemProps> = (props) => <SMenuItem {...props}/>;
-const MenuHeader: React.FC<MenuItemProps> = (props) => <SMenuHeader {...props}/>;
-const MenuMenu: React.FC<MenuMenuProps> = (props) => <SMenuMenu {...props}/>;
-
-interface MenuComponent extends React.FC<MenuProps> {
-    Item: React.FC<MenuItemProps>;
-    Header: React.FC<MenuItemProps>;
-    Menu: React.FC<MenuMenuProps>;
-}
-
-export const Menu: MenuComponent = Object.assign(MenuBase, {
-    Item: MenuItem,
-    Header: MenuHeader,
-    Menu: MenuMenu,
-});
-
-export function Placeholder(props: PlaceholderProps) {
-    const {i} = useContext(ThemeContext);
-    return <SPlaceholder {...i} {...props}/>
-}
-
-export function Popup(props: PopupProps) {
-    const {i} = useContext(ThemeContext);
-    return <SPopup {...i} style={{border: '1px solid grey'}} {...props}/>
-}
-
-// Bar colors that always need dark percent text (light bars in any theme).
-const PROGRESS_BAR_COLORS = ['yellow', 'olive', 'teal'];
-// Bar colors that need dark percent text only in dark mode (inverted makes bar lighter).
-const DARK_MODE_PROGRESS_BAR_COLORS = ['grey', 'blue'];
-
-export function Progress(props: ProgressProps) {
-    const {i, inverted} = useContext(ThemeContext);
-    const classes = [props.className || ''];
-    if (inverted) classes.push('inverted-progress-text');
-    const color = props.color as string;
-    if (PROGRESS_BAR_COLORS.includes(color) || (inverted && DARK_MODE_PROGRESS_BAR_COLORS.includes(color))) {
-        classes.push('light-bar-progress-text');
-    }
-    return <SProgress {...i} {...props} className={classes.join(' ').trim()}/>
-}
-
-export function Segment(props: SegmentProps) {
-    const {i} = useContext(ThemeContext);
-    return <SSegment {...i} {...props}/>
-}
-
-// Table is now a compound component - see COMPOUND COMPONENTS section below
-
-export function TextArea(props: TextAreaProps) {
-    const {i} = useContext(ThemeContext);
-    const mergedProps = invertedNull({...i, ...props});
-    return <STextArea {...mergedProps}/>
-}
-
-// ============================================================================
-// COMPOUND COMPONENTS
-// ============================================================================
-
-// ----------------------------------------------------------------------------
-// Modal Compound Component
-// ----------------------------------------------------------------------------
-
-type ModalActionsComponent = React.FC<ModalActionsProps>;
-type ModalContentComponent = React.FC<ModalContentProps>;
-type ModalDescriptionComponent = React.FC<ModalDescriptionProps>;
-type ModalHeaderComponent = React.FC<ModalHeaderProps>;
-
-interface ModalComponent extends React.FC<ModalProps> {
-    Actions: ModalActionsComponent;
-    Content: ModalContentComponent;
-    Description: ModalDescriptionComponent;
-    Header: ModalHeaderComponent;
-}
-
-const ModalActions: ModalActionsComponent = (props) => {
-    const {inverted} = useContext(ThemeContext);
-    return <SModalActions {...props} className={`${inverted}`}/>
-};
-
-const ModalContent: ModalContentComponent = (props) => {
-    const {inverted} = useContext(ThemeContext);
-    return <SModalContent {...props} className={`${inverted}`}/>
-};
-
-const ModalDescription: ModalDescriptionComponent = (props) => {
-    const {inverted} = useContext(ThemeContext);
-    return <SModalDescription {...props} className={`${inverted}`}/>
-};
-
-const ModalHeader: ModalHeaderComponent = (props) => {
-    const {inverted} = useContext(ThemeContext);
-    return <SModalHeader {...props} className={`${inverted}`}>
-        {props.children}
-    </SModalHeader>
-};
-
-const ModalBase: React.FC<ModalProps> = (props) => {
-    const {inverted} = useContext(ThemeContext);
-    return <SModal {...props} className={`${inverted}`}/>
-};
-
-export const Modal: ModalComponent = Object.assign(ModalBase, {
-    Actions: ModalActions,
-    Content: ModalContent,
-    Description: ModalDescription,
-    Header: ModalHeader,
-});
-
-// ----------------------------------------------------------------------------
-// List Compound Component
-// ----------------------------------------------------------------------------
-// Semantic's List supports `inverted`; the inverted class on the parent handles the item text,
-// but List.Icon must also receive `inverted` so its color flips in dark mode (the parent's
-// inverted class alone does not restyle the icon).
-
-interface ListComponent extends React.FC<ListProps> {
-    Item: React.FC<ListItemProps>;
-    Icon: React.FC<ListIconProps>;
-    Content: React.FC<ListContentProps>;
-    Header: React.FC<ListHeaderProps>;
-    Description: React.FC<ListDescriptionProps>;
-}
-
-const ListBase: React.FC<ListProps> = (props) => {
-    const {i} = useContext(ThemeContext);
-    return <SList {...i} {...props}/>
-};
-
-const ListIcon: React.FC<ListIconProps> = (props) => {
-    const {i} = useContext(ThemeContext);
-    return <SListIcon {...i} {...props}/>
-};
-
-export const List: ListComponent = Object.assign(ListBase, {
-    Item: SListItem,
-    Icon: ListIcon,
-    Content: SListContent,
-    Header: SListHeader,
-    Description: SListDescription,
-});
-
-// ----------------------------------------------------------------------------
-// Confirm Component
-// ----------------------------------------------------------------------------
-
-export interface ConfirmProps {
-    open: boolean;
-    header?: string;
-    content?: string | React.ReactNode;
-    confirmButton?: string;
-    cancelButton?: string;
-    onConfirm?: () => void;
-    onCancel?: () => void;
-    onClose?: () => void;
-    size?: 'mini' | 'tiny' | 'small' | 'large' | 'fullscreen';
-}
-
-export const Confirm: React.FC<ConfirmProps> = ({
-    open,
-    header,
-    content,
-    confirmButton = 'OK',
-    cancelButton = 'Cancel',
-    onConfirm,
-    onCancel,
-    onClose,
-    size = 'tiny',
-}) => {
-    const {i} = useContext(ThemeContext);
-
-    return (
-        <Modal open={open} onClose={onClose} size={size} className="themed-confirm">
-            {header && <Modal.Header>{header}</Modal.Header>}
-            <Modal.Content>
-                {typeof content === 'string' ? <p>{content}</p> : content}
-            </Modal.Content>
-            <Modal.Actions>
-                <Button onClick={onCancel} {...i}>{cancelButton}</Button>
-                <Button onClick={onConfirm} color="green" {...i}>{confirmButton}</Button>
-            </Modal.Actions>
-        </Modal>
-    );
-};
-
-// ----------------------------------------------------------------------------
-// Form Compound Component
-// ----------------------------------------------------------------------------
-
-type FormFieldComponent = React.FC<FormFieldProps>;
-type FormGroupComponent = React.FC<FormGroupProps>;
-type FormInputComponent = React.FC<FormInputProps>;
-
-interface FormComponent extends React.FC<FormProps> {
-    Field: FormFieldComponent;
-    Group: FormGroupComponent;
-    Input: FormInputComponent;
-}
-
-const FormField: FormFieldComponent = (props) => {
-    const {i} = useContext(ThemeContext);
-    const mergedProps = invertedNull({...i, ...props});
-    return <SFormField {...mergedProps}/>
-};
-
-const FormGroup: FormGroupComponent = (props) => {
-    const {i} = useContext(ThemeContext);
-    const mergedProps = invertedNull({...i, ...props});
-    return <SFormGroup {...mergedProps}/>
-};
-
-const FormInput: FormInputComponent = (props) => {
-    const {i} = useContext(ThemeContext);
-    return <SFormInput {...i} {...props}/>
-};
-
-const FormBase: React.FC<FormProps> = (props) => {
-    const {i} = useContext(ThemeContext);
-    return <SForm {...i} {...props}/>
-};
-
-export const Form: FormComponent = Object.assign(FormBase, {
-    Field: FormField,
-    Group: FormGroup,
-    Input: FormInput,
-});
-
-// ----------------------------------------------------------------------------
-// Card Compound Component
-// ----------------------------------------------------------------------------
-
-interface CardIconProps extends HTMLAttributes<HTMLDivElement> {
-    onClick?: () => void;
-    children?: React.ReactNode;
-}
-
-type CardIconComponent = React.FC<CardIconProps>;
-
-interface CardProps extends Omit<SCardProps, 'color'> {
-    color?: string;
-}
-
-interface CardComponent extends React.FC<CardProps> {
-    Icon: CardIconComponent;
-}
-
-const CardIcon: CardIconComponent = ({onClick, children, ...props}) => {
-    const {inverted} = useContext(ThemeContext);
-    const cardIcon = <center className={`card-icon ${inverted}`} {...props}>{children}</center>;
-    if (onClick) {
-        return <div onClick={onClick} className='clickable'>
-            {cardIcon}
-        </div>
-    } else {
-        return cardIcon;
-    }
-};
-
-const CardBase: React.FC<CardProps> = ({color, ...props}) => {
-    const {inverted} = useContext(ThemeContext);
-
-    const style: CSSProperties = props.style || {};
-    const emphasisColor = ColorToSemanticHexColor(color);
-    if (emphasisColor) {
-        // Increase drop shadow to emphasize color.
-        const borderColor = inverted ? '#888' : '#ddd';
-        style.boxShadow = `0 0 0 2px ${borderColor}, 0 5px 0 0 ${emphasisColor}, 0 0px 3px 0 #d4d4d5`;
-    }
-    return <SCard {...props} style={style}/>
-};
-
-export const Card: CardComponent = Object.assign(CardBase, {
-    Icon: CardIcon,
-});
-
-// ----------------------------------------------------------------------------
-// Tab Compound Component
-// ----------------------------------------------------------------------------
-
-type TabPaneComponent = React.FC<TabPaneProps>;
-
-interface TabComponent extends React.FC<TabProps> {
-    Pane: TabPaneComponent;
-}
-
-const TabPane: TabPaneComponent = (props) => {
-    const {i} = useContext(ThemeContext);
-    return <STabPane {...i} {...props}/>
-};
-
-const TabBase: React.FC<TabProps> = (props) => {
-    const {i} = useContext(ThemeContext);
-    const mergedProps = invertedNull({...i, ...props});
-    return <STab {...mergedProps}/>
-};
-
-export const Tab: TabComponent = Object.assign(TabBase, {
-    Pane: TabPane,
-});
-
-// ----------------------------------------------------------------------------
-// Statistic Compound Component
-// ----------------------------------------------------------------------------
-
-type StatisticGroupComponent = React.FC<StatisticGroupProps>;
-
-interface StatisticComponent extends React.FC<StatisticProps> {
-    Group: StatisticGroupComponent;
-}
-
-const StatisticGroup: StatisticGroupComponent = (props) => {
-    const {i} = useContext(ThemeContext);
-    const style: CSSProperties = {...props.style, marginLeft: 0, marginRight: 0};
-    return <SStatisticGroup {...i} {...props} style={style}/>
-};
-
-const StatisticBase: React.FC<StatisticProps> = (props) => {
-    const {i, inverted} = useContext(ThemeContext);
-    const mergedProps = defaultGrey({...i, ...props}, !!inverted);
-    return <SStatistic {...mergedProps}/>
-};
-
-export const Statistic: StatisticComponent = Object.assign(StatisticBase, {
-    Group: StatisticGroup,
-});
-
-// ----------------------------------------------------------------------------
-// Breadcrumb Compound Component
-// ----------------------------------------------------------------------------
-
-interface BreadcrumbDividerProps {
-    icon?: string;
-}
-
-type BreadcrumbDividerComponent = React.FC<BreadcrumbDividerProps>;
-
-interface BreadcrumbComponent extends React.FC<BreadcrumbProps> {
-    Divider: BreadcrumbDividerComponent;
-}
-
-const BreadcrumbDivider: BreadcrumbDividerComponent = ({icon, ...props}) => {
-    const {inverted} = useContext(ThemeContext);
-
-    // TODO this only handles icons for now.
-    const className = `divider icon ${inverted} ${icon || ''}`;
-    return <i aria-hidden="true" className={className}></i>
-};
-
-const BreadcrumbBase: React.FC<BreadcrumbProps> = (props) => {
-    const {t} = useContext(ThemeContext);
-    return <SBreadcrumb {...props} {...t}/>
-};
-
-export const Breadcrumb: BreadcrumbComponent = Object.assign(BreadcrumbBase, {
-    Divider: BreadcrumbDivider,
-});
-
-// ----------------------------------------------------------------------------
-// Table Compound Component
-// ----------------------------------------------------------------------------
-
-type TableBodyComponent = React.FC<TableBodyProps>;
-type TableCellComponent = React.FC<TableCellProps>;
-type TableFooterComponent = React.FC<TableFooterProps>;
-type TableHeaderComponent = React.FC<TableHeaderProps>;
-type TableHeaderCellComponent = React.FC<TableHeaderCellProps>;
-type TableRowComponent = React.FC<TableRowProps>;
-
-interface TableComponent extends React.FC<TableProps> {
-    Body: TableBodyComponent;
-    Cell: TableCellComponent;
-    Footer: TableFooterComponent;
-    Header: TableHeaderComponent;
-    HeaderCell: TableHeaderCellComponent;
-    Row: TableRowComponent;
-}
-
-const TableBody: TableBodyComponent = (props) => {
-    return <STableBody {...props}/>
-};
-
-const TableCell: TableCellComponent = (props) => {
-    return <STableCell {...props}/>
-};
-
-const TableFooter: TableFooterComponent = (props) => {
-    return <STableFooter {...props}/>
-};
-
-const TableHeader: TableHeaderComponent = (props) => {
-    return <STableHeader {...props}/>
-};
-
-const TableHeaderCell: TableHeaderCellComponent = (props) => {
-    return <STableHeaderCell {...props}/>
-};
-
-const TableRow: TableRowComponent = (props) => {
-    return <STableRow {...props}/>
-};
-
-const TableBase: React.FC<TableProps> = (props) => {
-    const {i} = useContext(ThemeContext);
-    return <STable {...i} {...props}/>
-};
-
-export const Table: TableComponent = Object.assign(TableBase, {
-    Body: TableBody,
-    Cell: TableCell,
-    Footer: TableFooter,
-    Header: TableHeader,
-    HeaderCell: TableHeaderCell,
-    Row: TableRow,
-});
+/*
+ * The Semantic UI wrappers that used to live below this line are gone.
+ *
+ * They existed so call sites could get a themed Button, Segment, Modal and so on while
+ * the app still rendered Semantic components; every one of those call sites now imports
+ * from `src/components/ui` instead.  The dark-mode compatibility props they consumed --
+ * `i`, `s`, `t`, `inverted` -- went with them: those carried hardcoded greys, which is
+ * precisely what the token themes replaced.
+ *
+ * What remains is the part that was never about Semantic: the provider that resolves the
+ * chosen theme, stamps `data-theme` and `data-media-filter` on <html>, persists both, and
+ * hands Mantine our tokens.
+ */
diff --git a/app/src/components/ThemeSamplePage.js b/app/src/components/ThemeSamplePage.js
index 0777ae96..fc898fd9 100644
--- a/app/src/components/ThemeSamplePage.js
+++ b/app/src/components/ThemeSamplePage.js
@@ -382,20 +382,26 @@ export function ThemeSamplePage() {
         <Section label='Cards'>
             <CardGroup>
                 {[
-                    ['How To Sharpen An Axe The Right Way', 'Wranglerstar · 2024-11-03'],
-                    ['Pressure Canning Basics', 'RoseRed Homestead · 2025-02-17'],
-                    ['Solar Panel Wiring: Series vs Parallel', 'DIY Solar Power · 2025-08-21'],
-                    ['Ham Radio General License, Part 1', 'Ham Radio Crash Course · 2024-05-09'],
-                ].map(([title, meta]) => <Card
+                    ['How To Sharpen An Axe The Right Way', 'Wranglerstar · 2024-11-03', 'blue', 'film'],
+                    ['Pressure Canning Basics', 'RoseRed Homestead · 2025-02-17', 'blue', 'film'],
+                    ['Water Storage Guide.pdf', 'docs/ · 2025-08-21', 'red', 'file pdf'],
+                    ['Ham Radio General License.epub', 'ebooks/ · 2024-05-09', 'yellow', 'book'],
+                ].map(([title, meta, color, icon]) => <Card
                     key={title}
                     title={title}
                     meta={meta}
+                    color={color}
                     media={<div style={{
                         aspectRatio: '16/9', background: 'var(--head)', display: 'flex',
                         alignItems: 'center', justifyContent: 'center', color: 'var(--muted)',
-                    }}><Icon name='film' size={34}/></div>}
+                    }}><Icon name={icon} size={34}/></div>}
                 />)}
             </CardGroup>
+            <p style={{fontSize: 12, color: 'var(--muted)', marginTop: 10}}>
+                The bottom edge carries the file type's colour, so a grid of results is
+                scannable by kind before any title is read. It comes from a token, so night
+                and amber render the accent in their own single hue rather than four.
+            </p>
         </Section>
 
         <Section label='Loading placeholders'>
@@ -410,6 +416,9 @@ export function ThemeSamplePage() {
                 <Row>
                     <Button role='cancel' icon='eye' onClick={() => setModalOpen(true)}>Open a modal</Button>
                 </Row>
+                <div style={{marginTop: 12, maxWidth: 320}}>
+                    <Progress indeterminate label='Uploading…'/>
+                </div>
                 <p style={{fontSize: 12, color: 'var(--muted)', marginBottom: 0, marginTop: 10}}>
                     Semantic's compound shape is kept — Modal.Header, Modal.Content,
                     Modal.Actions — so the 34 call sites written against it migrate by import.
diff --git a/app/src/components/Upload.js b/app/src/components/Upload.js
index 2c12970c..ce59bc3c 100644
--- a/app/src/components/Upload.js
+++ b/app/src/components/Upload.js
@@ -1,16 +1,11 @@
 import React from "react";
 import {useDropzone} from "react-dropzone";
-import {Form, Header, Icon, Progress, Segment} from "./Theme";
-import {DirectorySearch, mimetypeIconName, Toggle} from "./Common";
+import {Box, Group, Header, Icon, Panel, Progress, Stack} from "./ui";
+import {DirectorySearch, mimetypeIconName, RequiredAsterisk, Toggle} from "./Common";
 import {useUploadFile} from "../hooks/customHooks";
 import _ from "lodash";
-import {ThemeContext} from "../contexts/contexts";
-import Grid from "semantic-ui-react/dist/commonjs/collections/Grid";
-import {Form as SForm} from "semantic-ui-react";
 
 export function Upload({disabled}) {
-    const {t} = React.useContext(ThemeContext);
-
     const {
         setFiles,
         progresses,
@@ -57,33 +52,29 @@ export function Upload({disabled}) {
                 color = 'orange';
                 statusString = 'Already Exists:';
             }
-            // Only indicating when upload is pending.
-            let indicating = status === 'pending';
 
