tidy the theme switcher popover (T-237)

Per demo feedback on the T-234 status-bar popover: collapse the -hc
theme rows into a single 'High contrast' toggle at the top (applies the
chosen base theme's -hc sibling live, falling back to the base when none
exists); list base themes only, sorted by display name; widen 240->280
and ellipsize rows so 'Catppuccin Mocha' no longer wraps; swap the swatch
dot for the Phosphor palette icon; lowercase the bar label to match the
all-lowercase status bar (proper case kept in the a11y label).

New pure theme_families helpers (base/sibling/resolve), unit-tested.
Modal picker_view consistency + the status-bar right-alignment remain on
T-237.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.pql/changelog/ticket_history/2026-06.sql

@@ -176,3 +176,4 @@ Acceptance:
 
 Implemented (2026-06-03): pure grouping in activity_cluster.dart (groupConversation + FoldLevel none/tools/thinking/everything + RenderGroup StickyItem/FoldedCluster), fully unit-tested. Activity card + grouping wired into conversation_view.dart (collapsed live ticker of the latest step + step count; click/Enter expands to the folded steps in order; Semantics announces count + expanded/collapsed). Default level = L1 (tools): tool calls+results fold; user/Claude prose, FAILED results (sticky, surfaced), diffs (Edit/Write), and thinking stay first-class. Added FoldLevel.none (no folding) used by the existing item-level renderer tests. DEFERRED (acceptance 4''s persistence): the fold level is a switchable ConversationView parameter (proven by tests; none/L1/L2/L3 re-group) but is NOT yet wired to a persisted user setting + a UI control — the live pane uses the L1 default. Follow-up: read it from settings (ctx.settings) + a control to change it. Did NOT match the wireframe pixel-for-pixel; functional shape per the refinement decisions.', NULL, '2026-06-03 15:17:10', '2026-06-03 15:17:10', '2026-06-03 15:17:10', NULL, 'be73ea1e861930fc12fd9d6050cc6841', 1) ON CONFLICT(hash) DO NOTHING;
 INSERT INTO ticket_history (ticket_id, field, old_value, new_value, changed_by, changed_at, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('T-230', 'status', 'in_progress', 'done', NULL, '2026-06-03 15:17:33', '2026-06-03 15:17:33', '2026-06-03 15:17:33', NULL, '069a613ac7439a5d19da505712da8341', 1) ON CONFLICT(hash) DO NOTHING;
+INSERT INTO ticket_history (ticket_id, field, old_value, new_value, changed_by, changed_at, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('T-237', 'status', 'backlog', 'in_progress', NULL, '2026-06-03 15:43:55', '2026-06-03 15:43:55', '2026-06-03 15:43:55', NULL, '8505c7a515c60be219fdaafd5c0c4acc', 1) ON CONFLICT(hash) DO NOTHING;

.pql/changelog/tickets/2026-06.sql

@@ -446,3 +446,23 @@ Acceptance:
 6. Keyboard + screen-reader accessible (expand/collapse, step count announced).
 
 Implemented (2026-06-03): pure grouping in activity_cluster.dart (groupConversation + FoldLevel none/tools/thinking/everything + RenderGroup StickyItem/FoldedCluster), fully unit-tested. Activity card + grouping wired into conversation_view.dart (collapsed live ticker of the latest step + step count; click/Enter expands to the folded steps in order; Semantics announces count + expanded/collapsed). Default level = L1 (tools): tool calls+results fold; user/Claude prose, FAILED results (sticky, surfaced), diffs (Edit/Write), and thinking stay first-class. Added FoldLevel.none (no folding) used by the existing item-level renderer tests. DEFERRED (acceptance 4''s persistence): the fold level is a switchable ConversationView parameter (proven by tests; none/L1/L2/L3 re-group) but is NOT yet wired to a persisted user setting + a UI control — the live pane uses the L1 default. Follow-up: read it from settings (ctx.settings) + a control to change it. Did NOT match the wireframe pixel-for-pixel; functional shape per the refinement decisions.', 'done', 'medium', NULL, NULL, NULL, '2026-06-03 11:15:39', '2026-06-03 15:17:33', NULL, '2f9702465f4d0079bca7f4f4e7b60095', 1) ON CONFLICT(id) DO UPDATE SET type=excluded.type, parent_id=excluded.parent_id, title=excluded.title, description=excluded.description, status=excluded.status, priority=excluded.priority, assigned_to=excluded.assigned_to, team=excluded.team, decision_ref=excluded.decision_ref, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > tickets.updated_at OR (excluded.updated_at = tickets.updated_at AND excluded.hash > tickets.hash);
+INSERT INTO tickets (id, type, parent_id, title, description, status, priority, assigned_to, team, decision_ref, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('T-236', 'story', 'T-132', 'Render pasted-image @path tokens as thumbnails in the message log', 'When a user message contains a pasted-screenshot reference — an @<path> token pointing at an image (the composer''s ComposerAttachment.pathToken format, e.g. @/home/<user>/.cache/clide/pasted/paste-<ts>.png, see screenshot) — the conversation log renders it as the raw path string. Show it as an inline THUMBNAIL instead.
+
+The composer already renders pre-send attachments as Image.file thumbnail chips (clipboard_paste.dart + claude_composer _chip); this carries that into the post-send message log (UserMessage rendering in conversation_view/conversation_card).
+
+Scope:
+- When rendering UserMessage text, detect @<path> tokens; for image paths (reuse the extension check behind _looksLikeImage: .png/.jpg/.jpeg/.gif/.webp/.bmp), render a bounded Image.file thumbnail in place of the bare token. Surrounding prose still renders normally; a message can carry multiple tokens.
+- Click/activate the thumbnail to open the full-size image (a preview dialog). Keyboard-operable + a11y label (filename).
+- Graceful fallback: a missing/unreadable file (pasted temp files can be cleaned up) degrades to a small placeholder or the path text via Image.file errorBuilder — never a crash/exception.
+- Non-image @path tokens MAY render as a file chip (filename + icon) like the composer, but image thumbnails are the focus.
+- Note: Image.file reads the path directly via dart:io, so this is NOT gated by the files.read allow-list (D-80) — the cache dir is outside the workspace and that''s fine for display.
+- Display-only: the text actually sent to Claude is unchanged; this only affects rendering.
+
+Acceptance:
+1. A user message with an @<path> image token shows an inline thumbnail in the log (not the raw path).
+2. Clicking/activating the thumbnail opens the full image.
+3. A missing/unreadable referenced file degrades to a placeholder (or the path text), no exception.
+4. Prose and any non-image @path tokens around it still render readably; multiple tokens in one message all resolve.
+5. The message content delivered to Claude is unchanged (render-only). Relates to T-142 (paste attachments).', 'backlog', 'medium', NULL, NULL, NULL, '2026-06-03 15:31:01', '2026-06-03 15:31:01', NULL, '6cf569924ec0dbc31a4b2711aa420be2', 1) ON CONFLICT(id) DO UPDATE SET type=excluded.type, parent_id=excluded.parent_id, title=excluded.title, description=excluded.description, status=excluded.status, priority=excluded.priority, assigned_to=excluded.assigned_to, team=excluded.team, decision_ref=excluded.decision_ref, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > tickets.updated_at OR (excluded.updated_at = tickets.updated_at AND excluded.hash > tickets.hash);
+INSERT INTO tickets (id, type, parent_id, title, description, status, priority, assigned_to, team, decision_ref, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('T-237', 'task', NULL, 'Theme picker polish: collapse -hc into a checkbox, sort, widen, palette icon', 'User feedback on the T-234 status-bar theme popover (screenshot 2026-06-03): (1) the menu order looks random — the -hc variants are interleaved. (2) Hide all the high-contrast theme entries and replace them with a single ''[ ] High contrast'' checkbox at the top; toggling it applies the -hc sibling of the chosen base theme. (3) Widen the popover so long names (''Catppuccin Mocha'') don''t wrap; rows ellipsize. (4) The status-bar items (''application ok'' + theme switcher) float in the middle (boxed into the workspace column between the per-column bottom rails) instead of hugging the window''s right edge — align them right. (5) Replace the swatch dot on the trigger with a Phosphor icon (palette, 0xe6c8, already in the registry — paint-roller has no registered codepoint). Apply the -hc-as-checkbox + sort to the modal picker_view too for consistency. Helpers: base = name without -hc/-cb; show base themes only; resolve(base, hc) -> base+''-hc'' if it exists.', 'backlog', 'medium', NULL, NULL, 'D-6', '2026-06-03 15:43:45', '2026-06-03 15:43:45', NULL, '411a82da35f5bad2611cf4f4ff38aa13', 1) ON CONFLICT(id) DO UPDATE SET type=excluded.type, parent_id=excluded.parent_id, title=excluded.title, description=excluded.description, status=excluded.status, priority=excluded.priority, assigned_to=excluded.assigned_to, team=excluded.team, decision_ref=excluded.decision_ref, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > tickets.updated_at OR (excluded.updated_at = tickets.updated_at AND excluded.hash > tickets.hash);
+INSERT INTO tickets (id, type, parent_id, title, description, status, priority, assigned_to, team, decision_ref, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('T-237', 'task', NULL, 'Theme picker polish: collapse -hc into a checkbox, sort, widen, palette icon', 'User feedback on the T-234 status-bar theme popover (screenshot 2026-06-03): (1) the menu order looks random — the -hc variants are interleaved. (2) Hide all the high-contrast theme entries and replace them with a single ''[ ] High contrast'' checkbox at the top; toggling it applies the -hc sibling of the chosen base theme. (3) Widen the popover so long names (''Catppuccin Mocha'') don''t wrap; rows ellipsize. (4) The status-bar items (''application ok'' + theme switcher) float in the middle (boxed into the workspace column between the per-column bottom rails) instead of hugging the window''s right edge — align them right. (5) Replace the swatch dot on the trigger with a Phosphor icon (palette, 0xe6c8, already in the registry — paint-roller has no registered codepoint). Apply the -hc-as-checkbox + sort to the modal picker_view too for consistency. Helpers: base = name without -hc/-cb; show base themes only; resolve(base, hc) -> base+''-hc'' if it exists.', 'in_progress', 'medium', NULL, NULL, 'D-6', '2026-06-03 15:43:45', '2026-06-03 15:43:55', NULL, 'fc2bc3d466dbae36975e79cabcf289ee', 1) ON CONFLICT(id) DO UPDATE SET type=excluded.type, parent_id=excluded.parent_id, title=excluded.title, description=excluded.description, status=excluded.status, priority=excluded.priority, assigned_to=excluded.assigned_to, team=excluded.team, decision_ref=excluded.decision_ref, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > tickets.updated_at OR (excluded.updated_at = tickets.updated_at AND excluded.hash > tickets.hash);