-            return <Grid.Row key={name}>
-                <Grid.Column mobile={3} tablet={2} computer={1}>
-                    <Icon name={mimetypeIconName(type, name.toLowerCase())} size='big'/>
-                </Grid.Column>
-                <Grid.Column mobile={13} tablet={14} computer={15}>
-                    <Progress progress indicating={indicating} percent={percent} color={color}>
-                        <p {...t}>{statusString} {name}</p>
-                    </Progress>
-                </Grid.Column>
-            </Grid.Row>
+            return <Group key={name} align='center' wrap='nowrap' gap='sm'>
+                <Icon name={mimetypeIconName(type, name.toLowerCase())} size='large'/>
+                <Box style={{flex: 1}}>
+                    <Progress percent={percent} color={color} label={`${statusString} ${name}`}/>
+                </Box>
+            </Group>
         })
     }
 
     return <>
-        <Form>
-            <SForm.Field required>
-                <label>Destination</label>
+        <Stack gap='sm'>
+            <div>
+                <label style={{display: 'block', marginBottom: 4}}>
+                    <b>Destination</b> <RequiredAsterisk/>
+                </label>
                 <DirectorySearch
                     onSelect={i => setDestination(i)}
                     disabled={disabled || inProgress}
                     style={{marginBottom: '0.5em'}}
                 />
                 {tagsSelector}
-            </SForm.Field>
+            </div>
 
             <Toggle
                 checked={overwrite}
@@ -91,50 +82,30 @@ export function Upload({disabled}) {
                 onChange={() => setOverwrite(!overwrite)}
                 disabled={disabled || inProgress}
             />
-        </Form>
+        </Stack>
 
         {destination ?
-            <Segment>
-                <Grid columns={1}>
-                    <Grid.Row>
-                        <Grid.Column style={{padding: '1em'}}>
-                            <Form>
-                                <div {...getRootProps()}>
-                                    <input {...getInputProps()}/>
-                                    <Grid textAlign='center'>
-                                        <Grid.Row>
-                                            <Grid.Column>
-                                                <Header icon>
-                                                    <Icon name='file text'/>
-                                                    Click here, or drop files here to upload
-                                                </Header>
-                                            </Grid.Column>
-                                        </Grid.Row>
-                                    </Grid>
-                                </div>
-                            </Form>
-                        </Grid.Column>
-                    </Grid.Row>
-                </Grid>
-            </Segment>
+            <Panel style={{marginTop: '1em'}}>
+                <div {...getRootProps()} style={{padding: '1em', textAlign: 'center', cursor: 'pointer'}}>
+                    <input {...getInputProps()}/>
+                    <Header as='h3' icon='file text'>
+                        Click here, or drop files here to upload
+                    </Header>
+                </div>
+            </Panel>
             : <Header as='h3'>You must search for a directory to place your files</Header>
         }
 
         <br/>
 
-        <Grid>
-            <Grid.Row columns={1}>
-                <Grid.Column>
-                    {progresses && Object.keys(progresses).length > 1 && <Progress progress
-                                                                                   percent={overallProgress}
-                                                                                   color='blue'
-                                                                                   label='Overall Progress'
-                    />}
-                </Grid.Column>
-            </Grid.Row>
-        </Grid>
-        <Grid columns={2}>
+        {progresses && Object.keys(progresses).length > 1 && <Progress
+            percent={overallProgress}
+            color='blue'
+            label='Overall Progress'
+        />}
+
+        <Stack gap='sm' mt='sm'>
             {progressBars}
-        </Grid>
+        </Stack>
     </>
 }
diff --git a/app/src/components/VideoPlayer.js b/app/src/components/VideoPlayer.js
index c0604528..0e88cdc9 100644
--- a/app/src/components/VideoPlayer.js
+++ b/app/src/components/VideoPlayer.js
@@ -1,4 +1,4 @@
-import React, {useContext, useEffect, useState} from 'react';
+import React, {useEffect, useState} from 'react';
 import {useHotkeys} from 'react-hotkeys-hook';
 import {deleteFileGroups, downloadVideoMetadata, tagFileGroup, untagFileGroup} from "../api";
 import {Link, useNavigate, useParams} from "react-router";
@@ -17,17 +17,14 @@ import {
     useMediaSession,
     useTitle
 } from "./Common";
-import Grid from "semantic-ui-react/dist/commonjs/collections/Grid";
-import Container from "semantic-ui-react/dist/commonjs/elements/Container";
 import {VideoPlaceholder} from "./Placeholder";
 import {useChannel, useVideoCaptions, useVideoExtras} from "../hooks/customHooks";
-import {ThemeContext} from "../contexts/contexts";
-import {Button, darkTheme, Header, Icon, Loader, Segment, Tab} from "./Theme";
+import {Button, Grid, Header, Icon, Label, Loading, Panel, Tabs, TextInput} from "./ui";
 import {VideoCard} from "./Videos";
 import {TagsSelector} from "../Tags";
 import {AddToPlaylistButton} from "./AddToPlaylist";
-import {Comment, CommentGroup, Input, Label, Transition} from "semantic-ui-react";
 import {TaggedDeleteConfirmModal} from "./TaggedDeleteConfirmModal";
+import {IconPlayerPause, IconPlayerPlay} from "@tabler/icons-react";
 
 const MEDIA_PATH = '/media';
 
@@ -117,7 +114,7 @@ const NoComments = ({video}) => {
             <p>No comments have been been downloaded. Refresh the video?</p>
 
             <APIButton
-                color='blue'
+                role='primary'
                 size='large'
                 onClick={handleRefresh}
             >Refresh</APIButton>
@@ -132,43 +129,43 @@ const NoComments = ({video}) => {
     }
 }
 
+// Semantic's <Comment>/<CommentGroup> have no equivalent in the token library -- this is a nested
+// comment thread, not a reusable widget, so it is built here from plain elements and tokens.
 const VideoComment = ({comment, children}) => {
-    const {t} = React.useContext(ThemeContext);
-
     const {is_favorited, like_count, author, timestamp, text, author_is_uploader} = comment;
 
     // Author comments and favorited comments are important.
     let specialIcon = null;
     if (author_is_uploader) {
-        specialIcon = <Icon name='star' color='green'/>;
+        specialIcon = <Icon name='star' label='Uploader' style={{color: 'var(--green)'}}/>;
     } else if (is_favorited) {
-        specialIcon = <Icon name='heart' color='red'/>;
+        specialIcon = <Icon name='heart' label='Favorited' style={{color: 'var(--red)'}}/>;
     }
 
-    const dateElm = <div {...t}>{isoDatetimeToAgoPopup(timestamp * 1000)}</div>;
-    const likesElm = like_count && <div {...t}>
-        <Icon name='thumbs up'/>{humanNumber(comment['like_count'])}
-    </div>;
-
-    return <Comment>
-        <Comment.Content>
-            <Comment.Author as='a'>
-                <span {...t}>{specialIcon}{author}</span>
-            </Comment.Author>
-            <Comment.Metadata>
-                {dateElm}
-                {likesElm}
-            </Comment.Metadata>
-            <Comment.Text {...t}>
-                <MultilineText text={text} style={{marginLeft: '0.5em'}}/>
-            </Comment.Text>
-        </Comment.Content>
+    return <div style={{marginBottom: '1.2em'}}>
+        <div style={{fontWeight: 600, display: 'flex', alignItems: 'center', gap: '0.3em'}}>
+            {specialIcon}<span>{author}</span>
+        </div>
+        <div style={{display: 'flex', gap: '1em', fontSize: '0.85em', color: 'var(--muted)'}}>
+            <div>{isoDatetimeToAgoPopup(timestamp * 1000)}</div>
+            {like_count ? <div>
+                <Icon name='thumbs up' size={14}/> {humanNumber(comment['like_count'])}
+            </div> : null}
+        </div>
+        <div>
+            <MultilineText text={text} style={{marginLeft: '0.5em'}}/>
+        </div>
         {children && !_.isEmpty(children) &&
-            <CommentGroup>
+            <div style={{
+                marginLeft: '1.5em',
+                marginTop: '0.7em',
+                paddingLeft: '1em',
+                borderLeft: '1px solid var(--border)',
+            }}>
                 {children.map((i, key) => <VideoComment key={key} comment={i}/>)}
-            </CommentGroup>
+            </div>
         }
-    </Comment>
+    </div>
 }
 
 
@@ -202,9 +199,9 @@ const Comments = ({comments, video}) => {
         groupedByParent[obj.parent] = _.sortBy(children, ['timestamp']);
     })
 
-    return <CommentGroup>
+    return <div>
         {rootComments.map((i, key) => <VideoComment key={key} comment={i} children={groupedByParent[i.id]}/>)}
-    </CommentGroup>
+    </div>
 }
 
 // Generate a video page URL for a file object.
@@ -214,11 +211,10 @@ function getVideoLink(file) {
 }
 
 function VideoPage({videoFile, prevFile, nextFile, fetchVideo, ...props}) {
-    const {theme} = useContext(ThemeContext);
-
     const navigate = useNavigate();
     const videoRef = React.useRef();
     const [taggedFileGroups, setTaggedFileGroups] = useState(null);
+    const [activeTab, setActiveTab] = useState('comments');
 
     useTitle(videoFile ? videoFile.title ? videoFile.title : videoFile.name : null);
     let video;
@@ -353,26 +349,9 @@ function VideoPage({videoFile, prevFile, nextFile, fetchVideo, ...props}) {
         description = formatVideoDescription(description, setVideoTime)
     }
 
-    const descriptionPane = {
-        menuItem: 'Description', render: () => <Tab.Pane>
-            <pre className="wrap-text">
-                {description}
-            </pre>
-        </Tab.Pane>
-    };
-
-    const captionsPane = {
-        menuItem: 'Captions', render: () => <CaptionsPane
-            captions={captions}
-            captionsLoading={captionsLoading}
-            fetchCaptions={fetchCaptions}
-            setVideoTime={setVideoTime}
-        />
-    };
-
     const getFile = (suffix) => videoFile.files.find(i => i.path.toLowerCase().endsWith(suffix));
     const fileSize = (file) => file && file.size
-        ? <span style={{marginLeft: '1em', color: 'grey'}}>({humanFileSize(file.size)})</span>
+        ? <span style={{marginLeft: '1em', color: 'var(--muted)'}}>({humanFileSize(file.size)})</span>
         : null;
 
     const {poster_file, info_json_file} = video;
@@ -380,120 +359,6 @@ function VideoPage({videoFile, prevFile, nextFile, fetchVideo, ...props}) {
     const ffprobeJsonFile = getFile('.ffprobe.json');
     const tableStyle = {width: '100%', borderCollapse: 'separate', borderSpacing: '0 0.7em'};
     const labelStyle = {whiteSpace: 'nowrap', paddingRight: '1.5em', verticalAlign: 'top'};
-    const filesPane = {
-        menuItem: 'Files', render: () => <Tab.Pane>
-            <table style={tableStyle}>
-                <tbody>
-                <tr>
-                    <td style={labelStyle}><strong>{isAudio ? 'Audio File' : 'Video File'}</strong></td>
-                    <td>
-                        {video['video_path']
-                            ? <><PreviewPath path={video['video_path']} mimetype={isAudio ? 'audio/*' : 'video/*'} taggable={false}>
-                                {video['video_path']}
-                            </PreviewPath>{fileSize(videoPathFile)}</>
-                            : 'Unknown'}
-                    </td>
-                </tr>
-
-                <tr>
-                    <td style={labelStyle}><strong>Caption Files</strong></td>
-                    <td>
-                        {caption_files
-                            ? caption_files.map(i => <div key={i['path']} style={{marginBottom: '0.3em'}}>
-                                <PreviewPath {...i} taggable={false}>{i['path']}</PreviewPath>
-                                {fileSize(i)}
-                            </div>)
-                            : 'No caption files'}
-                    </td>
-                </tr>
-
-                <tr>
-                    <td style={labelStyle}><strong>Poster File</strong></td>
-                    <td>
-                        {poster_file
-                            ? <><PreviewPath path={poster_file['path']} mimetype={poster_file['mimetype']}
-                                             taggable={false}>
-                                {poster_file['path']}
-                            </PreviewPath>{fileSize(poster_file)}</>
-                            : 'No poster file'}
-                    </td>
-                </tr>
-
-                <tr>
-                    <td style={labelStyle}><strong>Info JSON File</strong></td>
-                    <td>
-                        {info_json_file
-                            ? <><PreviewPath path={info_json_file['path']} mimetype={info_json_file['mimetype']}
-                                             taggable={false}>
-                                {info_json_file['path']}
-                            </PreviewPath>{fileSize(info_json_file)}</>
-                            : 'No yt-dlp info json file'}
-                    </td>
-                </tr>
-
-                <tr>
-                    <td style={labelStyle}><strong>ffprobe JSON File</strong></td>
-                    <td>
-                        {ffprobeJsonFile
-                            ? <><PreviewPath path={ffprobeJsonFile['path']} mimetype={ffprobeJsonFile['mimetype']}
-                                             taggable={false}>
-                                {ffprobeJsonFile['path']}
-                            </PreviewPath>{fileSize(ffprobeJsonFile)}</>
-                            : 'No ffprobe json file'}
-                    </td>
-                </tr>
-
-                <tr>
-                    <td style={labelStyle}><strong>Directory</strong></td>
-                    <td><DirectoryLink path={videoFile['directory']}/></td>
-                </tr>
-                </tbody>
-            </table>
-        </Tab.Pane>
-    }
-
-    const commentsPane = {
-        menuItem: 'Comments', render: () => <Tab.Pane>
-            <Header as='h3'>Top Comments</Header>
-            <Comments comments={comments} video={videoFile}/>
-        </Tab.Pane>,
-    };
-
-    const tabPanes = [commentsPane, descriptionPane, filesPane, captionsPane];
-    const tabMenu = theme === darkTheme ? {inverted: true, attached: true} : {attached: true};
-
-    const aboutSegment = <Segment>
-        <Header as='h2'>About Video</Header>
-
-        <Grid columns={2}>
-            <Grid.Row>
-                <Grid.Column>
-                    <h3>Size</h3>
-                    <p>{videoFile.size ? humanFileSize(videoFile.size) : 'Unknown'}</p>
-                </Grid.Column>
-                <Grid.Column>
-                    <h3>View Count</h3>
-                    <p>{video.view_count ? humanNumber(video.view_count) : 'N/A'}</p>
-                </Grid.Column>
-            </Grid.Row>
-            <Grid.Row>
-                <Grid.Column>
-                    <h3>Codec Names</h3>
-                    <>{video.codec_names ? video.codec_names.map(i => <Label key={i}>{i}</Label>) : 'N/A'}</>
-                </Grid.Column>
-                <Grid.Column>
-                    <h3>Censored</h3>
-                    <p>{videoFile.censored ? 'Yes' : 'No'}</p>
-                </Grid.Column>
-            </Grid.Row>
-            <Grid.Row columns={1}>
-                <Grid.Column>
-                    <h3>Source URL</h3>
-                    <p>{videoFile.url ? <a href={videoFile.url}>{videoFile.url}</a> : 'N/A'}</p>
-                </Grid.Column>
-            </Grid.Row>
-        </Grid>
-    </Segment>;
 
     const localAddTag = async (name) => {
         await tagFileGroup(videoFile, name);
@@ -508,20 +373,18 @@ function VideoPage({videoFile, prevFile, nextFile, fetchVideo, ...props}) {
     let videoSource = <source src={videoUrl}/>;
     const isAudio = videoFile.mimetype && videoFile.mimetype.startsWith('audio/');
 
-    let prevNextVideosSegment = <Segment><p>No related videos found.</p></Segment>;
+    let prevNextVideosPanel = <Panel><p>No related videos found.</p></Panel>;
     if (prevFile || nextFile) {
-        prevNextVideosSegment = <Segment>
-            <Grid columns={2} stackable>
-                <Grid.Row>
-                    <Grid.Column textAlign='left'>
-                        {prevFile && <><Header as='h3'>Older</Header><VideoCard file={prevFile}/></>}
-                    </Grid.Column>
-                    <Grid.Column textAlign='left'>
-                        {nextFile && <><Header as='h3'>Newer</Header><VideoCard file={nextFile}/></>}
-                    </Grid.Column>
-                </Grid.Row>
+        prevNextVideosPanel = <Panel>
+            <Grid>
+                <Grid.Col span={{base: 12, sm: 6}}>
+                    {prevFile && <><Header as='h3'>Older</Header><VideoCard file={prevFile}/></>}
+                </Grid.Col>
+                <Grid.Col span={{base: 12, sm: 6}}>
+                    {nextFile && <><Header as='h3'>Newer</Header><VideoCard file={nextFile}/></>}
+                </Grid.Col>
             </Grid>
-        </Segment>
+        </Panel>
     }
 
     let title = video.video_path;
@@ -531,19 +394,35 @@ function VideoPage({videoFile, prevFile, nextFile, fetchVideo, ...props}) {
         title = videoFile.stem;
     }
 
+    const audioPlayPauseLabel = audioPlaying ? 'Pause' : 'Play';
+
     return <>
-        <Container style={{margin: '1em'}}>
+        <div style={{margin: '1em'}}>
             <BackButton/>
-        </Container>
+        </div>
 
         {isAudio ? <>
             {posterUrl && <div
-                className='audio-poster-container'
+                // A wrapper whose custom play/pause/volume glyphs are drawn over the poster image: the whole
+                // composite must be tinted as one unit in night mode, so it carries `.media` even though the
+                // <img/> inside is already a filtered leaf on its own.
+                className='audio-poster-container media'
+                role='button'
+                tabIndex={0}
+                aria-label={audioPlaying ? 'Pause audio' : 'Play audio'}
                 onClick={() => {
                     if (videoRef.current) {
                         videoRef.current.paused ? videoRef.current.play() : videoRef.current.pause();
                     }
                 }}
+                onKeyDown={(e) => {
+                    if (e.key === 'Enter' || e.key === ' ') {
+                        e.preventDefault();
+                        if (videoRef.current) {
+                            videoRef.current.paused ? videoRef.current.play() : videoRef.current.pause();
+                        }
+                    }
+                }}
                 onMouseEnter={() => setAudioPosterHover(true)}
                 onMouseLeave={() => setAudioPosterHover(false)}
             >
@@ -552,16 +431,24 @@ function VideoPage({videoFile, prevFile, nextFile, fetchVideo, ...props}) {
                     alt={mediaTitle || 'Audio thumbnail'}
                     style={{maxWidth: '100%', maxHeight: '400px', cursor: 'pointer'}}
                 />
-                <Transition visible={showAudioOverlay} animation='fade' duration={500}>
-                    <div className='audio-poster-overlay'>
-                        <Icon name='volume up' size='massive'/>
-                    </div>
-                </Transition>
-                <Transition visible={audioPosterHover && !showAudioOverlay} animation='fade' duration={200}>
-                    <div className='audio-poster-overlay'>
-                        <Icon name={audioPlaying ? 'pause circle outline' : 'play circle outline'} size='massive'/>
-                    </div>
-                </Transition>
+                <div
+                    className='audio-poster-overlay'
+                    aria-hidden='true'
+                    style={{opacity: showAudioOverlay ? 1 : 0, transition: 'opacity 500ms ease'}}
+                >
+                    <Icon name='volume up' size={64}/>
+                </div>
+                <div
+                    className='audio-poster-overlay'
+                    aria-hidden='true'
+                    style={{
+                        opacity: (audioPosterHover && !showAudioOverlay) ? 1 : 0,
+                        transition: 'opacity 200ms ease',
+                    }}
+                >
+                    <Icon component={audioPlaying ? IconPlayerPause : IconPlayerPlay} size={64}
+                          label={audioPlayPauseLabel}/>
+                </div>
             </div>}
             <audio controls
                    autoPlay={props.autoplay !== undefined ? props.autoplay : true}
@@ -585,8 +472,8 @@ function VideoPage({videoFile, prevFile, nextFile, fetchVideo, ...props}) {
             {captionUrls.map(i => <CaptionTrack key={i} src={i}/>)}
         </video>}
 