lib/builtin/theme_picker/src/theme_families.dart

@@ -0,0 +1,29 @@
+/// Theme-family helpers for the picker surfaces (T-237).
+///
+/// Bundled themes ship as a base + a high-contrast (`-hc`) / colour-blind
+/// (`-cb`) sibling (D-69). The pickers don't list the siblings as separate
+/// rows — they show base themes only and expose the variant as a "High
+/// contrast" toggle. These pure helpers do the base/sibling bookkeeping so
+/// the popover and the modal share one source of truth.
+library;
+
+import 'package:clide/kernel/kernel.dart' show ThemeDefinition;
+
+bool isHcName(String name) => name.endsWith('-hc');
+bool isCbName(String name) => name.endsWith('-cb');
+
+/// The base theme name for any theme (strips a `-hc`/`-cb` suffix).
+String baseThemeName(String name) => (isHcName(name) || isCbName(name)) ? name.substring(0, name.length - 3) : name;
+
+/// Base themes only (no `-hc`/`-cb`), sorted by display name so the list is
+/// stable and not "randomly" ordered.
+List<ThemeDefinition> baseThemes(List<ThemeDefinition> available) =>
+    available.where((t) => !isHcName(t.name) && !isCbName(t.name)).toList()..sort((a, b) => a.displayName.toLowerCase().compareTo(b.displayName.toLowerCase()));
+
+/// Whether [base] has a high-contrast sibling among [available].
+bool hasHcSibling(List<ThemeDefinition> available, String base) => available.any((t) => t.name == '$base-hc');
+
+/// The theme name to actually apply for a chosen [base] given the high-contrast
+/// toggle: the `-hc` sibling when requested and present, else the base itself.
+String resolveThemeName(List<ThemeDefinition> available, String base, {required bool highContrast}) =>
+    (highContrast && hasHcSibling(available, base)) ? '$base-hc' : base;

lib/builtin/theme_picker/src/theme_status_item.dart

@@ -5,6 +5,7 @@
 /// (D-6 parity — both reach the same ThemeController).
 library;
 
+import 'package:clide/builtin/theme_picker/src/theme_families.dart';
 import 'package:clide/kernel/kernel.dart';
 import 'package:clide/widgets/widgets.dart';
 import 'package:flutter/widgets.dart';
@@ -60,11 +61,7 @@ class _ThemeSwitcherStatusItemState extends State<ThemeSwitcherStatusItem> {
               bottom: screen.height - anchor.dy + 4,
               child: _ThemePopover(
                 controller: _controller,
-                onPick: (name) {
+                onClose: _close,
-                  _controller.select(name);
-                  _close();
-                },
-                onDismiss: _close,
               ),
             ),
           ],
@@ -103,14 +100,11 @@ class _ThemeSwitcherStatusItemState extends State<ThemeSwitcherStatusItem> {
               child: Row(
                 mainAxisSize: MainAxisSize.min,
                 children: [
-                  // A swatch dot in the theme's accent — the "what theme" cue.
+                  ClideIcon(PhosphorIcons.palette, size: 13, color: tokens.statusBarForeground),
-                  Container(
-                    width: 8,
-                    height: 8,
-                    decoration: BoxDecoration(color: tokens.buttonBackground, shape: BoxShape.circle),
-                  ),
                   const SizedBox(width: 6),
-                  ClideText(label, fontSize: clideFontCaption, color: tokens.statusBarForeground),
+                  // The status bar is all-lowercase; the proper-case name stays
+                  // in the Semantics label for screen readers.
+                  ClideText(label.toLowerCase(), fontSize: clideFontCaption, color: tokens.statusBarForeground),
                 ],
               ),
             ),
@@ -121,14 +115,15 @@ class _ThemeSwitcherStatusItemState extends State<ThemeSwitcherStatusItem> {
   }
 }
 
-/// The popover body: a keyboard-navigable list of themes. Autofocuses so
+/// The popover body: a "High contrast" toggle then the base themes (the `-hc`
-/// arrows/Enter/Esc work immediately; the current theme starts highlighted.
+/// siblings collapse into the toggle, T-237). Keyboard-navigable as one list —
+/// index 0 is the toggle, 1..N the themes; arrows move, Enter activates, Esc
+/// dismisses. Autofocuses on open.
 class _ThemePopover extends StatefulWidget {
-  const _ThemePopover({required this.controller, required this.onPick, required this.onDismiss});
+  const _ThemePopover({required this.controller, required this.onClose});
 
   final ThemeController controller;
-  final void Function(String name) onPick;
+  final VoidCallback onClose;
-  final VoidCallback onDismiss;
 
   @override
   State<_ThemePopover> createState() => _ThemePopoverState();
@@ -136,14 +131,18 @@ class _ThemePopover extends StatefulWidget {
 
 class _ThemePopoverState extends State<_ThemePopover> {
   final _focus = FocusNode(debugLabel: 'ThemeSwitcher.popover');
-  late int _index;
+  late bool _hc;
+  int _index = 0;
+
+  List<ThemeDefinition> get _themes => baseThemes(widget.controller.available);
 
   @override
   void initState() {
     super.initState();
-    final themes = widget.controller.available;
+    _hc = isHcName(widget.controller.currentName);
-    _index = themes.indexWhere((t) => t.name == widget.controller.currentName);
+    final currentBase = baseThemeName(widget.controller.currentName);
-    if (_index < 0) _index = 0;
+    final at = _themes.indexWhere((t) => t.name == currentBase);
+    _index = at < 0 ? 0 : at + 1; // +1: row 0 is the toggle
     WidgetsBinding.instance.addPostFrameCallback((_) => _focus.requestFocus());
   }
 
@@ -153,22 +152,38 @@ class _ThemePopoverState extends State<_ThemePopover> {
     super.dispose();
   }
 