-        <Container style={{marginTop: '1em'}}>
-            <Segment>
+        <div style={{marginTop: '1em'}}>
+            <Panel>
 
                 <Header as='h2'>{title}</Header>
                 {videoFile.published_datetime && <h3>{isoDatetimeToAgoPopup(videoFile.published_datetime)}</h3>}
@@ -597,37 +484,158 @@ function VideoPage({videoFile, prevFile, nextFile, fetchVideo, ...props}) {
                 </h3>
 
                 <p>
-                    <Button as='a' href={downloadUrl}>
-                        <Icon name='download'/>
+                    <Button component='a' href={downloadUrl} icon='download'>
                         Download
                     </Button>
                     <APIButton
-                        color='red'
+                        role='danger'
                         confirmContent='Are you sure you want to delete this video?  All files related to this video will be deleted. It will not be downloaded again!'
                         confirmButton='Delete'
                         onClick={async () => await handleDeleteVideo(videoFile.id)}
                         obeyWROLMode={true}
                     >Delete</APIButton>
                     <APIButton
-                        color='blue'
+                        role='primary'
                         onClick={handleRefresh}
                         obeyWROLMode={true}
                         disabled={!videoFile.url}
                     >Refresh</APIButton>
                     <AddToPlaylistButton fileGroupId={videoFile.id}/>
                 </p>
-            </Segment>
+            </Panel>
 
-            <Segment>
+            <Panel>
                 <TagsSelector selectedTagNames={videoFile['tags']} onAdd={localAddTag} onRemove={localRemoveTag}/>
-            </Segment>
+            </Panel>
 
-            {aboutSegment}
+            <Panel>
+                <Header as='h2'>About Video</Header>
 
-            <Tab menu={tabMenu} panes={tabPanes}/>
+                <Grid>
+                    <Grid.Col span={6}>
+                        <h3>Size</h3>
+                        <p>{videoFile.size ? humanFileSize(videoFile.size) : 'Unknown'}</p>
+                    </Grid.Col>
+                    <Grid.Col span={6}>
+                        <h3>View Count</h3>
+                        <p>{video.view_count ? humanNumber(video.view_count) : 'N/A'}</p>
+                    </Grid.Col>
+                    <Grid.Col span={6}>
+                        <h3>Codec Names</h3>
+                        <>{video.codec_names ? video.codec_names.map(i => <Label key={i}>{i}</Label>) : 'N/A'}</>
+                    </Grid.Col>
+                    <Grid.Col span={6}>
+                        <h3>Censored</h3>
+                        <p>{videoFile.censored ? 'Yes' : 'No'}</p>
+                    </Grid.Col>
+                    <Grid.Col span={12}>
+                        <h3>Source URL</h3>
+                        <p>{videoFile.url ? <a href={videoFile.url}>{videoFile.url}</a> : 'N/A'}</p>
+                    </Grid.Col>
+                </Grid>
+            </Panel>
 
-            {prevNextVideosSegment}
-        </Container>
+            <Tabs value={activeTab} onChange={setActiveTab} keepMounted={false}>
+                <Tabs.List>
+                    <Tabs.Tab value='comments'>Comments</Tabs.Tab>
+                    <Tabs.Tab value='description'>Description</Tabs.Tab>
+                    <Tabs.Tab value='files'>Files</Tabs.Tab>
+                    <Tabs.Tab value='captions'>Captions</Tabs.Tab>
+                </Tabs.List>
+
+                <Tabs.Panel value='comments' style={{paddingTop: '1em'}}>
+                    <Header as='h3'>Top Comments</Header>
+                    <Comments comments={comments} video={videoFile}/>
+                </Tabs.Panel>
+
+                <Tabs.Panel value='description' style={{paddingTop: '1em'}}>
+                    <pre className="wrap-text">
+                        {description}
+                    </pre>
+                </Tabs.Panel>
+
+                <Tabs.Panel value='files' style={{paddingTop: '1em'}}>
+                    <table style={tableStyle}>
+                        <tbody>
+                        <tr>
+                            <td style={labelStyle}><strong>{isAudio ? 'Audio File' : 'Video File'}</strong></td>
+                            <td>
+                                {video['video_path']
+                                    ? <><PreviewPath path={video['video_path']} mimetype={isAudio ? 'audio/*' : 'video/*'} taggable={false}>
+                                        {video['video_path']}
+                                    </PreviewPath>{fileSize(videoPathFile)}</>
+                                    : 'Unknown'}
+                            </td>
+                        </tr>
+
+                        <tr>
+                            <td style={labelStyle}><strong>Caption Files</strong></td>
+                            <td>
+                                {caption_files
+                                    ? caption_files.map(i => <div key={i['path']} style={{marginBottom: '0.3em'}}>
+                                        <PreviewPath {...i} taggable={false}>{i['path']}</PreviewPath>
+                                        {fileSize(i)}
+                                    </div>)
+                                    : 'No caption files'}
+                            </td>
+                        </tr>
+
+                        <tr>
+                            <td style={labelStyle}><strong>Poster File</strong></td>
+                            <td>
+                                {poster_file
+                                    ? <><PreviewPath path={poster_file['path']} mimetype={poster_file['mimetype']}
+                                                     taggable={false}>
+                                        {poster_file['path']}
+                                    </PreviewPath>{fileSize(poster_file)}</>
+                                    : 'No poster file'}
+                            </td>
+                        </tr>
+
+                        <tr>
+                            <td style={labelStyle}><strong>Info JSON File</strong></td>
+                            <td>
+                                {info_json_file
+                                    ? <><PreviewPath path={info_json_file['path']} mimetype={info_json_file['mimetype']}
+                                                     taggable={false}>
+                                        {info_json_file['path']}
+                                    </PreviewPath>{fileSize(info_json_file)}</>
+                                    : 'No yt-dlp info json file'}
+                            </td>
+                        </tr>
+
+                        <tr>
+                            <td style={labelStyle}><strong>ffprobe JSON File</strong></td>
+                            <td>
+                                {ffprobeJsonFile
+                                    ? <><PreviewPath path={ffprobeJsonFile['path']} mimetype={ffprobeJsonFile['mimetype']}
+                                                     taggable={false}>
+                                        {ffprobeJsonFile['path']}
+                                    </PreviewPath>{fileSize(ffprobeJsonFile)}</>
+                                    : 'No ffprobe json file'}
+                            </td>
+                        </tr>
+
+                        <tr>
+                            <td style={labelStyle}><strong>Directory</strong></td>
+                            <td><DirectoryLink path={videoFile['directory']}/></td>
+                        </tr>
+                        </tbody>
+                    </table>
+                </Tabs.Panel>
+
+                <Tabs.Panel value='captions' style={{paddingTop: '1em'}}>
+                    <CaptionsPane
+                        captions={captions}
+                        captionsLoading={captionsLoading}
+                        fetchCaptions={fetchCaptions}
+                        setVideoTime={setVideoTime}
+                    />
+                </Tabs.Panel>
+            </Tabs>
+
+            {prevNextVideosPanel}
+        </div>
         <TaggedDeleteConfirmModal
             open={taggedFileGroups !== null}
             taggedFileGroups={taggedFileGroups}
@@ -661,11 +669,11 @@ function CaptionsPane({captions, captionsLoading, fetchCaptions, setVideoTime})
     }, []);
 
     if (captionsLoading) {
-        return <Tab.Pane><Loader active/></Tab.Pane>;
+        return <Loading/>;
     }
 
     if (!captions || captions.length === 0) {
-        return <Tab.Pane>No captions available.</Tab.Pane>;
+        return <div>No captions available.</div>;
     }
 
     let filtered = captions;
@@ -677,14 +685,13 @@ function CaptionsPane({captions, captionsLoading, fetchCaptions, setVideoTime})
         });
     }
 
-    return <Tab.Pane>
-        <Input
-            fluid
-            icon='filter'
+    return <>
+        <TextInput
+            leftSection={<Icon name='filter' size={14}/>}
             placeholder='Filter captions...'
             value={filter}
-            onChange={(e, {value}) => setFilter(value)}
-            style={{marginBottom: '1em'}}
+            onChange={(e) => setFilter(e.currentTarget.value)}
+            style={{marginBottom: '1em', width: '100%'}}
         />
         <div style={{maxHeight: '400px', overflowY: 'auto'}}>
             {filtered.map((chunk, idx) => (
@@ -694,7 +701,7 @@ function CaptionsPane({captions, captionsLoading, fetchCaptions, setVideoTime})
                            e.preventDefault();
                            setVideoTime(chunk.start_seconds);
                        }}
-                       style={{whiteSpace: 'nowrap', fontFamily: 'monospace'}}
+                       style={{whiteSpace: 'nowrap', fontFamily: 'var(--font-mono)'}}
                     >
                         {formatCaptionTimestamp(chunk.start_seconds)}
                     </a>
@@ -702,7 +709,7 @@ function CaptionsPane({captions, captionsLoading, fetchCaptions, setVideoTime})
                 </div>
             ))}
         </div>
-    </Tab.Pane>;
+    </>;
 }
 
 export default VideoPage;
diff --git a/app/src/components/Videos.js b/app/src/components/Videos.js
index da5b109c..d9fa7592 100644
--- a/app/src/components/Videos.js
+++ b/app/src/components/Videos.js
@@ -15,6 +15,7 @@ import {
     HelpHeader,
     InfoHeader,
     isoDatetimeToAgoPopup,
+    mimetypeColor,
     PageContainer,
     PreviewLink,
     scrollToTop,
@@ -880,7 +881,8 @@ export function VideoCard({file}) {
         <div>{detailLine}</div>
     </>;
 
-    return <Card media={media} title={titleElm} meta={meta}/>
+    return <Card media={media} title={titleElm} meta={meta}
+                 color={mimetypeColor(file.mimetype, file.primary_path)}/>
 }
 
 export function VideoRowCells({file}) {
diff --git a/app/src/components/Zim.js b/app/src/components/Zim.js
index 1cc2fb0e..b7e18f7a 100644
--- a/app/src/components/Zim.js
+++ b/app/src/components/Zim.js
@@ -1,31 +1,5 @@
 import {useOutdatedZims, useSearchZim, useWROLMode} from "../hooks/customHooks";
-import {
-    Accordion,
-    Button,
-    Divider,
-    Header,
-    Icon,
-    Loader,
-    Modal,
-    Placeholder,
-    Segment
-} from "./Theme";
-import {HeadlineText} from "./Headline";
-import {TextPlaceholder} from "./Placeholder";
-import {
-    AccordionContent,
-    AccordionTitle,
-    Button as SButton,
-    Dropdown,
-    Icon as SIcon,
-    Label,
-    Message,
-    PlaceholderHeader,
-    PlaceholderLine,
-    TableCell,
-    TableRow
-} from "semantic-ui-react";
-import React, {useContext, useState} from "react";
+import React, {useState} from "react";
 import {
     APIButton,
     encodeMediaPath,
@@ -43,7 +17,23 @@ import {
     useTitle,
     WarningMessage
 } from "./Common";
-import Grid from "semantic-ui-react/dist/commonjs/collections/Grid";
+import {
+    Accordion,
+    Button,
+    Divider,
+    Group,
+    Header,
+    Label,
+    Loading,
+    Message,
+    Modal,
+    Panel,
+    Placeholder,
+    Select,
+    Table,
+    toast,
+} from "./ui";
+import {TextPlaceholder} from "./Placeholder";
 import {TagsSelector} from "../Tags";
 import {AddToPlaylistButton} from "./AddToPlaylist";
 import {
@@ -60,19 +50,17 @@ import {
 } from "../api";
 import {useSearch} from "./Search";
 import {TagsQuerySelector} from "./Files";
-import {ThemeContext} from "../contexts/contexts";
 import {Link, Route, Routes} from "react-router";
 import {SortableTable} from "./SortableTable";
-import {toast} from "./ui";
 import _ from "lodash";
 import {ZIM_VIEWER_URI} from "./Vars";
+import {HeadlineText} from "./Headline";
 
 export const OutdatedZimsMessage = ({onClick}) => {
     const [open, setOpen] = React.useState(false);
 
     const {outdated, current} = useOutdatedZims();
 
-    const onOpen = () => setOpen(true);
     const onClose = () => setOpen(false);
 
     const handleDelete = async () => {
@@ -106,9 +94,7 @@ export const OutdatedZimsMessage = ({onClick}) => {
         }
     }
 
-    let modalContent = <Placeholder>
-        <PlaceholderLine/>
-    </Placeholder>;
+    let modalContent = <Placeholder lines={1}/>;
     if (outdated && outdated.length > 0) {
         modalContent = <>
             <Header as='h3'>To Delete</Header>
@@ -119,38 +105,29 @@ export const OutdatedZimsMessage = ({onClick}) => {
         </>
     }
 
-    return <Message icon info>
-        <SIcon name='question'/>
-        <Message.Content>
-            <Message.Header>Outdated Zim Files</Message.Header>
-            New Zim files have been downloaded. Outdated Zim files can be removed.
-            <p></p>
+    return <Message kind='info' icon='question' title='Outdated Zim Files'>
+        New Zim files have been downloaded. Outdated Zim files can be removed.
+        <p></p>
 
-            <SButton primary onClick={() => setOpen(true)}>Delete</SButton>
-            <Modal closeIcon
-                   open={open}
-                   onClose={onClose}
-                   onOpen={onOpen}
-            >
-                <Modal.Header>Delete</Modal.Header>
-                <Modal.Content>
-                    {modalContent}
-                </Modal.Content>
-                <Modal.Actions>
-                    <APIButton
-                        color='red'
-                        floated='left'
-                        onClick={handleDelete}
-                    >Delete</APIButton>
-                    <Button onClick={onClose}>Close</Button>
-                </Modal.Actions>
-            </Modal>
+        <Button role='danger' onClick={() => setOpen(true)}>Delete</Button>
+        <Modal open={open}
+               onClose={onClose}
+               title='Delete'
+        >
+            {modalContent}
+            <Modal.Actions>
+                <APIButton
+                    role='danger'
+                    onClick={handleDelete}
+                >Delete</APIButton>
+                <Button role='cancel' onClick={onClose}>Close</Button>
+            </Modal.Actions>
+        </Modal>
 
-            <Link to='/files?folders=zims'><SButton>Delete Manually</SButton></Link>
-            <APIButton secondary
-                       onClick={handleIgnore}
-            >Ignore Forever</APIButton>
-        </Message.Content>
+        <Link to='/files?folders=zims'><Button role='cancel'>Delete Manually</Button></Link>
+        <APIButton role='cancel'
+                   onClick={handleIgnore}
+        >Ignore Forever</APIButton>
     </Message>
 }
 
@@ -188,42 +165,38 @@ const ZimSearchEntry = ({zimId, onTag, onUntag, entry}) => {
             {tagIcon}
         </Header>
         <HeadlineText headline={headline}/>
-        <Modal closeIcon
-               open={open}
+        <Modal open={open}
                onClose={() => setOpen(false)}>
-            <Modal.Content>
-                <div className='preview-fit'>
-                    <ZimViewer src={url} style={{
-                        // Override IframeViewer's `fixed` so the iframe stays inside the Modal.
-                        position: 'static',
-                        height: '100%', width: '100%', border: 'none',
-                        // Use white to avoid iframe displaying with dark-theme.
-                        backgroundColor: '#ffffff',
-                    }}/>
-                </div>
-            </Modal.Content>
+            <div className='preview-fit'>
+                <ZimViewer src={url} style={{
+                    // Override IframeViewer's `fixed` so the iframe stays inside the Modal.
+                    position: 'static',
+                    height: '100%', width: '100%', border: 'none',
+                    // Use white to avoid iframe displaying with dark-theme.
+                    backgroundColor: '#ffffff',
+                }}/>
+            </div>
             <Modal.Actions>
-                <Grid>
-                    <Grid.Column mobile={10} tablet={12}>
-                        <TagsSelector selectedTagNames={tag_names} onAdd={localAddTag} onRemove={localUntag}/>
-                    </Grid.Column>
-                    <Grid.Column width={4} textAlign='right'>
+                <Group justify='space-between' align='flex-start' wrap='wrap' style={{width: '100%'}}>
+                    <TagsSelector selectedTagNames={tag_names} onAdd={localAddTag} onRemove={localUntag}/>
+                    <Group gap='xs'>
                         <AddToPlaylistButton
                             zim={{zimId, entry: path, title: (title || path).replace(/<[^>]*>/g, '')}}
                             content={null} title='Add to Playlist'/>
-                        <Button color='blue' as='a' href={url} target='_blank' rel='noopener noreferrer'>Open</Button>
-                    </Grid.Column>
-                </Grid>
+                        <Button role='primary' component='a' href={url} target='_blank' rel='noopener noreferrer'>
+                            Open
+                        </Button>
+                    </Group>
+                </Group>
             </Modal.Actions>
         </Modal>
     </div>
 }
 
-const ZimAccordion = ({data, index, activeIndex, onClick, searchStr, activeTags}) => {
+const ZimAccordionItem = ({value, active, data, searchStr, activeTags}) => {
     const {id, estimate, metadata} = data;
     const {title, date} = metadata;
-    const {zim, fetchSearch, pages, loading} = useSearchZim(searchStr, id, index === activeIndex, activeTags);
-    const {t} = useContext(ThemeContext);
+    const {zim, fetchSearch, pages, loading} = useSearchZim(searchStr, id, active, activeTags);
 
     const localAddTag = async (zimId, path, name) => {
         await tagZimEntry(zimId, path, name);
@@ -239,11 +212,14 @@ const ZimAccordion = ({data, index, activeIndex, onClick, searchStr, activeTags}
     if (zim && !loading) {
         const {search} = zim;
         if (search && search.length > 0) {
-            body = search.map(i => <Segment vertical key={i['path']}>
+            body = search.map(i => <div
+                key={i['path']}
+                style={{borderBottom: '1px solid var(--border)', paddingBottom: '1em', marginBottom: '1em'}}
+            >
                 <ZimSearchEntry zimId={id} onTag={localAddTag} onUntag={localUntag} entry={i}/>
-            </Segment>);
+            </div>);
         } else {
-            body = <p {...t}>No results</p>;
+            body = <p>No results</p>;
         }
     }
 
@@ -253,69 +229,52 @@ const ZimAccordion = ({data, index, activeIndex, onClick, searchStr, activeTags}
 
     const label = <Label color={estimate > 0 ? 'violet' : undefined}>{normalizeEstimate(estimate)}</Label>;
 
-    return <React.Fragment>
-        <AccordionTitle
-            index={index}
-            active={index === activeIndex}
-            onClick={() => onClick(index, activeIndex)}
-        >
-            <Header as='h3'>
-                <Icon name='dropdown'/> {title} {label}
-            </Header>
-        </AccordionTitle>
-        <AccordionContent active={index === activeIndex}>
+    return <Accordion.Item value={value}>
+        <Accordion.Control>
+            <Header as='h3' style={{marginBottom: 0}}>{title} {label}</Header>
+        </Accordion.Control>
+        <Accordion.Panel>
             <Header as='h4'>{date}</Header>
             {body}
             {paginator}
-        </AccordionContent>
-    </React.Fragment>
+        </Accordion.Panel>
+    </Accordion.Item>
 }
 
 const ZimsRefreshWarning = () => {
-    return <Message icon warning onClick={refreshFiles}>
-        <SIcon name='hand point right'/>
-        <Message.Content>
-            <Message.Header>No Zims have been indexed.</Message.Header>
+    return <div onClick={refreshFiles} style={{cursor: 'pointer'}}>
+        <Message kind='warning' icon='hand point right' title='No Zims have been indexed.'>
             <a href='#'>Click here</a> to refresh all your files.
-        </Message.Content>
-    </Message>;
+        </Message>
+    </div>;
 }
 
 export const ZimSearchView = ({suggestions, loading}) => {
-    const [activeIndex, setActiveIndex] = React.useState(null);
+    const [activeValue, setActiveValue] = React.useState(null);
     const {searchStr, activeTags, setTags} = useSearch();
     const {zimsEstimates} = suggestions;
 
-    const handleClick = (index, activeIndex_) => {
-        setActiveIndex(index === activeIndex_ ? -1 : index);
-    }
-
     let body;
     if (!_.isEmpty(zimsEstimates)) {
-        body = zimsEstimates.map((i, index) => <ZimAccordion
-            key={i['path']}
-            index={index}
-            activeIndex={activeIndex}
-            data={i}
-            searchStr={searchStr}
-            activeTags={activeTags}
-            onClick={handleClick}
-        />);
+        body = <Accordion value={activeValue} onChange={setActiveValue}>
+            {zimsEstimates.map(i => <ZimAccordionItem
+                key={i['path']}
+                value={String(i['id'])}
+                active={activeValue === String(i['id'])}
+                data={i}
+                searchStr={searchStr}
+                activeTags={activeTags}
+            />)}
+        </Accordion>;
     } else if (loading) {
-        body = <AccordionContent>
-            <Segment placeholder>
-                <Loader active={true}/>
-            </Segment>
-        </AccordionContent>;
+        body = <Panel><Loading/></Panel>;
     } else if (_.isEmpty(zimsEstimates)) {
         body = <ZimsRefreshWarning/>;
     }
 
     return <>
         <TagsQuerySelector onChange={(i, j) => setTags(i)}/>
-        <Accordion>
-            {body}
-        </Accordion>
+        {body}
     </>
 }
 
@@ -369,39 +328,36 @@ const ZimCatalogItemRow = ({item, subscriptions, iso_639_codes, fetchSubscriptio
         }
     }
 
-    const handleLanguageChange = (e, {value}) => {
-        if (e) {
-            e.preventDefault();
-        }
-        setLanguage(value);
-    }
-
     const languageOptions = languages.map(i => {
-        return {key: i, value: i, text: iso_639_codes[i]}
+        return {value: i, label: iso_639_codes[i]}
     });
-    const languageDropdown = <Dropdown fluid search selection
-                                       placeholder='Language'
-                                       options={languageOptions}
-                                       value={language}
-                                       disabled={wrolModeEnabled}
-                                       onChange={handleLanguageChange}
+    const languageDropdown = <Select
+        searchable
+        placeholder='Language'
+        data={languageOptions}
+        value={language}
+        disabled={wrolModeEnabled}
+        onChange={(value) => setLanguage(value)}
     />;
 
+    const isDestructive = subscription && !languageChange;
     const subscribeButton = <APIButton
-        color='grey'
+        role={isDestructive ? 'danger' : 'primary'}
+        confirmContent={isDestructive ? 'Are you sure you want to unsubscribe from this Zim?' : undefined}
+        confirmButton={isDestructive ? 'Unsubscribe' : undefined}
         disabled={pending}
         onClick={handleButton}
         obeyWROLMode={true}
     >
-        {subscription && !languageChange ? 'Unsubscribe' : 'Subscribe'}
+        {isDestructive ? 'Unsubscribe' : 'Subscribe'}
     </APIButton>
 
-    return <TableRow key={name}>
-        <TableCell>{name}</TableCell>
-        <TableCell>{languageDropdown}</TableCell>
-        <TableCell>{subscribeButton}</TableCell>
-        <TableCell>{humanFileSize(size)}</TableCell>
-    </TableRow>
+    return <Table.Row key={name}>
+        <Table.Cell>{name}</Table.Cell>
+        <Table.Cell>{languageDropdown}</Table.Cell>
+        <Table.Cell>{subscribeButton}</Table.Cell>
+        <Table.Cell>{humanFileSize(size)}</Table.Cell>
+    </Table.Row>
 }
 
 class ManageZim extends React.Component {
@@ -458,11 +414,11 @@ class ManageZim extends React.Component {
             popupContent='Enable/Disable searching this Zim file in the Global Search.'
         />
 
-        return <TableRow key={path}>
-            <TableCell>{path}</TableCell>
-            <TableCell>{humanFileSize(size)}</TableCell>
-            <TableCell>{toggle}</TableCell>
-        </TableRow>
+        return <Table.Row key={path}>
+            <Table.Cell>{path}</Table.Cell>
+            <Table.Cell>{humanFileSize(size)}</Table.Cell>
+            <Table.Cell>{toggle}</Table.Cell>
+        </Table.Row>
     }
 
     render() {
@@ -473,15 +429,9 @@ class ManageZim extends React.Component {
             {key: 'size', text: 'Size', sortBy: 'size', width: 2},
             {key: 'search', text: 'Search', sortBy: 'auto_search', width: 2},
         ];
-        let zimFilesBody = <Placeholder>
-            <PlaceholderHeader>
-                <PlaceholderLine/>
-                <PlaceholderLine/>
-            </PlaceholderHeader>
-        </Placeholder>;
+        let zimFilesBody = <Placeholder lines={2}/>;
         if (zims && zims.length >= 1) {
             zimFilesBody = <SortableTable
-                tableProps={{striped: true}}
                 data={zims}
                 rowFunc={(i, sortData) => this.zimFileTableRow(i, sortData, this.fetchZims.bind(this))}
                 rowKey='path'
@@ -505,12 +455,7 @@ class ManageZim extends React.Component {
             {key: 'subscription', text: 'Subscription', 'sortBy': null, width: 2},
             {key: 'size', text: 'Maximum Size', sortBy: 'size', width: 2},
         ];
-        let kiwixCatalog = <Placeholder>
-            <PlaceholderHeader>
-                <PlaceholderLine/>
-                <PlaceholderLine/>
-            </PlaceholderHeader>
-        </Placeholder>;
+        let kiwixCatalog = <Placeholder lines={2}/>;
         if (catalog && catalog.length > 0) {
             kiwixCatalog = <SortableTable
                 defaultSortColumn='name'
@@ -544,7 +489,7 @@ class ManageZim extends React.Component {
 }
 
 function ZimViewer({src = ZIM_VIEWER_URI, style = null}) {
-    const fallback = <Segment>
+    const fallback = <Panel>
         <Header as='h3'>Failed to fetch Zim service.</Header>
         <p>You may need to give permission to access the page: <a href={src}>{src}</a></p>
 
@@ -553,7 +498,7 @@ function ZimViewer({src = ZIM_VIEWER_URI, style = null}) {
 
         <p>Check the logs</p>
         <pre>journalctl -u wrolpi-kiwix</pre>
-    </Segment>;
+    </Panel>;
 
     return <IframeViewer title='zim' src={src} fallback={fallback} style={style}/>
 }
@@ -573,4 +518,4 @@ export function ZimRoute() {
             <Route path='manage' exact element={<ManageZim/>}/>
         </Routes>
     </div>
-}
\ No newline at end of file
+}
diff --git a/app/src/components/admin/ControllerPage.js b/app/src/components/admin/ControllerPage.js
index 01a18f51..9f52b8c1 100644
--- a/app/src/components/admin/ControllerPage.js
+++ b/app/src/components/admin/ControllerPage.js
@@ -1,6 +1,23 @@
 import React from 'react';
-import {Checkbox, Container, Dropdown, Form, Icon, Input} from "semantic-ui-react";
-import {Button, Confirm, Header, Loader, Modal, Segment, Table} from "../Theme";
+import {IconInfoCircle, IconPlayerEject} from '@tabler/icons-react';
+import {
+    Button,
+    Checkbox,
+    Confirm,
+    Group,
+    Header,
+    Icon,
+    IconButton,
+    Loading,
+    Message,
+    Modal,
+    Panel,
+    Select,
+    Status,
+    Table,
+    TextInput,
+    toast,
+} from "../ui";
 import {APIButton, BluetoothToggle, DesktopToggle, DirectorySearch, HandPointMessage, HotspotToggle, InfoMessage, ThrottleToggle, Toggle, VncToggle,} from "../Common";
 import {useDockerized, useMediaDirectory} from "../../hooks/customHooks";
 import {Media} from "../../contexts/contexts";
@@ -29,18 +46,18 @@ import {
     updateHotspotSettings,
 } from "../../api/controller";
 import QRCode from "react-qr-code";
-import {toast} from "../ui";
 import {RestartButton, ShutdownButton} from "./Settings";
-import Message from "semantic-ui-react/dist/commonjs/collections/Message";
 import {CONTROLLER_URI} from "../Vars";
 
 
-// Service status color mapping
-const statusColors = {
-    running: 'green',
-    stopped: 'red',
-    failed: 'red',
-    unknown: 'yellow',
+// Service status kind mapping. Status only knows complete/active/pending/failed,
+// so "stopped" and "unknown" both land on pending -- the Start/Stop button and
+// service name still tell them apart, this dot only carries running vs. failed.
+const statusKinds = {
+    running: 'complete',
+    stopped: 'pending',
+    failed: 'failed',
+    unknown: 'pending',
 };
 
 // Sort order within a group: problems first so they stay visible.
@@ -69,11 +86,11 @@ export const groupServices = (services) => {
 
 
 const linesOptions = [
-    {key: 100, text: '100 lines', value: 100},
-    {key: 250, text: '250 lines', value: 250},
-    {key: 500, text: '500 lines', value: 500},
-    {key: 1000, text: '1000 lines', value: 1000},
-    {key: 5000, text: '5000 lines', value: 5000},
+    {value: '100', label: '100 lines'},
+    {value: '250', label: '250 lines'},
+    {value: '500', label: '500 lines'},
+    {value: '1000', label: '1000 lines'},
+    {value: '5000', label: '5000 lines'},
 ];
 
 // Custom hook for service row state and handlers
@@ -157,9 +174,10 @@ function useServiceRow(service, onAction) {
         fetchLogs(linesCount, true); // Show loading on initial open
     };
 
-    const handleLinesChange = (e, {value}) => {
-        setLinesCount(value);
-        fetchLogs(value);
+    const handleLinesChange = (value) => {
+        const lines = parseInt(value, 10);
+        setLinesCount(lines);
+        fetchLogs(lines);
     };
 
     const handleDownloadLogs = () => {
@@ -175,7 +193,7 @@ function useServiceRow(service, onAction) {
     };
 
     const isRunning = service.status === 'running';
-    const statusColor = statusColors[service.status] || 'grey';
+    const statusKind = statusKinds[service.status] || 'pending';
 
     // Build view URL if service is viewable
     let viewUrl = null;
@@ -191,7 +209,7 @@ function useServiceRow(service, onAction) {
     return {
         loading, logsOpen, setLogsOpen, logs, logsLoading, linesCount, countdown, logsRef,
         handleAction, fetchLogs, handleViewLogs, handleLinesChange, handleDownloadLogs,
-        isRunning, statusColor, viewUrl
+        isRunning, statusKind, viewUrl
     };
 }
 
@@ -205,7 +223,6 @@ function ServiceLogsModal({
                               logsRef,
                               linesCount,
                               countdown,
-                              handleViewLogs,
                               handleLinesChange,
                               handleDownloadLogs,
                               fetchLogs
@@ -214,24 +231,22 @@ function ServiceLogsModal({
         <Modal
             open={logsOpen}
             onClose={() => setLogsOpen(false)}
-            onOpen={handleViewLogs}
-            trigger={<Button size='small' icon='file text' color='blue'/>}
             size='fullscreen'
         >
             <Modal.Header>Logs: {service.name}</Modal.Header>
             <Modal.Content scrolling>
                 {logsLoading ? (
-                    <Loader active inline='centered'/>
+                    <Loading/>
                 ) : (
                     <pre ref={logsRef} style={{
                         whiteSpace: 'pre-wrap',
                         wordWrap: 'break-word',
                         maxHeight: '400px',
                         overflow: 'auto',
-                        backgroundColor: '#1a1a1a',
-                        color: '#00ff00',
+                        background: 'var(--panel)',
+                        color: 'var(--text)',
                         padding: '1em',
-                        fontFamily: 'monospace',
+                        fontFamily: 'var(--font-mono)',
                         fontSize: '0.85em',
                     }}>
                         {logs}
@@ -239,17 +254,16 @@ function ServiceLogsModal({
                 )}
             </Modal.Content>
             <Modal.Actions>
-                <span style={{marginRight: '0.5em', color: '#888'}}>{countdown}s</span>
-                <Dropdown
-                    selection
-                    options={linesOptions}
-                    value={linesCount}
+                <span style={{marginRight: '0.5em', color: 'var(--muted)'}}>{countdown}s</span>
+                <Select
+                    data={linesOptions}
+                    value={String(linesCount)}
                     onChange={handleLinesChange}
                     style={{marginRight: 'auto'}}
                 />
-                <Button onClick={() => fetchLogs(linesCount)} color='blue' icon='refresh' content='Refresh'/>
-                <Button onClick={handleDownloadLogs} color='yellow' icon='download' content='Download'/>
-                <Button onClick={() => setLogsOpen(false)}>Close</Button>
+                <Button onClick={() => fetchLogs(linesCount)} role='primary' icon='refresh'>Refresh</Button>
+                <Button onClick={handleDownloadLogs} color='yellow' icon='download'>Download</Button>
+                <Button role='cancel' onClick={() => setLogsOpen(false)}>Close</Button>
             </Modal.Actions>
         </Modal>
     );
@@ -260,44 +274,51 @@ function MobileServiceRow({service, onAction}) {
     const {
         loading, logsOpen, setLogsOpen, logs, logsLoading, linesCount, countdown, logsRef,
         handleAction, fetchLogs, handleViewLogs, handleLinesChange, handleDownloadLogs,
-        isRunning, statusColor, viewUrl
+        isRunning, statusKind, viewUrl
     } = useServiceRow(service, onAction);
 
     return (
-        <Table.Row>
+        <Table.Row failed={service.status === 'failed'}>
             <Table.Cell>
-                <Icon name='circle' color={statusColor}/>
+                <Status kind={statusKind} plain/>
                 <strong>{service.name}</strong>
-                {service.description && <div style={{fontSize: '0.9em', color: '#888'}}>{service.description}</div>}
+                {service.description &&
+                    <div style={{fontSize: '0.9em', color: 'var(--muted)'}}>{service.description}</div>}
             </Table.Cell>
-            <Table.Cell textAlign='right'>
+            <Table.Cell numeric>
                 {isRunning ? (
-                    <Button
-                        size='small'
+                    <IconButton
                         icon='stop'
-                        color='red'
+                        label={`Stop ${service.name}`}
+                        role='danger'
                         disabled={loading}
                         loading={loading}
                         onClick={() => handleAction('Stop', stopService)}
                     />
                 ) : (
-                    <Button
-                        size='small'
+                    <IconButton
                         icon='play'
-                        color='green'
+                        label={`Start ${service.name}`}
+                        role='save'
                         disabled={loading}
                         loading={loading}
                         onClick={() => handleAction('Start', startService)}
                     />
                 )}
-                <Button
-                    size='small'
+                <IconButton
                     icon='refresh'
-                    color='yellow'
+                    label={`Restart ${service.name}`}
+                    role='retry'
                     disabled={loading}
                     loading={loading}
                     onClick={() => handleAction('Restart', restartService)}
                 />
+                <IconButton
+                    icon='file text'
+                    label={`View logs for ${service.name}`}
+                    role='primary'
+                    onClick={handleViewLogs}
+                />
                 <ServiceLogsModal
                     service={service}
                     logsOpen={logsOpen}
@@ -307,20 +328,19 @@ function MobileServiceRow({service, onAction}) {
                     logsRef={logsRef}
                     linesCount={linesCount}
                     countdown={countdown}
-                    handleViewLogs={handleViewLogs}
                     handleLinesChange={handleLinesChange}
                     handleDownloadLogs={handleDownloadLogs}
                     fetchLogs={fetchLogs}
                 />
                 {viewUrl && (
-                    <Button
-                        size='small'
+                    <IconButton
                         icon='external'
-                        as='a'
+                        label={`Open ${service.name}`}
+                        color='violet'
+                        component='a'
                         href={viewUrl}
                         target='_blank'
                         rel='noopener noreferrer'
-                        color='violet'
                     />
                 )}
             </Table.Cell>
@@ -333,45 +353,52 @@ function DesktopServiceRow({service, onAction, dockerized}) {
     const {
         loading, logsOpen, setLogsOpen, logs, logsLoading, linesCount, countdown, logsRef,
         handleAction, fetchLogs, handleViewLogs, handleLinesChange, handleDownloadLogs,
-        isRunning, statusColor, viewUrl
+        isRunning, statusKind, viewUrl
     } = useServiceRow(service, onAction);
 
     return (
-        <Table.Row>
+        <Table.Row failed={service.status === 'failed'}>
             <Table.Cell>
-                <Icon name='circle' color={statusColor}/>
+                <Status kind={statusKind} plain/>
                 <strong>{service.name}</strong>
-                {service.description && <div style={{fontSize: '0.9em', color: '#888'}}>{service.description}</div>}
+                {service.description &&
+                    <div style={{fontSize: '0.9em', color: 'var(--muted)'}}>{service.description}</div>}
             </Table.Cell>
             <Table.Cell>{service.port || '-'}</Table.Cell>
             <Table.Cell>
                 {isRunning ? (
-                    <Button
-                        size='small'
+                    <IconButton
                         icon='stop'
-                        color='red'
+                        label={`Stop ${service.name}`}
+                        role='danger'
                         disabled={loading}
                         loading={loading}
                         onClick={() => handleAction('Stop', stopService)}
                     />
                 ) : (
-                    <Button
-                        size='small'
+                    <IconButton
                         icon='play'
-                        color='green'
+                        label={`Start ${service.name}`}
+                        role='save'
                         disabled={loading}
                         loading={loading}
                         onClick={() => handleAction('Start', startService)}
                     />
                 )}
-                <Button
-                    size='small'
+                <IconButton
                     icon='refresh'
-                    color='yellow'
+                    label={`Restart ${service.name}`}
+                    role='retry'
                     disabled={loading}
                     loading={loading}
                     onClick={() => handleAction('Restart', restartService)}
                 />
+                <IconButton
+                    icon='file text'
+                    label={`View logs for ${service.name}`}
+                    role='primary'
+                    onClick={handleViewLogs}
+                />
                 <ServiceLogsModal
                     service={service}
                     logsOpen={logsOpen}
@@ -381,20 +408,19 @@ function DesktopServiceRow({service, onAction, dockerized}) {
                     logsRef={logsRef}
                     linesCount={linesCount}
                     countdown={countdown}
-                    handleViewLogs={handleViewLogs}
                     handleLinesChange={handleLinesChange}
                     handleDownloadLogs={handleDownloadLogs}
                     fetchLogs={fetchLogs}
                 />
                 {viewUrl && (
-                    <Button
-                        size='small'
+                    <IconButton
                         icon='external'
-                        as='a'
+                        label={`Open ${service.name}`}
+                        color='violet'
+                        component='a'
                         href={viewUrl}
                         target='_blank'
                         rel='noopener noreferrer'
-                        color='violet'
                     />
                 )}
             </Table.Cell>
@@ -472,18 +498,18 @@ function ServicesSection() {
     }, []);
 
     if (loading && services.length === 0) {
-        return <Segment>
+        return <Panel>
             <Header as='h3'>Services</Header>
-            <Loader active inline='centered'/>
-        </Segment>;
+            <Loading/>
+        </Panel>;
     }
 
     if (error) {
-        return <Segment>
+        return <Panel>
             <Header as='h3'>Services</Header>
-            <p style={{color: 'red'}}>Error loading services: {error}</p>
-            <Button onClick={fetchServices}>Retry</Button>
-        </Segment>;
+            <Message kind='error'>Error loading services: {error}</Message>
+            <Button role='retry' icon='refresh' onClick={fetchServices}>Retry</Button>
+        </Panel>;
     }
 
     const restartButton = (colSpan) => (
@@ -491,13 +517,13 @@ function ServicesSection() {
             <Table.Row>
                 <Table.HeaderCell colSpan={colSpan}>
                     <APIButton
-                        color='yellow'
+                        role='retry'
+                        icon='refresh'
                         onClick={handleRestartServices}
                         confirmContent='Are you sure you want to restart all WROLPi services?'
                         confirmButton='Restart Services'
                         disabled={restarting}
                     >
-                        <Icon name='refresh'/>
                         {restarting ? 'Restarting...' : 'Restart All Services'}
                     </APIButton>
                 </Table.HeaderCell>
@@ -536,14 +562,11 @@ function ServicesSection() {
     };
 
     return (
-        <Segment>
-            <Header as='h3'>
-                <Icon name='server'/>
-                Services
-            </Header>
+        <Panel>
+            <Header as='h3' icon='server'>Services</Header>
             {/* Mobile table - 2 columns */}
             <Media at='mobile'>
-                <Table unstackable striped size='small'>
+                <Table>
                     <Table.Header>
                         <Table.Row>
                             <Table.HeaderCell>Service</Table.HeaderCell>
@@ -558,7 +581,7 @@ function ServicesSection() {
             </Media>
             {/* Desktop table - full columns */}
             <Media greaterThanOrEqual='tablet'>
-                <Table unstackable striped>
+                <Table>
                     <Table.Header>
                         <Table.Row>
                             <Table.HeaderCell>Service</Table.HeaderCell>
@@ -576,19 +599,19 @@ function ServicesSection() {
             {services.length === 0 && (
                 <p>No services found. Services may not be available in this environment.</p>
             )}
-        </Segment>
+        </Panel>
     );
 }
 