+  void _toggleHc() {
+    setState(() => _hc = !_hc);
+    // Re-apply the current base with the new variant, live; keep the popover open.
+    final base = baseThemeName(widget.controller.currentName);
+    widget.controller.select(resolveThemeName(widget.controller.available, base, highContrast: _hc));
+  }
+
+  void _pick(ThemeDefinition base) {
+    widget.controller.select(resolveThemeName(widget.controller.available, base.name, highContrast: _hc));
+    widget.onClose();
+  }
+
   KeyEventResult _onKey(FocusNode node, KeyEvent event) {
     if (event is! KeyDownEvent && event is! KeyRepeatEvent) return KeyEventResult.ignored;
-    final themes = widget.controller.available;
+    final count = _themes.length + 1; // +1 toggle
     switch (event.logicalKey) {
       case LogicalKeyboardKey.arrowDown:
-        setState(() => _index = (_index + 1) % themes.length);
+        setState(() => _index = (_index + 1) % count);
         return KeyEventResult.handled;
       case LogicalKeyboardKey.arrowUp:
-        setState(() => _index = (_index - 1 + themes.length) % themes.length);
+        setState(() => _index = (_index - 1 + count) % count);
         return KeyEventResult.handled;
       case LogicalKeyboardKey.enter:
       case LogicalKeyboardKey.numpadEnter:
-        widget.onPick(themes[_index].name);
+        if (_index == 0) {
+          _toggleHc();
+        } else {
+          _pick(_themes[_index - 1]);
+        }
         return KeyEventResult.handled;
       case LogicalKeyboardKey.escape:
-        widget.onDismiss();
+        widget.onClose();
         return KeyEventResult.handled;
     }
     return KeyEventResult.ignored;
@@ -177,8 +192,8 @@ class _ThemePopoverState extends State<_ThemePopover> {
   @override
   Widget build(BuildContext context) {
     final tokens = ClideTheme.of(context).surface;
-    final themes = widget.controller.available;
+    final themes = _themes;
-    final currentName = widget.controller.currentName;
+    final currentBase = baseThemeName(widget.controller.currentName);
     return Focus(
       focusNode: _focus,
       onKeyEvent: _onKey,
@@ -187,25 +202,32 @@ class _ThemePopoverState extends State<_ThemePopover> {
         label: 'Theme switcher',
         explicitChildNodes: true,
         child: ClideSurface(
-          width: 240,
+          width: 280,
           color: tokens.modalSurfaceBackground,
           border: tokens.modalSurfaceBorder,
           padding: const EdgeInsets.all(4),
           borderRadius: BorderRadius.circular(4),
           child: ConstrainedBox(
-            constraints: const BoxConstraints(maxHeight: 320),
+            constraints: const BoxConstraints(maxHeight: 360),
             child: SingleChildScrollView(
               child: Column(
                 mainAxisSize: MainAxisSize.min,
                 crossAxisAlignment: CrossAxisAlignment.stretch,
                 children: [
+                  _HighContrastToggle(
+                    checked: _hc,
+                    highlighted: _index == 0,
+                    onEnter: () => setState(() => _index = 0),
+                    onTap: _toggleHc,
+                  ),
+                  ClideDivider(),
                   for (var i = 0; i < themes.length; i++)
                     _PopoverRow(
                       displayName: themes[i].displayName,
-                      selected: themes[i].name == currentName,
+                      selected: themes[i].name == currentBase,
-                      highlighted: i == _index,
+                      highlighted: _index == i + 1,
-                      onEnter: () => setState(() => _index = i),
+                      onEnter: () => setState(() => _index = i + 1),
-                      onTap: () => widget.onPick(themes[i].name),
+                      onTap: () => _pick(themes[i]),
                     ),
                 ],
               ),
@@ -217,6 +239,53 @@ class _ThemePopoverState extends State<_ThemePopover> {
   }
 }
 
+/// The "High contrast" checkbox row at the top of the popover.
+class _HighContrastToggle extends StatelessWidget {
+  const _HighContrastToggle({required this.checked, required this.highlighted, required this.onEnter, required this.onTap});
+
+  final bool checked;
+  final bool highlighted;
+  final VoidCallback onEnter;
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    final tokens = ClideTheme.of(context).surface;
+    return Semantics(
+      checked: checked,
+      label: 'High contrast',
+      excludeSemantics: true,
+      child: MouseRegion(
+        cursor: SystemMouseCursors.click,
+        onEnter: (_) => onEnter(),
+        child: GestureDetector(
+          onTap: onTap,
+          child: Container(
+            color: highlighted ? tokens.listItemHoverBackground : tokens.listItemBackground,
+            padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 6),
+            child: Row(
+              children: [
+                Container(
+                  width: 13,
+                  height: 13,
+                  decoration: BoxDecoration(
+                    color: checked ? tokens.buttonBackground : null,
+                    border: Border.all(color: checked ? tokens.buttonBackground : tokens.modalSurfaceBorder),
+                    borderRadius: BorderRadius.circular(3),
+                  ),
+                  child: checked ? ClideIcon(const CheckIcon(), size: 9, color: tokens.buttonForeground) : null,
+                ),
+                const SizedBox(width: 8),
+                Expanded(child: ClideText('High contrast', color: tokens.listItemForeground, fontSize: clideFontCaption)),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}
+
 class _PopoverRow extends StatelessWidget {
   const _PopoverRow({
     required this.displayName,
@@ -259,7 +328,7 @@ class _PopoverRow extends StatelessWidget {
                   )
                 else
                   const SizedBox(width: 17),
-                Expanded(child: ClideText(displayName, color: fg, fontSize: clideFontCaption)),
+                Expanded(child: ClideText(displayName, color: fg, fontSize: clideFontCaption, maxLines: 1, overflow: TextOverflow.ellipsis)),
               ],
             ),
           ),