 
 // Helper to get health status color from SMART assessment
 const getHealthColor = (assessment) => {
-    if (!assessment) return 'grey';
+    if (!assessment) return 'var(--muted)';
     const upper = assessment.toUpperCase();
-    if (upper === 'PASS') return 'green';
-    if (upper === 'WARN') return 'yellow';
-    if (upper === 'FAIL') return 'red';
-    return 'grey';
+    if (upper === 'PASS') return 'var(--green)';
+    if (upper === 'WARN') return 'var(--amber)';
+    if (upper === 'FAIL') return 'var(--red)';
+    return 'var(--muted)';
 };
 
 // Helper to format power-on hours
@@ -610,11 +633,10 @@ function SmartDetailsModal({drive, open, onClose}) {
     return (
         <Modal open={open} onClose={onClose} size='small'>
             <Modal.Header>
-                <Icon name='heartbeat'/>
-                SMART Details: {drive.device}
+                <Icon name='heartbeat'/> SMART Details: {drive.device}
             </Modal.Header>
             <Modal.Content>
-                <Table definition unstackable>
+                <Table>
                     <Table.Body>
                         <Table.Row>
                             <Table.Cell width={6}>Model</Table.Cell>
@@ -631,7 +653,7 @@ function SmartDetailsModal({drive, open, onClose}) {
                         <Table.Row>
                             <Table.Cell>Assessment</Table.Cell>
                             <Table.Cell>
-                                <Icon name='circle' color={healthColor}/>
+                                <span style={{color: healthColor}}>&#9679;</span>{' '}
                                 {drive.assessment || drive.health || 'Unknown'}
                                 {drive.smart_limited
                                     ? ' (limited — USB enclosure reports health only, no attributes)'
@@ -652,7 +674,7 @@ function SmartDetailsModal({drive, open, onClose}) {
                         </Table.Row>
                         <Table.Row>
                             <Table.Cell>Reallocated Sectors</Table.Cell>
-                            <Table.Cell style={{color: drive.reallocated_sectors > 0 ? 'orange' : 'inherit'}}>
+                            <Table.Cell style={{color: drive.reallocated_sectors > 0 ? 'var(--amber)' : 'inherit'}}>
                                 {drive.reallocated_sectors !== null && drive.reallocated_sectors !== undefined
                                     ? drive.reallocated_sectors
                                     : '-'}
@@ -660,7 +682,7 @@ function SmartDetailsModal({drive, open, onClose}) {
                         </Table.Row>
                         <Table.Row>
                             <Table.Cell>Pending Sectors</Table.Cell>
-                            <Table.Cell style={{color: drive.pending_sectors > 0 ? 'orange' : 'inherit'}}>
+                            <Table.Cell style={{color: drive.pending_sectors > 0 ? 'var(--amber)' : 'inherit'}}>
                                 {drive.pending_sectors !== null && drive.pending_sectors !== undefined
                                     ? drive.pending_sectors
                                     : '-'}
@@ -668,7 +690,7 @@ function SmartDetailsModal({drive, open, onClose}) {
                         </Table.Row>
                         <Table.Row>
                             <Table.Cell>Uncorrectable Sectors</Table.Cell>
-                            <Table.Cell style={{color: drive.offline_uncorrectable > 0 ? 'orange' : 'inherit'}}>
+                            <Table.Cell style={{color: drive.offline_uncorrectable > 0 ? 'var(--amber)' : 'inherit'}}>
                                 {drive.offline_uncorrectable !== null && drive.offline_uncorrectable !== undefined
                                     ? drive.offline_uncorrectable
                                     : '-'}
@@ -682,7 +704,7 @@ function SmartDetailsModal({drive, open, onClose}) {
                 </Table>
             </Modal.Content>
             <Modal.Actions>
-                <Button onClick={onClose}>Close</Button>
+                <Button role='cancel' onClick={onClose}>Close</Button>
             </Modal.Actions>
         </Modal>
     );
@@ -797,8 +819,7 @@ function MountModal({disk, open, onClose, onMount}) {
         return (
             <Modal open={open} onClose={handleCancel} size='small'>
                 <Modal.Header>
-                    <Icon name='warning sign' color='yellow'/>
-                    Existing Files Detected
+                    <Icon name='warning sign'/> Existing Files Detected
                 </Modal.Header>
                 <Modal.Content>
                     <p>
@@ -808,7 +829,7 @@ function MountModal({disk, open, onClose, onMount}) {
                     <p>
                         Found <strong>{entries}</strong> ({formatBytes(shadowed.size_bytes)}) at the mount target.
                     </p>
-                    <p style={{color: '#a00'}}>
+                    <p style={{color: 'var(--red)'}}>
                         Those files will continue to consume space on the underlying filesystem
                         (typically the SD card on a Raspberry Pi) and can fill it up.
                     </p>
@@ -817,9 +838,9 @@ function MountModal({disk, open, onClose, onMount}) {
                     </p>
                 </Modal.Content>
                 <Modal.Actions>
-                    <Button onClick={handleCancel} disabled={loading}>Cancel</Button>
-                    <Button color='yellow' onClick={handleForceMount} loading={loading} disabled={loading}>
-                        <Icon name='exclamation triangle'/>
+                    <Button role='cancel' onClick={handleCancel} disabled={loading}>Cancel</Button>
+                    <Button role='retry' icon='exclamation triangle' onClick={handleForceMount} loading={loading}
+                            disabled={loading}>
                         Mount Anyway
                     </Button>
                 </Modal.Actions>
@@ -830,41 +851,34 @@ function MountModal({disk, open, onClose, onMount}) {
     return (
         <Modal open={open} onClose={onClose} size='small'>
             <Modal.Header>
-                <Icon name='disk'/>
-                Mount Disk: {disk.name}
+                <Icon name='disk'/> Mount Disk: {disk.name}
             </Modal.Header>
             <Modal.Content>
-                <Form>
-                    <Form.Field>
-                        <label>Mount Point</label>
-                        <Input
-                            autoFocus
-                            value={mountPoint}
-                            onChange={(e) => setMountPoint(e.target.value)}
-                            placeholder="/media/..."
-                            fluid
-                        />
-                    </Form.Field>
-                    <Form.Field>
-                        <Checkbox
-                            label="Persistent (survive reboots)"
-                            checked={persist}
-                            onChange={(e, {checked}) => setPersist(checked)}
-                        />
-                    </Form.Field>
-                    {disk.fstype && (
-                        <p style={{color: '#888', fontSize: '0.9em'}}>
-                            Filesystem: {disk.fstype}
-                            {disk.label && ` | Label: ${disk.label}`}
-                            {disk.size && ` | Size: ${formatSize(disk.size)}`}
-                        </p>
-                    )}
-                </Form>
+                <TextInput
+                    autoFocus
+                    label='Mount Point'
+                    value={mountPoint}
+                    onChange={(e) => setMountPoint(e.target.value)}
+                    placeholder="/media/..."
+                />
+                <div style={{marginTop: '0.8em'}}>
+                    <Checkbox
+                        label="Persistent (survive reboots)"
+                        checked={persist}
+                        onChange={(e) => setPersist(e.currentTarget.checked)}
+                    />
+                </div>
+                {disk.fstype && (
+                    <p style={{color: 'var(--muted)', fontSize: '0.9em'}}>
+                        Filesystem: {disk.fstype}
+                        {disk.label && ` | Label: ${disk.label}`}
+                        {disk.size && ` | Size: ${formatSize(disk.size)}`}
+                    </p>
+                )}
             </Modal.Content>
             <Modal.Actions>
-                <Button onClick={onClose} disabled={loading}>Cancel</Button>
-                <Button color='green' onClick={handleMount} loading={loading} disabled={loading}>
-                    <Icon name='check'/>
+                <Button role='cancel' onClick={onClose} disabled={loading}>Cancel</Button>
+                <Button role='save' icon='check' onClick={handleMount} loading={loading} disabled={loading}>
                     Mount
                 </Button>
             </Modal.Actions>
@@ -1009,35 +1023,29 @@ function DiskSection() {
 
     if (dockerized) {
         return (
-            <Segment>
-                <Header as='h3'>
-                    <Icon name='disk'/>
-                    Disk Management
-                </Header>
+            <Panel>
+                <Header as='h3' icon='disk'>Disk Management</Header>
                 <p>Disk management is not available in Docker environments.</p>
-            </Segment>
+            </Panel>
         );
     }
 
     if (loading) {
-        return <Segment>
+        return <Panel>
             <Header as='h3'>Disk Management</Header>
-            <Loader active inline='centered'/>
-        </Segment>;
+            <Loading/>
+        </Panel>;
     }
 
     return (
-        <Segment>
-            <Header as='h3'>
-                <Icon name='disk'/>
-                Disk Management
-            </Header>
+        <Panel>
+            <Header as='h3' icon='disk'>Disk Management</Header>
 
-            {error && <p style={{color: 'orange'}}>Some disk information unavailable: {error}</p>}
+            {error && <Message kind='warning'>Some disk information unavailable: {error}</Message>}
 
             <Header as='h4'>Disks</Header>
             {disks.length > 0 ? (
-                <Table unstackable striped compact>
+                <Table>
                     <Table.Header>
                         <Table.Row>
                             <Table.HeaderCell>Name</Table.HeaderCell>
@@ -1067,7 +1075,7 @@ function DiskSection() {
                                         {isMounted ? (
                                             <span>{disk.mountpoint}</span>
                                         ) : (
-                                            <span style={{color: '#888'}}>-</span>
+                                            <span style={{color: 'var(--muted)'}}>-</span>
                                         )}
                                     </Table.Cell>
                                     <Table.Cell>
@@ -1078,28 +1086,30 @@ function DiskSection() {
                                                 label={persistent ? 'Enabled' : 'Disabled'}
                                             />
                                         ) : (
-                                            <span style={{color: '#888'}}>-</span>
+                                            <span style={{color: 'var(--muted)'}}>-</span>
                                         )}
                                     </Table.Cell>
                                     <Table.Cell>
                                         {isMounted && isSystemMount ? (
-                                            <span style={{color: '#888'}}>System</span>
+                                            <span style={{color: 'var(--muted)'}}>System</span>
                                         ) : isMounted ? (
                                             <Button
-                                                size='small'
-                                                color='red'
-                                                icon='eject'
-                                                content='Unmount'
+                                                size='sm'
+                                                role='danger'
+                                                icon={IconPlayerEject}
                                                 onClick={() => handleUnmountClick(disk.mountpoint)}
-                                            />
+                                            >
+                                                Unmount
+                                            </Button>
                                         ) : (
                                             <Button
-                                                size='small'
-                                                color='green'
+                                                size='sm'
+                                                role='save'
                                                 icon='plug'
-                                                content='Mount'
                                                 onClick={() => handleOpenMountModal(disk)}
-                                            />
+                                            >
+                                                Mount
+                                            </Button>
                                         )}
                                     </Table.Cell>
                                 </Table.Row>
@@ -1113,9 +1123,10 @@ function DiskSection() {
 
             <Header as='h4'>SMART Health</Header>
             {!smartAvailable ? (
-                <p style={{color: '#888'}}>SMART monitoring not available (pySMART not installed or not supported)</p>
+                <p style={{color: 'var(--muted)'}}>SMART monitoring not available (pySMART not installed or not
+                    supported)</p>
             ) : smartDrives.length > 0 ? (
-                <Table unstackable striped compact>
+                <Table>
                     <Table.Header>
                         <Table.Row>
                             <Table.HeaderCell>Device</Table.HeaderCell>
@@ -1129,10 +1140,9 @@ function DiskSection() {
                             <Table.Row key={drive.device}>
                                 <Table.Cell>{drive.device}</Table.Cell>
                                 <Table.Cell>
-                                    <Icon
-                                        name='circle'
-                                        color={getHealthColor(drive.health || drive.assessment)}
-                                    />
+                                    <span style={{color: getHealthColor(drive.health || drive.assessment)}}>
+                                        &#9679;
+                                    </span>{' '}
                                     {drive.health || drive.assessment || 'Unknown'}
                                     {drive.smart_limited ? ' (limited)' : ''}
                                 </Table.Cell>
@@ -1143,11 +1153,13 @@ function DiskSection() {
                                 </Table.Cell>
                                 <Table.Cell>
                                     <Button
-                                        size='small'
-                                        icon='info'
-                                        content='Details'
+                                        size='sm'
+                                        role='cancel'
+                                        icon={IconInfoCircle}
                                         onClick={() => handleShowDetails(drive)}
-                                    />
+                                    >
+                                        Details
+                                    </Button>
                                 </Table.Cell>
                             </Table.Row>
                         ))}
@@ -1172,12 +1184,19 @@ function DiskSection() {
 
             <Confirm
                 open={unmountConfirmOpen}
-                header='Unmount Disk'
-                content={unmountTarget === PRIMARY_MOUNT ? (
-                    <div className='content'>
+                title='Unmount Disk'
+                destructive
+                confirmLabel='Unmount'
+                onCancel={() => {
+                    setUnmountConfirmOpen(false);
+                    setUnmountTarget(null);
+                }}
+                onConfirm={handleUnmountConfirm}
+            >
+                {unmountTarget === PRIMARY_MOUNT ? (
+                    <div>
                         <p>Are you sure you want to unmount <code>{unmountTarget}</code>?</p>
                         <p>
-                            <Icon name='warning sign' color='yellow'/>
                             This is the primary WROLPi drive. The WROLPi API service will
                             be <strong>stopped</strong> before unmounting, and your media will be
                             unavailable until a drive is mounted at <code>{PRIMARY_MOUNT}</code> and
@@ -1185,19 +1204,12 @@ function DiskSection() {
                         </p>
                     </div>
                 ) : `Are you sure you want to unmount ${unmountTarget}?`}
-                onCancel={() => {
-                    setUnmountConfirmOpen(false);
-                    setUnmountTarget(null);
-                }}
-                onConfirm={handleUnmountConfirm}
-                confirmButton='Unmount'
-            />
+            </Confirm>
 
-            <Button onClick={fetchDiskInfo} style={{marginTop: '1em'}}>
-                <Icon name='refresh'/>
+            <Button role='cancel' icon='refresh' onClick={fetchDiskInfo} style={{marginTop: '1em'}}>
                 Refresh
             </Button>
-        </Segment>
+        </Panel>
     );
 }
 
@@ -1271,35 +1283,29 @@ function SambaSection() {
     };
 
     if (loading) {
-        return <Segment><Loader active inline='centered'/></Segment>;
+        return <Panel><Loading/></Panel>;
     }
 
     if (!status || !status.available) {
         if (dockerized) return null;
         return (
-            <Segment>
-                <Header as='h3'>
-                    <Icon name='folder open'/>
-                    Network Shares (Samba)
-                </Header>
-                <Message info>Samba is not available on this system.</Message>
-            </Segment>
+            <Panel>
+                <Header as='h3' icon='folder open'>Network Shares (Samba)</Header>
+                <Message kind='info'>Samba is not available on this system.</Message>
+            </Panel>
         );
     }
 
     const shares = status.shares || [];
 
     return (
-        <Segment>
-            <Header as='h3'>
-                <Icon name='folder open'/>
-                Network Shares (Samba)
-            </Header>
+        <Panel>
+            <Header as='h3' icon='folder open'>Network Shares (Samba)</Header>
 
             <p>Configure directories to share over the local network. Start the smbd service to activate sharing.</p>
 
             {shares.length > 0 && (
-                <Table celled style={{marginTop: '1em'}}>
+                <Table style={{marginTop: '1em'}}>
                     <Table.Header>
                         <Table.Row>
                             <Table.HeaderCell>Name</Table.HeaderCell>
@@ -1317,10 +1323,11 @@ function SambaSection() {
                                 <Table.Cell>{share.read_only ? 'Yes' : 'No'}</Table.Cell>
                                 <Table.Cell>{share.comment}</Table.Cell>
                                 <Table.Cell>
-                                    <Button
-                                        size='tiny'
-                                        color='red'
+                                    <IconButton
                                         icon='trash'
+                                        label={`Remove share "${share.name}"`}
+                                        role='danger'
+                                        size='xs'
                                         disabled={actionLoading}
                                         onClick={() => setRemoveConfirmName(share.name)}
                                     />
@@ -1333,80 +1340,83 @@ function SambaSection() {
 
             <Confirm
                 open={removeConfirmName !== null}
-                header='Remove Share'
-                content={`Remove the share "${removeConfirmName}"?`}
-                confirmButton='Remove'
+                title='Remove Share'
+                confirmLabel='Remove'
+                destructive
                 onCancel={() => setRemoveConfirmName(null)}
                 onConfirm={() => handleRemoveShare(removeConfirmName)}
-            />
+            >
+                {`Remove the share "${removeConfirmName}"?`}
+            </Confirm>
 
             <div style={{marginTop: '1em'}}>
                 <Button
+                    role='primary'
                     icon='plus'
-                    content='Add Share'
                     onClick={() => setAddOpen(true)}
                     disabled={actionLoading}
-                />
+                >
+                    Add Share
+                </Button>
             </div>
 
-            <Modal open={addOpen} onClose={() => { setAddOpen(false); setShareAll(true); }} size='small'>
+            <Modal open={addOpen} onClose={() => {
+                setAddOpen(false);
+                setShareAll(true);
+            }} size='small'>
                 <Modal.Header>Add Samba Share</Modal.Header>
                 <Modal.Content>
-                    <Form>
-                        <Form.Field>
-                            <label>Share Name</label>
-                            <Input
-                                placeholder='e.g. Documents'
-                                value={newName}
-                                onChange={(e, {value}) => setNewName(value)}
+                    <TextInput
+                        label='Share Name'
+                        placeholder='e.g. Documents'
+                        value={newName}
+                        onChange={(e) => setNewName(e.target.value)}
+                    />
+                    <div style={{marginTop: '0.8em'}}>
+                        <Checkbox
+                            label='Share all files'
+                            checked={shareAll}
+                            onChange={(e) => setShareAll(e.currentTarget.checked)}
+                        />
+                    </div>
+                    {!shareAll && (
+                        <div style={{marginTop: '0.8em'}}>
+                            <label>Path</label>
+                            <DirectorySearch
+                                onSelect={setNewPath}
+                                value={newPath}
                             />
-                        </Form.Field>
-                        <Form.Field>
-                            <Checkbox
-                                label='Share all files'
-                                checked={shareAll}
-                                onChange={(e, {checked}) => setShareAll(checked)}
-                            />
-                        </Form.Field>
-                        {!shareAll && (
-                            <Form.Field>
-                                <label>Path</label>
-                                <DirectorySearch
-                                    onSelect={setNewPath}
-                                    value={newPath}
-                                />
-                            </Form.Field>
-                        )}
-                        <Form.Field>
-                            <Checkbox
-                                label='Read Only'
-                                checked={newReadOnly}
-                                onChange={(e, {checked}) => setNewReadOnly(checked)}
-                            />
-                        </Form.Field>
-                        <Form.Field>
-                            <label>Comment (optional)</label>
-                            <Input
-                                placeholder='Description of this share'
-                                value={newComment}
-                                onChange={(e, {value}) => setNewComment(value)}
-                            />
-                        </Form.Field>
-                    </Form>
+                        </div>
+                    )}
+                    <div style={{marginTop: '0.8em'}}>
+                        <Checkbox
+                            label='Read Only'
+                            checked={newReadOnly}
+                            onChange={(e) => setNewReadOnly(e.currentTarget.checked)}
+                        />
+                    </div>
+                    <TextInput
+                        style={{marginTop: '0.8em'}}
+                        label='Comment (optional)'
+                        placeholder='Description of this share'
+                        value={newComment}
+                        onChange={(e) => setNewComment(e.target.value)}
+                    />
                 </Modal.Content>
                 <Modal.Actions>
-                    <Button onClick={() => setAddOpen(false)}>Cancel</Button>
+                    <Button role='cancel' onClick={() => setAddOpen(false)}>Cancel</Button>
                     <Button
-                        color='green'
+                        role='save'
                         icon='plus'
-                        content='Add Share'
                         disabled={!newName.trim() || actionLoading}
                         loading={actionLoading}
                         onClick={handleAddShare}
-                    />
+                    >
+                        Add Share
+                    </Button>
                 </Modal.Actions>
             </Modal>
-        </Segment>
+        </Panel>
     );
 }
 
@@ -1493,99 +1503,93 @@ function HotspotSettingsForm() {
     };
 
     if (loading) {
-        return <Segment>
-            <Header as='h4'>
-                <Icon name='wifi'/>
-                Hotspot Settings
-            </Header>
-            <Loader active inline size='small'/>
-        </Segment>;
+        return <Panel>
+            <Header as='h4' icon='wifi'>Hotspot Settings</Header>
+            <Loading size='xs'/>
+        </Panel>;
     }
 
     // Keep the saved device selectable even if it is not currently present
     // (e.g. a USB WiFi dongle is unplugged).
     const deviceOptions = [...new Set([...devices, form.device].filter(Boolean))]
-        .map(device => ({key: device, value: device, text: device}));
+        .map(device => ({value: device, label: device}));
 
     // Keep the saved protocol selectable even if the device does not report it.
     const protocolOptions = [...new Set([...protocols, form.protocol].filter(Boolean))]
-        .map(protocol => ({key: protocol, value: protocol, text: hotspotProtocolLabels[protocol] || protocol}));
+        .map(protocol => ({value: protocol, label: hotspotProtocolLabels[protocol] || protocol}));
 
     // Special string which allows a mobile device to connect to a specific Wi-Fi.
     // The WPA QR format requires backslash-escaping of \ ; , " in the SSID and password.
     const escapeWifi = (s) => s.replace(/([\\;,"])/g, '\\$1');
     const qrCodeValue = `WIFI:S:${escapeWifi(form.ssid)};T:WPA;P:${escapeWifi(form.password)};;`;
 
-    return <Segment>
-        <Header as='h4'>
-            <Icon name='wifi'/>
-            Hotspot Settings
-        </Header>
-        <Form>
-            <Form.Group widths='equal'>
-                <Form.Input
-                    label='Hotspot SSID'
-                    value={form.ssid}
-                    disabled={dockerized || saving}
-                    onChange={(e, {value}) => setForm({...form, ssid: value})}
-                />
-                <Form.Input
-                    label='Hotspot Password'
-                    value={form.password}
-                    disabled={dockerized || saving}
-                    onChange={(e, {value}) => setForm({...form, password: value})}
-                />
-                <Form.Dropdown
-                    selection
-                    label='Hotspot Device'
-                    placeholder='No WiFi devices found'
-                    options={deviceOptions}
-                    value={form.device}
-                    disabled={dockerized || saving}
-                    onChange={(e, {value}) => setForm({...form, device: value})}
-                />
-                <Form.Dropdown
-                    selection
-                    label='Hotspot Protocol'
-                    placeholder='No protocols supported'
-                    options={protocolOptions}
-                    value={form.protocol}
-                    disabled={dockerized || saving}
-                    onChange={(e, {value}) => setForm({...form, protocol: value})}
-                />
-            </Form.Group>
+    return <Panel>
+        <Header as='h4' icon='wifi'>Hotspot Settings</Header>
+        <Group grow align='flex-start'>
+            <TextInput
+                label='Hotspot SSID'
+                value={form.ssid}
+                disabled={dockerized || saving}
+                onChange={(e) => setForm({...form, ssid: e.target.value})}
+            />
+            <TextInput
+                label='Hotspot Password'
+                value={form.password}
+                disabled={dockerized || saving}
+                onChange={(e) => setForm({...form, password: e.target.value})}
+            />
+            <Select
+                label='Hotspot Device'
+                placeholder='No WiFi devices found'
+                data={deviceOptions}
+                value={form.device}
+                disabled={dockerized || saving}
+                onChange={(value) => setForm({...form, device: value})}
+            />
+            <Select
+                label='Hotspot Protocol'
+                placeholder='No protocols supported'
+                data={protocolOptions}
+                value={form.protocol}
+                disabled={dockerized || saving}
+                onChange={(value) => setForm({...form, protocol: value})}
+            />
+        </Group>
+        <div style={{marginTop: '0.8em'}}>
             <Button
                 color='violet'
                 disabled={dockerized}
                 loading={saving}
                 onClick={handleSave}
             >Save</Button>
-            <Modal closeIcon
-                   onClose={() => setQrOpen(false)}
-                   onOpen={() => setQrOpen(true)}
-                   open={qrOpen}
-                   trigger={<Button icon='qrcode' color='violet'/>}
-            >
+            <IconButton
+                icon='qrcode'
+                label='Scan this code to join the hotspot'
+                color='violet'
+                style={{marginLeft: '0.5em'}}
+                onClick={() => setQrOpen(true)}
+            />
+            <Modal open={qrOpen} onClose={() => setQrOpen(false)} closeIcon>
                 <Modal.Header>Scan this code to join the hotspot</Modal.Header>
                 <Modal.Content>
-                    <div style={{display: 'inline-block', backgroundColor: '#ffffff', padding: '1em'}}>
+                    {/* `media`: filtered as a unit by night mode; a QR code needs real black-on-white
+                        contrast to scan, so it is exempted the same way DonatePage's and Share's are. */}
+                    <div className='media'
+                         style={{display: 'inline-block', backgroundColor: '#ffffff', padding: '1em'}}>
                         <QRCode value={qrCodeValue} size={300}/>
                     </div>
                 </Modal.Content>
             </Modal>
-        </Form>
-    </Segment>;
+        </div>
+    </Panel>;
 }
 
 function AdminControlsSection() {
     const dockerized = useDockerized();
 
     return (
-        <Segment>
-            <Header as='h3'>
-                <Icon name='settings'/>
-                Hardware Controls
-            </Header>
+        <Panel>
+            <Header as='h3' icon='settings'>Hardware Controls</Header>
 
             <HotspotToggle/>
             <BluetoothToggle/>
@@ -1601,18 +1605,18 @@ function AdminControlsSection() {
                     <ShutdownButton/>
                 </div>
             )}
-        </Segment>
+        </Panel>
     );
 }
 
 export function ControllerPage() {
     return (
-        <Container fluid>
+        <div>
             <AdminControlsSection/>
             <ServicesSection/>
             <SambaSection/>
             <DiskSection/>
-        </Container>
+        </div>
     );
 }
 
diff --git a/app/src/components/admin/ControllerPage.test.js b/app/src/components/admin/ControllerPage.test.js
index 9a1f789a..62ddad71 100644
--- a/app/src/components/admin/ControllerPage.test.js
+++ b/app/src/components/admin/ControllerPage.test.js
@@ -1,7 +1,9 @@
 import React from 'react';
-import {fireEvent, render, screen, waitFor} from '@testing-library/react';
+import {fireEvent, render, screen, waitFor, within} from '@testing-library/react';
 import {BrowserRouter} from 'react-router';
+import {MantineProvider} from '@mantine/core';
 import {ThemeContext, SettingsContext} from '../../contexts/contexts';
+import {cssVariablesResolver, mantineTheme} from '../../themes/mantine';
 import {ControllerPage} from './ControllerPage';
 
 // Mock the controller API
@@ -134,11 +136,13 @@ const defaultSettings = {
 const renderControllerPage = () => {
     return render(
         <BrowserRouter>
-            <ThemeContext.Provider value={defaultTheme}>
-                <SettingsContext.Provider value={defaultSettings}>
-                    <ControllerPage/>
-                </SettingsContext.Provider>
-            </ThemeContext.Provider>
+            <MantineProvider theme={mantineTheme} cssVariablesResolver={cssVariablesResolver}>
+                <ThemeContext.Provider value={defaultTheme}>
+                    <SettingsContext.Provider value={defaultSettings}>
+                        <ControllerPage/>
+                    </SettingsContext.Provider>
+                </ThemeContext.Provider>
+            </MantineProvider>
         </BrowserRouter>
     );
 };
@@ -279,9 +283,11 @@ describe('DiskSection primary unmount', () => {
             expect(screen.getByText(/API service will/)).toBeInTheDocument();
         });
 
-        // Semantic's Confirm renders confirmButton='Unmount' as the last match.
-        const buttons = screen.getAllByText('Unmount');
-        fireEvent.click(buttons[buttons.length - 1]);
+        // The Confirm modal is portaled to the end of <body>, so it renders
+        // *before* the page content in DOM order -- scope the query to the
+        // dialog rather than assuming which match comes last.
+        const dialog = screen.getByRole('dialog');
+        fireEvent.click(within(dialog).getByText('Unmount'));
 
         await waitFor(() => {
             expect(controllerApi.unmountDisk).toHaveBeenCalledWith('/media/wrolpi');
diff --git a/app/src/components/admin/Downloads.js b/app/src/components/admin/Downloads.js
index 70ee7c5c..93526f1a 100644
--- a/app/src/components/admin/Downloads.js
+++ b/app/src/components/admin/Downloads.js
@@ -27,20 +27,19 @@ import {
     WROLModeMessage
 } from "../Common";
 import {
-    Button as SButton,
+    Button,
     ButtonGroup,
     Checkbox,
+    Header,
+    IconButton,
     Label,
     Loader,
-    PlaceholderLine,
-    TableBody,
-    TableCell,
-    TableFooter,
-    TableHeader,
-    TableHeaderCell,
-    TableRow
-} from "semantic-ui-react";
-import {Button, Header, Modal, Placeholder, Progress, Segment, Table} from "../Theme";
+    Modal,
+    Panel,
+    Placeholder,
+    Progress,
+    Table,
+} from "../ui";
 import {useDownloads} from "../../hooks/customHooks";
 import {
     EditArchiveDownloadForm,
@@ -70,35 +69,32 @@ function DownloadProgressModal({progress, url}) {
             <Modal.Content>
                 <Progress
                     percent={progress.percent}
-                    progress
-                    indicating
                     color={navColor}
-                >
-                    {humanFileSize(progress.bytes_downloaded)} / {humanFileSize(progress.total_bytes)}
-                </Progress>
-                <Table definition>
-                    <TableBody>
-                        <TableRow>
-                            <TableCell width={4}>Speed</TableCell>
-                            <TableCell>{speedText}</TableCell>
-                        </TableRow>
-                        <TableRow>
-                            <TableCell>ETA</TableCell>
-                            <TableCell>{progress.eta || 'Calculating...'}</TableCell>
-                        </TableRow>
-                        <TableRow>
-                            <TableCell>Downloaded</TableCell>
-                            <TableCell>{humanFileSize(progress.bytes_downloaded)} / {humanFileSize(progress.total_bytes)}</TableCell>
-                        </TableRow>
-                        {url && <TableRow>
-                            <TableCell>URL</TableCell>
-                            <TableCell style={{wordBreak: 'break-all'}}>{url}</TableCell>
-                        </TableRow>}
-                    </TableBody>
+                    label={`${humanFileSize(progress.bytes_downloaded)} / ${humanFileSize(progress.total_bytes)}`}
+                />
+                <Table>
+                    <Table.Body>
+                        <Table.Row>
+                            <Table.Cell style={{fontWeight: 600}}>Speed</Table.Cell>
+                            <Table.Cell>{speedText}</Table.Cell>
+                        </Table.Row>
+                        <Table.Row>
+                            <Table.Cell style={{fontWeight: 600}}>ETA</Table.Cell>
+                            <Table.Cell>{progress.eta || 'Calculating...'}</Table.Cell>
+                        </Table.Row>
+                        <Table.Row>
+                            <Table.Cell style={{fontWeight: 600}}>Downloaded</Table.Cell>
+                            <Table.Cell>{humanFileSize(progress.bytes_downloaded)} / {humanFileSize(progress.total_bytes)}</Table.Cell>
+                        </Table.Row>
+                        {url && <Table.Row>
+                            <Table.Cell style={{fontWeight: 600}}>URL</Table.Cell>
+                            <Table.Cell style={{wordBreak: 'break-all'}}>{url}</Table.Cell>
+                        </Table.Row>}
+                    </Table.Body>
                 </Table>
             </Modal.Content>
             <Modal.Actions>
-                <Button onClick={() => setOpen(false)}>Close</Button>
+                <Button role='cancel' onClick={() => setOpen(false)}>Close</Button>
             </Modal.Actions>
         </Modal>
     </>;
@@ -154,7 +150,7 @@ function RetryDownloadsButton({callback, selectedIds, clearSelection}) {
     const label = hasSelection ? `Retry (${selectedIds.length})` : 'Retry';
 
     return <APIButton
-        color='green'
+        role='retry'
         onClick={localRetryOnce}
         obeyWROLMode={true}
     >{label}</APIButton>
@@ -184,7 +180,7 @@ function DeleteOnceDownloadsButton({callback, selectedIds, clearSelection}) {
         : 'Are you sure you want to delete all downloads?  Some may be retried!';
 
     return <APIButton
-        color='red'
+        role='danger'
         onClick={localDeleteOnce}
         confirmContent={confirmContent}
         confirmButton='Delete'
@@ -231,24 +227,26 @@ function RecurringDownloadRow({download, fetchDownloads, onDelete}) {
     const errorModal = <Modal
         closeIcon
         onClose={handleErrorClose}
-        onOpen={handleErrorOpen}
         open={errorModalOpen}
-        trigger={<Button icon='exclamation circle' color='orange'/>}
     >
         <Modal.Header>Download Error</Modal.Header>
         <Modal.Content>
             <pre style={{overflowX: 'scroll'}}>{error}</pre>
         </Modal.Content>
         <Modal.Actions>
-            <SButton onClick={handleEditClose}>Close</SButton>
+            <Button role='cancel' onClick={handleErrorClose}>Close</Button>
         </Modal.Actions>
     </Modal>;
 
+    const errorTrigger = <IconButton icon='exclamation triangle' label='Download error' color='orange'
+                                     onClick={handleErrorOpen}/>;
+
     const hideEdit = downloader === Downloaders.MapCatalog || downloader === Downloaders.MapExtract;
-    const editButton = hideEdit ? null : <Button icon='edit' onClick={handleEditOpen}/>;
+    const editButton = hideEdit ? null :
+        <IconButton icon='edit' label='Edit download' onClick={handleEditOpen}/>;
 
     const restartButton = <APIButton
-        color='green'
+        role='retry'
         icon='redo'
         confirmContent='Are you sure you want to restart this download?'
         confirmButton='Restart'
@@ -320,24 +318,25 @@ function RecurringDownloadRow({download, fetchDownloads, onDelete}) {
         </Modal.Content>
     </Modal>;
 