test/builtin/theme_picker/theme_families_test.dart

@@ -0,0 +1,43 @@
+/// Tests for the theme-family helpers (T-237).
+library;
+
+import 'package:clide/builtin/theme_picker/src/theme_families.dart';
+import 'package:clide/kernel/kernel.dart';
+import 'package:test/test.dart';
+
+ThemeDefinition _def(String name, String display) => ThemeDefinition(name: name, displayName: display, dark: true, palette: Palette(const {}));
+
+void main() {
+  final all = [
+    _def('clide', 'Clide'),
+    _def('clide-hc', 'Clide (high contrast)'),
+    _def('midnight', 'Midnight'),
+    _def('midnight-hc', 'Midnight (high contrast)'),
+    _def('catppuccin-mocha', 'Catppuccin Mocha'),
+    _def('catppuccin-mocha-hc', 'Catppuccin Mocha (high contrast)'),
+    _def('paper', 'Paper'), // no -hc sibling in this fixture
+  ];
+
+  test('isHcName / baseThemeName', () {
+    expect(isHcName('midnight-hc'), isTrue);
+    expect(isHcName('midnight'), isFalse);
+    expect(baseThemeName('midnight-hc'), 'midnight');
+    expect(baseThemeName('catppuccin-mocha-hc'), 'catppuccin-mocha');
+    expect(baseThemeName('clide'), 'clide');
+  });
+
+  test('baseThemes drops -hc/-cb and sorts by display name', () {
+    final bases = baseThemes(all).map((t) => t.name).toList();
+    expect(bases, ['catppuccin-mocha', 'clide', 'midnight', 'paper']); // alphabetical by display
+    expect(bases.any(isHcName), isFalse);
+  });
+
+  test('hasHcSibling + resolveThemeName', () {
+    expect(hasHcSibling(all, 'midnight'), isTrue);
+    expect(hasHcSibling(all, 'paper'), isFalse);
+    expect(resolveThemeName(all, 'midnight', highContrast: true), 'midnight-hc');
+    expect(resolveThemeName(all, 'midnight', highContrast: false), 'midnight');
+    // No sibling → falls back to the base even when high contrast is on.
+    expect(resolveThemeName(all, 'paper', highContrast: true), 'paper');
+  });
+}

test/builtin/theme_picker/widget_test.dart

@@ -140,6 +140,23 @@ void main() {
       expect(find.bySemanticsLabel('forest'), findsNothing);
     });
 
+    testWidgets('popover hides -hc rows; the High contrast toggle applies the sibling (T-237)', (tester) async {
+      final f2 = await KernelFixture.create(bundledThemes: [_def('midnight'), _def('midnight-hc')]);
+      addTearDown(f2.dispose);
+      await tester.pumpWidget(harness(f2, const ThemeSwitcherStatusItem()));
+      await tester.pump();
+      await tester.tap(find.bySemanticsLabel('Theme: midnight'));
+      await tester.pumpAndSettle();
+      // Base shown, -hc row hidden, toggle present.
+      expect(find.text('midnight'), findsOneWidget);
+      expect(find.text('midnight-hc'), findsNothing);
+      expect(find.text('High contrast'), findsOneWidget);
+      // Toggling high contrast applies the -hc sibling live.
+      await tester.tap(find.bySemanticsLabel('High contrast'));
+      await tester.pumpAndSettle();
+      expect(f2.services.theme.currentName, 'midnight-hc');
+    });
+
     testWidgets('Esc dismisses the popover without changing the theme (T-234)', (tester) async {
       await tester.pumpWidget(harness(f, const ThemeSwitcherStatusItem()));
       await tester.pump();