-    return <TableRow>
-        <TableCell className='column-ellipsis'>
+    return <Table.Row failed={!!error && !download.progress}>
+        <Table.Cell className='column-ellipsis'>
             {link(url)}
-        </TableCell>
-        <TableCell>{formatFrequency(frequency)}</TableCell>
-        <TableCell>
+        </Table.Cell>
+        <Table.Cell>{formatFrequency(frequency)}</Table.Cell>
+        <Table.Cell>
             {last_successful_download && isoDatetimeToElapsedPopup(last_successful_download)}
-            {status === 'pending' && !download.progress && <Loader active inline size='tiny'/>}
+            {status === 'pending' && !download.progress && <Loader size='xs'/>}
             {download.progress && <DownloadProgressModal progress={download.progress} url={download.url}/>}
-        </TableCell>
-        <TableCell>{next}</TableCell>
-        <TableCell textAlign='right'>
-            {error && !download.progress && errorModal}
+        </Table.Cell>
+        <Table.Cell>{next}</Table.Cell>
+        <Table.Cell style={{textAlign: 'right'}}>
+            {error && !download.progress && errorTrigger}
             {editButton}
             {restartButton}
-        </TableCell>
+        </Table.Cell>
+        {errorModal}
         {editModal}
-    </TableRow>
+    </Table.Row>
 }
 
 function OnceDownloadRow({download, fetchDownloads, isSelected, onSelect}) {
@@ -384,35 +383,36 @@ function OnceDownloadRow({download, fetchDownloads, isSelected, onSelect}) {
         (text) => <a href={location || url} target='_blank' rel='noopener noreferrer'>{text}</a>;
 
     let completedAtCell = last_successful_download ? isoDatetimeToElapsedPopup(last_successful_download) : null;
-    let buttonCell = <TableCell/>;
+    let buttonCell = <Table.Cell/>;
     if (status === 'pending' || status === 'new') {
         buttonCell = (
-            <TableCell>
+            <Table.Cell>
                 <ButtonGroup>
                     <APIButton
-                        color='red'
-                        icon='stop circle'
+                        role='danger'
+                        icon='stop'
                         onClick={handleStop}
                         confirmContent='Are you sure you want to stop this download?  It will not be retried.'
                         confirmButton='Stop'
                         obeyWROLMode={true}
                     />
                     {status === 'new' && (downloader === Downloaders.Video || downloader === Downloaders.Archive) && (
-                        <Button
+                        <IconButton
                             icon='edit'
+                            label='Edit download'
                             color='blue'
                             onClick={handleEditOpen}
                         />
                     )}
                 </ButtonGroup>
-            </TableCell>
+            </Table.Cell>
         );
     } else if (status === 'failed' || status === 'deferred') {
         buttonCell = (
-            <TableCell>
+            <Table.Cell>
                 <ButtonGroup>
                     <APIButton
-                        color='red'
+                        role='danger'
                         icon='trash'
                         onClick={handleDelete}
                         confirmContent='Are you sure you want to delete this download?'
@@ -420,14 +420,15 @@ function OnceDownloadRow({download, fetchDownloads, isSelected, onSelect}) {
                         obeyWROLMode={true}
                     />
                     {(downloader === Downloaders.Video || downloader === Downloaders.Archive) && status !== 'pending' && (
-                        <Button
+                        <IconButton
                             icon='edit'
+                            label='Edit download'
                             color='blue'
                             onClick={handleEditOpen}
                         />
                     )}
                     <APIButton
-                        color='green'
+                        role='retry'
                         icon='redo'
                         confirmContent='Are you sure you want to restart this download?'
                         confirmButton='Start'
@@ -435,31 +436,37 @@ function OnceDownloadRow({download, fetchDownloads, isSelected, onSelect}) {
                         obeyWROLMode={true}
                     />
                 </ButtonGroup>
-            </TableCell>
+            </Table.Cell>
         );
     } else if (status === 'complete' && location) {
         buttonCell = (
-            <TableCell>
+            <Table.Cell>
                 {link('View')}
-            </TableCell>
+            </Table.Cell>
         );
     }
-    if (error && !download.progress) {
-        completedAtCell = (
-            <Modal
-                closeIcon
-                trigger={<Button icon='exclamation circle' color='red'/>}
-            >
-                <Modal.Header>Download Error</Modal.Header>
-                <Modal.Content>
-                    <pre style={{overflowX: 'scroll'}}>{error}</pre>
-                </Modal.Content>
-            </Modal>
-        )
-    }
 
     // Create edit modal for video or archive downloads
     let editModal = null;
+    let errorModal = null;
+    const [errorModalOpen, setErrorModalOpen] = React.useState(false);
+
+    if (error && !download.progress) {
+        completedAtCell = (
+            <IconButton icon='exclamation triangle' label='Download error' color='red'
+                        onClick={() => setErrorModalOpen(true)}/>
+        )
+        errorModal = <Modal
+            closeIcon
+            open={errorModalOpen}
+            onClose={() => setErrorModalOpen(false)}
+        >
+            <Modal.Header>Download Error</Modal.Header>
+            <Modal.Content>
+                <pre style={{overflowX: 'scroll'}}>{error}</pre>
+            </Modal.Content>
+        </Modal>
+    }
 
     if (downloader === Downloaders.Video) {
         editModal = (
@@ -482,7 +489,7 @@ function OnceDownloadRow({download, fetchDownloads, isSelected, onSelect}) {
                         onDelete={handleDelete}
                     />
                     {parentDownloadUrl && (
-                        <p style={{marginTop: '1em', color: '#666'}}>
+                        <p style={{marginTop: '1em', color: 'var(--muted)'}}>
                             From: <a href={parentDownloadUrl} target='_blank' rel='noopener noreferrer'>
                             {parentDownloadUrl}
                         </a>
@@ -511,7 +518,7 @@ function OnceDownloadRow({download, fetchDownloads, isSelected, onSelect}) {
                         onDelete={handleDelete}
                     />
                     {parentDownloadUrl && (
-                        <p style={{marginTop: '1em', color: '#666'}}>
+                        <p style={{marginTop: '1em', color: 'var(--muted)'}}>
                             From: <a href={parentDownloadUrl} target='_blank' rel='noopener noreferrer'>
                             {parentDownloadUrl}
                         </a>
@@ -522,24 +529,25 @@ function OnceDownloadRow({download, fetchDownloads, isSelected, onSelect}) {
         );
     }
 
-    return <TableRow>
-        <TableCell collapsing>
+    return <Table.Row failed={status === 'failed' || status === 'deferred'}>
+        <Table.Cell>
             <Checkbox
                 checked={isSelected}
                 onChange={() => onSelect(id)}
             />
-        </TableCell>
-        <TableCell className='column-ellipsis'>
+        </Table.Cell>
+        <Table.Cell className='column-ellipsis'>
             {link(url)}
-        </TableCell>
-        <TableCell>
+        </Table.Cell>
+        <Table.Cell>
             {completedAtCell}
-            {status === 'pending' && !download.progress ? <Loader active inline size='tiny'/> : null}
+            {status === 'pending' && !download.progress ? <Loader size='xs'/> : null}
             {download.progress && <DownloadProgressModal progress={download.progress} url={download.url}/>}
-        </TableCell>
+        </Table.Cell>
         {buttonCell}
+        {errorModal}
         {editModal}
-    </TableRow>
+    </Table.Row>
 }
 
 export function OnceDownloadsTable({downloads, fetchDownloads}) {
@@ -597,9 +605,9 @@ export function OnceDownloadsTable({downloads, fetchDownloads}) {
         />
     );
 
-    const footer = <TableFooter>
-        <TableRow>
-            <TableHeaderCell colSpan={4}>
+    const footer = <Table.Footer>
+        <Table.Row>
+            <Table.HeaderCell colSpan={4}>
                 <ClearDownloadsButton
                     callback={fetchDownloads}
                     selectedIds={selectedIds}
@@ -615,9 +623,9 @@ export function OnceDownloadsTable({downloads, fetchDownloads}) {
                     selectedIds={selectedIds}
                     clearSelection={clearSelection}
                 />
-            </TableHeaderCell>
-        </TableRow>
-    </TableFooter>;
+            </Table.HeaderCell>
+        </Table.Row>
+    </Table.Footer>;
 
     if (downloads && downloads.length >= 1) {
         return <SortableTable
@@ -629,29 +637,26 @@ export function OnceDownloadsTable({downloads, fetchDownloads}) {
             tableProps={{className: 'table-ellipsis'}}
         />
     } else if (downloads) {
-        return <Segment>No downloads are scheduled.</Segment>
+        return <Panel>No downloads are scheduled.</Panel>
     } else if (downloads === undefined) {
         return <ErrorMessage>Unable to fetch downloads</ErrorMessage>
     }
-    return <Placeholder>
-        <PlaceholderLine/>
-        <PlaceholderLine/>
-    </Placeholder>
+    return <Placeholder lines={2}/>
 }
 
 export function RecurringDownloadsTable({downloads, fetchDownloads, onDelete}) {
     if (downloads && downloads.length >= 1) {
-        return <Table compact className='table-ellipsis'>
-            <TableHeader>
-                <TableRow>
-                    <TableHeaderCell width={8}>URL</TableHeaderCell>
-                    <TableHeaderCell width={2}>Download Frequency</TableHeaderCell>
-                    <TableHeaderCell width={2}>Completed At</TableHeaderCell>
-                    <TableHeaderCell width={1}>Next</TableHeaderCell>
-                    <TableHeaderCell width={3} textAlign='right'>Control</TableHeaderCell>
-                </TableRow>
-            </TableHeader>
-            <TableBody>
+        return <Table className='table-ellipsis'>
+            <Table.Header>
+                <Table.Row>
+                    <Table.HeaderCell style={{width: '50%'}}>URL</Table.HeaderCell>
+                    <Table.HeaderCell style={{width: '12.5%'}}>Download Frequency</Table.HeaderCell>
+                    <Table.HeaderCell style={{width: '12.5%'}}>Completed At</Table.HeaderCell>
+                    <Table.HeaderCell style={{width: '6.25%'}}>Next</Table.HeaderCell>
+                    <Table.HeaderCell style={{width: '18.75%', textAlign: 'right'}}>Control</Table.HeaderCell>
+                </Table.Row>
+            </Table.Header>
+            <Table.Body>
                 {downloads.map(i => {
                     return <RecurringDownloadRow
                         key={i.id}
@@ -660,17 +665,14 @@ export function RecurringDownloadsTable({downloads, fetchDownloads, onDelete}) {
                         onDelete={onDelete}
                     />
                 })}
-            </TableBody>
+            </Table.Body>
         </Table>
     } else if (downloads) {
-        return <Segment>No downloads are scheduled.</Segment>
+        return <Panel>No downloads are scheduled.</Panel>
     } else if (downloads === undefined) {
         return <ErrorMessage>Unable to fetch downloads</ErrorMessage>
     }
-    return <Placeholder>
-        <PlaceholderLine/>
-        <PlaceholderLine/>
-    </Placeholder>
+    return <Placeholder lines={2}/>
 }
 
 export function DownloadsPage() {
@@ -679,7 +681,7 @@ export function DownloadsPage() {
     const {onceDownloads, recurringDownloads, pendingOnceDownloads, fetchDownloads} = useDownloads();
 
     const pendingOnceDownloadsSpan = pendingOnceDownloads > 0 ?
-        <Label color='violet' size='large'>{pendingOnceDownloads}</Label>
+        <Label color='violet'>{pendingOnceDownloads}</Label>
         : null;
 
     return <>
diff --git a/app/src/components/collections/CollectionEditForm.js b/app/src/components/collections/CollectionEditForm.js
index f0354cee..f9c4a078 100644
--- a/app/src/components/collections/CollectionEditForm.js
+++ b/app/src/components/collections/CollectionEditForm.js
@@ -47,50 +47,39 @@ export function CollectionEditForm({
 
         <form onSubmit={handleSubmit} autoComplete="off">
             {/*
-             * `ui stackable grid` replicates Semantic's own Grid CSS classes (still loaded
-             * globally via semantic-ui-offline while other call sites remain unmigrated).
-             * Callers of this component (Channels.js, Archive.js, Playlists.js) still pass
-             * Semantic <Grid.Row>/<Grid.Column> children -- they have not migrated to the
-             * component library yet. This div keeps their layout without importing
-             * semantic-ui-react here. Replace with the real `Grid`/`Grid.Col` once every
-             * caller has migrated.
-             */}
+              Every caller now passes library components rather than Semantic Grid rows, so
+              this is a plain flex column instead of the `ui stackable grid` bridge it used
+              to be.  That bridge was the last thing in the app depending on Semantic's
+              stylesheet.
+            */}
             <div
-                className="ui stackable grid"
+                className='wrolpi-form-rows'
                 style={form.loading ? {opacity: 0.6, pointerEvents: 'none'} : undefined}
             >
                 {children}
 
-                {appliedTagName && <div className="row">
-                    <div className="column">
-                        <SingleTag name={appliedTagName}/>
-                    </div>
-                </div>}
+                {appliedTagName && <div><SingleTag name={appliedTagName}/></div>}
 
-                <div className="two column row">
-                    <div className="column">
-                        {actionButtons}
-                        {onCancel && <Button
-                            type='button'
-                            role='cancel'
-                            onClick={onCancel}
-                            disabled={form.disabled}
-                            className="action-button-spacing"
-                        >
-                            Cancel
-                        </Button>}
-                    </div>
-                    <div className="column">
-                        <Button
-                            type='submit'
-                            role='save'
-                            size='lg'
-                            style={{float: 'right'}}
-                            disabled={form.disabled}
-                        >
-                            Save
-                        </Button>
-                    </div>
+                <div style={{display: 'flex', alignItems: 'center', gap: 10}}>
+                    {actionButtons}
+                    {onCancel && <Button
+                        type='button'
+                        role='cancel'
+                        onClick={onCancel}
+                        disabled={form.disabled}
+                        className="action-button-spacing"
+                    >
+                        Cancel
+                    </Button>}
+                    <Button
+                        type='submit'
+                        role='save'
+                        size='lg'
+                        style={{marginLeft: 'auto'}}
+                        disabled={form.disabled}
+                    >
+                        Save
+                    </Button>
                 </div>
             </div>
         </form>
diff --git a/app/src/components/ui/Button.tsx b/app/src/components/ui/Button.tsx
index fa46588b..de512c4a 100644
--- a/app/src/components/ui/Button.tsx
+++ b/app/src/components/ui/Button.tsx
@@ -32,6 +32,7 @@ export interface ButtonProps extends Omit<MButtonProps, 'leftSection' | 'rightSe
     type?: 'button' | 'submit' | 'reset';
     href?: string;
     target?: string;
+    component?: any;
 }
 
 const renderIcon = (icon?: string | React.ComponentType<any>) => {
@@ -69,6 +70,13 @@ export const Button = forwardRef<HTMLButtonElement, ButtonProps>((
     const fromRole = role ? roleProps[role] : undefined;
     return <MButton
         ref={ref}
+        /*
+         * An `href` makes this an anchor.  Mantine needs `component='a'` to render one, and
+         * without it the href is accepted and silently dropped — the control looks like a
+         * link and navigates nowhere.  Semantic used `as='a'` for this, so every migrated
+         * call site that carried `href` alone was quietly broken.
+         */
+        component={props.component ?? (props.href ? 'a' : undefined)}
         // An explicit color/variant still wins, so a call site can deviate when it must.
         color={props.color ?? fromRole?.color}
         variant={props.variant ?? fromRole?.variant}
@@ -88,6 +96,9 @@ export interface IconButtonProps extends Omit<ActionIconProps, 'children'> {
     label: string;
     onClick?: React.MouseEventHandler<HTMLButtonElement>;
     type?: 'button' | 'submit' | 'reset';
+    href?: string;
+    target?: string;
+    component?: any;
 }
 
 /** A square, icon-only button. */
@@ -97,6 +108,8 @@ export const IconButton = forwardRef<HTMLButtonElement, IconButtonProps>((
     const fromRole = role ? roleProps[role] : undefined;
     return <ActionIcon
         ref={ref}
+        // See Button: an href without `component='a'` renders a non-navigating button.
+        component={props.component ?? (props.href ? 'a' : undefined)}
         aria-label={label}
         title={label}
         color={props.color ?? fromRole?.color}
diff --git a/app/src/components/ui/Feedback.tsx b/app/src/components/ui/Feedback.tsx
index 2cc3b776..9ba5c043 100644
--- a/app/src/components/ui/Feedback.tsx
+++ b/app/src/components/ui/Feedback.tsx
@@ -86,6 +86,11 @@ export function Label({color = 'grey', icon, children, onClick, className}: Labe
 export interface ProgressProps {
     /** 0-100.  Values outside the range are clamped. */
     percent?: number;
+    /**
+     * Work is happening but its size is unknown — an upload that has not reported yet.
+     * Animates instead of sitting at 0%, which otherwise reads as stalled.
+     */
+    indeterminate?: boolean;
     /** Show the percentage inside the bar. */
     showPercent?: boolean;
     color?: SemanticColorName;
@@ -94,18 +99,26 @@ export interface ProgressProps {
     className?: string;
 }
 
-export function Progress({percent = 0, showPercent = true, color = 'blue', label, className}: ProgressProps) {
+export function Progress({
+    percent = 0, showPercent = true, color = 'blue', label, indeterminate, className,
+}: ProgressProps) {
     const clamped = Math.min(100, Math.max(0, Number.isFinite(percent) ? percent : 0));
     return <div
-        className={['wrolpi-progress', className].filter(Boolean).join(' ')}
+        className={['wrolpi-progress', indeterminate ? 'wrolpi-progress-indeterminate' : '', className]
+            .filter(Boolean).join(' ')}
         role='progressbar'
-        aria-valuenow={Math.round(clamped)}
+        // An indeterminate bar reports no value, which is what tells assistive tech the
+        // amount is unknown rather than zero.
+        aria-valuenow={indeterminate ? undefined : Math.round(clamped)}
         aria-valuemin={0}
         aria-valuemax={100}
     >
         <div
             className='wrolpi-progress-fill'
-            style={{width: `${clamped}%`, ['--progress-color' as string]: `var(--${color})`}}
+            style={{
+                width: indeterminate ? undefined : `${clamped}%`,
+                ['--progress-color' as string]: `var(--${color})`,
+            }}
         />
         {(showPercent || label) && <span className='wrolpi-progress-text'>
             {label ?? `${Math.round(clamped)}%`}
diff --git a/app/src/components/ui/Surfaces.tsx b/app/src/components/ui/Surfaces.tsx
index 87bef8fb..1951aa99 100644
--- a/app/src/components/ui/Surfaces.tsx
+++ b/app/src/components/ui/Surfaces.tsx
@@ -124,10 +124,17 @@ export interface CardProps {
     meta?: React.ReactNode;
     children?: React.ReactNode;
     onClick?: React.MouseEventHandler<HTMLDivElement>;
+    /**
+     * A token colour name, drawn as an accent along the card's top edge.  File cards use
+     * it to carry the mimetype's colour, so a grid of results is scannable by kind before
+     * any text is read.  It remaps per theme, so night gets a red accent rather than a
+     * dozen hues.
+     */
+    color?: string;
     className?: string;
 }
 
-export function Card({media, title, meta, children, onClick, className}: CardProps) {
+export function Card({media, title, meta, children, onClick, color, className}: CardProps) {
     return <MCard
         withBorder
         padding={0}
@@ -139,6 +146,10 @@ export function Card({media, title, meta, children, onClick, className}: CardPro
             cursor: onClick ? 'pointer' : undefined,
             display: 'flex',
             flexDirection: 'column',
+            // An accent edge rather than a tinted surface: the design rules keep surfaces
+            // flat, and a 3px edge survives night mode without becoming a bright patch.
+            // Along the bottom, where it does not compete with the poster's top edge.
+            borderBottom: color ? `3px solid var(--${color})` : undefined,
         }}
     >
         {media && <div style={{borderBottom: '1px solid var(--border)'}}>{media}</div>}
diff --git a/app/src/components/ui/ui.css b/app/src/components/ui/ui.css
index 2eb5cca7..464da8c8 100644
--- a/app/src/components/ui/ui.css
+++ b/app/src/components/ui/ui.css
@@ -342,6 +342,54 @@ html[data-theme="amber"] .wrolpi-searchbox-control:focus-within {
     border-top: 1px solid var(--border);
 }
 
+/* A stack of form rows, replacing Semantic's `ui stackable grid` in edit forms. */
+.wrolpi-form-rows {
+    display: flex;
+    flex-direction: column;
+    gap: 14px;
+}
+
+/* ------------------------------------------------------------- Form fields */
+/*
+ * `hooks/useForm.js` renders its own <label> and native <input> — it always did, with
+ * Semantic's Form.Input only wrapping them for field styling.  These rules supply that
+ * styling from tokens instead, so a native input matches the library's own controls.
+ */
+
+.wrolpi-form-field input {
+    width: 100%;
+    padding: 7px 9px;
+    background: var(--panel);
+    color: var(--text);
+    border: 1px solid var(--border);
+    font: inherit;
+    font-size: 13px;
+}
+
+.wrolpi-form-field input::placeholder {
+    color: var(--muted);
+}
+
+.wrolpi-form-field input:focus {
+    outline: none;
+    border-color: var(--blue);
+}
+
+html[data-theme="night"] .wrolpi-form-field input:focus,
+html[data-theme="amber"] .wrolpi-form-field input:focus {
+    border-color: var(--text);
+}
+
+/* An invalid field is dashed, matching every other failure state in the interface. */
+.wrolpi-form-field[data-error] input {
+    border: 1.5px dashed var(--red);
+}
+
+.wrolpi-form-field input:disabled {
+    color: var(--muted);
+    background: var(--bg);
+}
+
 /* ---------------------------------------------------------- Action inputs */
 /*
  * Input and button share one outline: the input gives up its right border and
@@ -499,6 +547,22 @@ html[data-theme="night"] .wrolpi-label {
     margin-top: 3px;
 }
 
+/*
+ * Night and amber are single-hue by definition, and a call site may legitimately want
+ * many distinguishable colours — the Flasher's chip-family badges set `--label-color`
+ * inline from a twelve-colour palette that no four tokens can express.
+ *
+ * In those themes the palette is overridden back to the theme's own text colour, so a
+ * label cannot put a green or blue pixel on a night-adapted screen.  `!important` is
+ * required because the palette arrives as an inline custom property, which a normal
+ * rule cannot outrank.  The labels stop being distinguishable by colour, which is the
+ * correct trade: the theme's whole purpose is that no other hue reaches the eye.
+ */
+html[data-theme="night"] .wrolpi-label,
+html[data-theme="amber"] .wrolpi-label {
+    --label-color: var(--text) !important;
+}
+
 /* --------------------------------------------------------------- Messages */
 
 .wrolpi-message {
@@ -581,6 +645,34 @@ html[data-theme="night"] .wrolpi-label {
     }
 }
 
+/*
+ * Indeterminate: a sliding band, for work whose size is not known yet.  Semantic called
+ * this `indicating`; without it an upload that has not reported its size sits at 0% and
+ * reads as stalled.
+ */
+.wrolpi-progress-indeterminate .wrolpi-progress-fill {
+    width: 35%;
+    animation: wrolpi-progress-slide 1.4s ease-in-out infinite;
+}
+
+@keyframes wrolpi-progress-slide {
+    from {
+        margin-left: -35%;
+    }
+    to {
+        margin-left: 100%;
+    }
+}
+
+/* Motion is the only signal here, so when it is suppressed the bar fills instead. */
+@media (prefers-reduced-motion: reduce) {
+    .wrolpi-progress-indeterminate .wrolpi-progress-fill {
+        animation: none;
+        width: 100%;
+        opacity: 0.5;
+    }
+}
+
 .wrolpi-progress-text {
     position: absolute;
     inset: 0;
diff --git a/app/src/components/ui/ui.test.js b/app/src/components/ui/ui.test.js
index 7b9fb6c0..f0cac345 100644
--- a/app/src/components/ui/ui.test.js
+++ b/app/src/components/ui/ui.test.js
@@ -11,6 +11,7 @@ import {themeChoices} from '../../themes/names';
 import {
     ActionInput,
     Button,
+    Card,
     Confirm,
     Header,
     Icon,
@@ -22,6 +23,7 @@ import {
     IconButton,
     Label,
     Message,
+    Modal,
     Panel,
     Progress,
     resolveIconName,
@@ -152,6 +154,58 @@ describe('Button', () => {
         expect(screen.getByRole('button', {name: 'New'})).toHaveAttribute('data-size', 'sm');
     });
 
+    it('renders an anchor when given an href, without being told twice', () => {
+        /*
+         * Mantine drops `href` unless it also gets `component='a'`, so a button carrying
+         * only an href looked like a link and navigated nowhere.  Semantic spelled this
+         * `as='a'`, so every migrated call site that kept just the href was silently
+         * broken — a download button that downloads nothing.
+         */
+        renderUI(<>
+            <Button href='/media/thing.pdf'>Download</Button>
+            <IconButton icon='download' label='Save file' href='/media/other.pdf'/>
+        </>);
+
+        const link = screen.getByRole('link', {name: 'Download'});
+        expect(link.tagName).toBe('A');
+        expect(link).toHaveAttribute('href', '/media/thing.pdf');
+        expect(screen.getByRole('link', {name: 'Save file'}).tagName).toBe('A');
+    });
+
+    it('forwards a ref to the underlying DOM element', () => {
+        /*
+         * Ported from the old Theme.test.js, which caught a real crash: Semantic's Button
+         * was a class component, so a forwarded ref resolved to the class instance, and
+         * anything that called `node.contains(...)` on the trigger -- a Modal or Popup
+         * portal checking whether a click landed inside -- threw "contains is not a
+         * function".  Our Tooltip and Menu targets rely on this ref too.
+         */
+        const ref = React.createRef();
+        renderUI(<Button ref={ref}>Click</Button>);
+
+        expect(ref.current).toBeInstanceOf(HTMLElement);
+        expect(typeof ref.current.contains).toBe('function');
+        expect(ref.current.tagName).toBe('BUTTON');
+    });
+
+    it('survives a document click while used as a modal trigger', () => {
+        // The other half of that regression: the Control page crashed when the document
+        // was clicked with a modal open whose trigger was a themed Button.
+        renderUI(<>
+            <Button>Open</Button>
+            <Modal open onClose={jest.fn()}><Modal.Content>content</Modal.Content></Modal>
+        </>);
+
+        expect(() => document.body.dispatchEvent(new MouseEvent('click', {bubbles: true})))
+            .not.toThrow();
+    });
+
+    it('is still a button when there is no href', () => {
+        renderUI(<Button onClick={jest.fn()}>Save</Button>);
+
+        expect(screen.getByRole('button', {name: 'Save'}).tagName).toBe('BUTTON');
+    });
+
     it('gives icon-only buttons an accessible name', () => {
         renderUI(<IconButton icon='trash' label='Delete channel'/>);
 
@@ -255,6 +309,20 @@ describe('Progress', () => {
         expect(bar).toHaveTextContent('62%');
     });
 
+    it('keeps its percent text readable on every bar colour', () => {
+        /*
+         * Ported from Theme.test.js, which asserted Semantic's `inverted-progress-text`
+         * class across all fourteen colours and both modes.  That class is gone; the
+         * mechanism now is that the text always takes `--text` while light mode lightens
+         * the fill beneath it, because the text sits across both the filled and unfilled
+         * halves of the bar.
+         */
+        const css = fs.readFileSync(path.join(__dirname, 'ui.css'), 'utf8');
+
+        expect(css).toMatch(/\.wrolpi-progress-text\s*{[^}]*color:\s*var\(--text\)/);
+        expect(css).toMatch(/html\[data-theme="light"] \.wrolpi-progress-fill\s*{[^}]*brightness/);
+    });
+
     it('clamps values outside 0-100', () => {
         // A download reporting 103% must not overflow its container.
         renderUI(<><Progress percent={150}/><Progress percent={-20}/></>);
@@ -270,6 +338,17 @@ describe('Progress', () => {
         expect(screen.getByRole('progressbar')).toHaveAttribute('aria-valuenow', '0');
     });
 
+    it('reports no value when the size is unknown', () => {
+        // Semantic called this `indicating`.  An upload that has not reported its size
+        // would otherwise sit at 0% and read as stalled, and `aria-valuenow=0` would tell
+        // a screen reader the same wrong thing.
+        renderUI(<Progress indeterminate label='Uploading…'/>);
+
+        const bar = screen.getByRole('progressbar');
+        expect(bar).not.toHaveAttribute('aria-valuenow');
+        expect(bar).toHaveClass('wrolpi-progress-indeterminate');
+    });
+
     it('shows arbitrary label text instead of the percentage', () => {
         renderUI(<Progress percent={40} label='2.1 GB / 5.3 GB'/>);
 
@@ -354,6 +433,23 @@ describe('Table', () => {
     });
 });
 
+describe('Card', () => {
+    it('draws a mimetype accent from a token, not a hex', () => {
+        // File cards carry the mimetype's colour on their top edge so a grid of results is
+        // scannable by kind.  Semantic did this with `<Card color='violet'>`; two migrated
+        // files had dropped the accent because our Card had no equivalent.
+        const {container} = renderUI(<Card title='Water Storage.pdf' color='red'/>);
+
+        expect(container.firstChild).toHaveStyle({borderBottom: '3px solid var(--red)'});
+    });
+
+    it('has no accent when no colour is given', () => {
+        const {container} = renderUI(<Card title='Plain'/>);
+
+        expect(container.firstChild.style.borderBottom).toBe('');
+    });
+});
+
 describe('Panel', () => {
     it('marks danger zones', () => {
         const {container} = renderUI(<Panel danger>Destructive actions</Panel>);
diff --git a/app/src/hooks/useForm.js b/app/src/hooks/useForm.js
index 3d6197bb..83c76718 100644
--- a/app/src/hooks/useForm.js
+++ b/app/src/hooks/useForm.js
@@ -1,8 +1,7 @@
 import React from "react";
 import _ from "lodash";
 import {InfoPopup, RequiredAsterisk, Toggle, validURL, validURLs} from "../components/Common";
-import {Form, Icon, TextArea} from "../components/Theme";
-import {Message} from "../components/ui";
+import {Icon, Message, Textarea} from "../components/ui";
 
 
 async function asyncNoOp() {
@@ -367,13 +366,14 @@ export function InputForm({
                 />
             }
         </label>
-        <Form.Input
-            id={`${name}_input`}
-            placeholder={placeholder}
-            error={inputProps.error}
-        >
-            <input {...extraInputProps} {...inputProps}/>
-        </Form.Input>
+        <div className='wrolpi-form-field' data-error={inputProps.error ? true : undefined}>
+            <input
+                id={`${name}_input`}
+                placeholder={placeholder}
+                {...extraInputProps}
+                {...inputProps}
+            />
+        </div>
         {messageElm}
     </>
 }
@@ -463,31 +463,36 @@ export function UrlsTextarea({name = 'urls', required, form}) {
     };
 
     return (
-        <Form.Input required error={inputProps.error} label="URLs">
-            <TextArea
-                id="urls_textarea"
-                placeholder="Enter one URL per line"
-                name="urls"
-                onDrop={handleDrop}
-                onKeyDown={handleKeyDown}
-                {...inputProps}
-            />
-        </Form.Input>
+        <Textarea
+            id="urls_textarea"
+            label="URLs"
+            required
+            error={inputProps.error}
+            placeholder="Enter one URL per line"
+            name="urls"
+            onDrop={handleDrop}
+            onKeyDown={handleKeyDown}
+            autosize
+            minRows={3}
+            {...inputProps}
+        />
     );
 }
 
 export function ToggleForm({form, name, label, path, icon = null, iconSize = 'big', disabled = false}) {
     const [inputProps, inputAttrs] = form.getCustomProps({name, path})
 
-    const iconElm = icon ? <Icon size={iconSize} name={icon}/> : null;
-    return <Form.Input
-        label={label}>
-        {iconElm}
-        <Toggle
-            disabled={disabled || form.disabled}
-            name={name}
-            checked={inputProps.value}
-            onChange={inputProps.onChange}
-        />
-    </Form.Input>
+    const iconElm = icon ? <Icon size={iconSize === 'big' ? 'large' : iconSize} name={icon}/> : null;
+    return <div className='wrolpi-form-field'>
+        <label><b>{label}</b></label>
+        <div style={{display: 'flex', alignItems: 'center', gap: 8}}>
+            {iconElm}
+            <Toggle
+                disabled={disabled || form.disabled}
+                name={name}
+                checked={inputProps.value}
+                onChange={inputProps.onChange}
+            />
+        </div>
+    </div>
 }
diff --git a/app/src/index.css b/app/src/index.css
index da92873c..f97b4fe3 100644
--- a/app/src/index.css
+++ b/app/src/index.css
@@ -1,8 +1,6 @@
 body {
     margin: 0;
-    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
-    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
-    sans-serif;
+    /* The font comes from the theme's `--font-body` role token; see themes/tokens.css. */
     -webkit-font-smoothing: antialiased;
     -moz-osx-font-smoothing: grayscale;
 }
diff --git a/app/src/semantic-baseline.json b/app/src/semantic-baseline.json
index 8f52ca63..fe51488c 100644
--- a/app/src/semantic-baseline.json
+++ b/app/src/semantic-baseline.json
@@ -1,17 +1 @@
-[
-  "src/components/Archive.js",
-  "src/components/BulkTagModal.js",
-  "src/components/Channels.js",
-  "src/components/Docs.js",
-  "src/components/FileBrowser.js",
-  "src/components/FilePreview.js",
-  "src/components/Flasher.js",
-  "src/components/Nav.js",
-  "src/components/Playlists.js",
-  "src/components/Theme.tsx",
-  "src/components/Upload.js",
-  "src/components/VideoPlayer.js",
-  "src/components/Zim.js",
-  "src/components/admin/ControllerPage.js",
-  "src/components/admin/Downloads.js"
-]
+[]
diff --git a/app/src/semantic-baseline.test.js b/app/src/semantic-baseline.test.js
index 1718773e..92c20ab1 100644
--- a/app/src/semantic-baseline.test.js
+++ b/app/src/semantic-baseline.test.js
@@ -13,7 +13,10 @@ import baseline from './semantic-baseline.json';
  * print 75 warnings on every dev rebuild, or fail the build outright, and CI
  * already unsets CI= for the build step so warnings there guard nothing.
  *
- * When the list reaches zero, delete this test, the JSON, and the dependencies.
+ * The list has reached zero.  The test stays as a guard rather than being deleted: it now
+ * asserts that nothing imports Semantic UI, nothing calls its toast library, nothing leans
+ * on its stylesheet, and no migrated file reaches back through Theme.tsx.  It can go when
+ * the packages themselves are uninstalled.
  */
 
 const SRC = path.join(__dirname);
@@ -74,7 +77,9 @@ describe('Semantic UI removal', () => {
          * collapse.  Anything on this list is a deliberate bridge that must be revisited
          * then; anything NOT on it is an accident.
          */
-        const allowed = ['src/components/collections/CollectionEditForm.js'];
+        // Empty, and it should stay that way: Semantic's stylesheet is no longer loaded,
+        // so a `ui ...` class name now styles nothing at all.
+        const allowed = [];
 
         const bridges = sourceFiles()
             .filter(file => !baseline.includes(file))
diff --git a/app/src/themes/tokens.css b/app/src/themes/tokens.css
index 7eaa20d2..387c67a2 100644
--- a/app/src/themes/tokens.css
+++ b/app/src/themes/tokens.css
@@ -158,12 +158,61 @@ html[data-theme="amber"] {
 /* Shell                                                                      */
 /* ------------------------------------------------------------------------- */
 
+/*
+ * Base element styling.
+ *
+ * semantic.min.css used to supply all of this, and removing it took the lot with it --
+ * links lost their colour and gained the browser's underline and visited purple, and
+ * every padded element silently changed size when `box-sizing: border-box` went away.
+ * None of it belonged to Semantic; it belongs here, expressed in tokens.
+ */
+
+html {
+    box-sizing: border-box;
+}
+
+*,
+*::before,
+*::after {
+    box-sizing: inherit;
+}
+
 body {
     background: var(--bg);
     color: var(--text);
     font-family: var(--font-body);
 }
 
+/*
+ * Links take the primary token rather than the browser's blue, and carry no underline
+ * until hovered -- a great many of them wrap cards, posters, statistics and icons, where
+ * a permanent underline is noise.  `--blue` remaps per theme, so night gets a dim red
+ * link and amber an amber one without another rule.
+ */
+a {
+    color: var(--blue);
+    text-decoration: none;
+}
+
+a:hover {
+    text-decoration: underline;
+}
+
+/* A link wrapping a card, poster or icon carries no text of its own to underline. */
+a:has(img, svg, .wrolpi-card-icon):hover {
+    text-decoration: none;
+}
+
+a:focus-visible {
+    outline: 2px solid var(--blue);
+    outline-offset: 2px;
+}
+
+html[data-theme="night"] a:focus-visible,
+html[data-theme="amber"] a:focus-visible {
+    outline-color: var(--text);
+}
+
 /* ------------------------------------------------------------------------- */
 /* Media filtering                                                            */
 /* ------------------------------------------------------------------------- */
@@ -204,6 +253,19 @@ html[data-media-filter="amber-mono"] :is(img, video, canvas, iframe, embed, obje
     filter: url(#wrolpi-amber-mono);
 }
 
+/*
+ * A `.media` wrapper filters its whole subtree as one unit, so the leaf media inside
+ * it must not be filtered a second time.  Two passes of a luminance-to-red matrix is
+ * not the same as one: the second pass takes the luminance of an already-red pixel
+ * (0.2126 of it) and the image comes out markedly darker than everything around it.
+ *
+ * The audio player's poster is the case that found this — the poster sits under
+ * custom control glyphs, so the wrapper is filtered to keep the two tinted together.
+ */
+html[data-media-filter] .media :is(img, video, canvas, iframe, embed, object) {
+    filter: none;
+}
+
 /*
  * A filter on an ancestor stops applying once the browser promotes a video to
  * native fullscreen, so the filter is restated on the fullscreened element.
diff --git a/app/src/themes/tokens.test.js b/app/src/themes/tokens.test.js
index 842ab0e9..4774bc25 100644
--- a/app/src/themes/tokens.test.js
+++ b/app/src/themes/tokens.test.js
@@ -103,7 +103,9 @@ describe('media filter rules', () => {
             .map(match => match[1]);
 
         expect(filterRules.length).toBeGreaterThan(0);
-        filterRules.forEach(selector => expect(selector).toMatch(/^data-media-filter=/));
+        // With or without a value: the reset rule for nested media keys on the bare
+        // attribute.  What matters is that no filter rule keys on `data-theme`.
+        filterRules.forEach(selector => expect(selector).toMatch(/^data-media-filter/));
     });
 
     it('has a rule for every filter a theme offers', () => {
@@ -117,6 +119,14 @@ describe('media filter rules', () => {
         });
     });
 
+    it('does not filter leaf media twice inside a filtered wrapper', () => {
+        // A `.media` wrapper filters its subtree as a unit; the img/video inside it also
+        // matches the element-type rule, and two passes of the matrix take the luminance
+        // of an already-red pixel, leaving that image much darker than its surroundings.
+        expect(tokensCss).toMatch(
+            /html\[data-media-filter] \.media :is\([^)]*\)\s*{\s*filter:\s*none/);
+    });
+
     it('never filters an ancestor, only leaf media', () => {
         // A CSS filter creates a containing block, which would break `position: fixed`
         // descendants — the nav bar and every modal.
diff --git a/app/src/types/theme.ts b/app/src/types/theme.ts
index db8a98f7..43c9c1c7 100644
--- a/app/src/types/theme.ts
+++ b/app/src/types/theme.ts
@@ -31,14 +31,6 @@ export interface StyleProps {
 
 // ThemeContext value type
 export interface ThemeContextValue {
-    /** Props for Semantic elements that support "inverted" */
-    i: InvertedProps;
-    /** Props to invert styles on elements */
-    s: StyleProps;
-    /** Props to invert text color */
-    t: StyleProps;
-    /** Class name string: 'inverted' or '' */
-    inverted: string;
     /** Current applied theme */
     theme: ThemeName;
     /** User's saved theme preference */