diff --git a/phone_app/lib/screens/day_calendar.dart b/phone_app/lib/screens/day_calendar.dart
index 5d50cdb..59965dc 100644
--- a/phone_app/lib/screens/day_calendar.dart
+++ b/phone_app/lib/screens/day_calendar.dart
@@ -1,7 +1,10 @@
 import 'package:flutter/material.dart';
+import 'package:wake_alarm_sync/screens/day_cell.dart';
 import 'package:wake_alarm_sync/services/alarm_ramp.dart';
 import 'package:wake_alarm_sync/services/free_day_pool.dart';
 
+export 'package:wake_alarm_sync/screens/day_cell.dart';
+
 /// A month grid of one day pool (free days or sick days), one tap per day.
 ///
 /// Adapted from punchme's `FreeDayCalendar` (Monday-first grid, dumb cells);
@@ -26,9 +29,14 @@ class DayCalendar extends StatelessWidget {
     this.keyPrefix = 'free-day',
     this.markColor,
     this.onMarkColor,
+    this.hasBadge,
     super.key,
   });
 
+  /// Whether a marked date carries a dot (a sick day keeping lockers);
+  /// null means never.
+  final bool Function(DateTime day)? hasBadge;
+
   /// The month on display; only its year and month are read.
   final DateTime month;
 
@@ -150,6 +158,7 @@ class DayCalendar extends StatelessWidget {
       key: ValueKey<String>('$keyPrefix-${FreeDayPool.toIso(date)}'),
       day: day,
       isMarked: isMarked(date),
+      badge: hasBadge?.call(date) ?? false,
       isWorkday: isWorkday(date),
       isPast: !open,
       markColor: markColor ?? theme.colorScheme.primary,
@@ -158,73 +167,3 @@ class DayCalendar extends StatelessWidget {
     );
   }
 }
-
-/// One day box: renders the state it is handed and reports taps.
-class DayCell extends StatelessWidget {
-  /// Creates a cell for [day] of the month.
-  const DayCell({
-    required this.day,
-    required this.isMarked,
-    required this.isWorkday,
-    required this.isPast,
-    required this.markColor,
-    required this.onMarkColor,
-    required this.onTap,
-    super.key,
-  });
-
-  /// The day of the month, as shown in the box.
-  final int day;
-
-  /// Whether this date is marked in the pool.
-  final bool isMarked;
-
-  /// A marked day's fill.
-  final Color markColor;
-
-  /// Text on [markColor].
-  final Color onMarkColor;
-
-  /// Whether this date is a weekly workday (Tue/Wed/Thu), shaded.
-  final bool isWorkday;
-
-  /// Whether this date is read-only (past, or today on the free grid).
-  final bool isPast;
-
-  /// Called on tap, or null when the cell is inert.
-  final VoidCallback? onTap;
-
-  @override
-  Widget build(BuildContext context) {
-    final colors = Theme.of(context).colorScheme;
-    // Past days keep their marker, faded: the record is history, not a
-    // choice still open.
-    final fade = isPast ? 0.38 : 1.0;
-    final background = isMarked
-        ? markColor.withValues(alpha: fade)
-        : isWorkday
-        ? colors.surfaceContainerHigh
-        : null;
-    final foreground = isMarked
-        ? onMarkColor
-        : colors.onSurface.withValues(alpha: fade);
-    return InkWell(
-      onTap: onTap,
-      borderRadius: BorderRadius.circular(8),
-      child: Container(
-        alignment: Alignment.center,
-        decoration: BoxDecoration(
-          color: background,
-          borderRadius: BorderRadius.circular(8),
-        ),
-        child: Text(
-          '$day',
-          style: TextStyle(
-            color: foreground,
-            fontWeight: isMarked ? FontWeight.w600 : FontWeight.normal,
-          ),
-        ),
-      ),
-    );
-  }
-}
diff --git a/phone_app/lib/screens/day_cell.dart b/phone_app/lib/screens/day_cell.dart
new file mode 100644
index 0000000..f35dda3
--- /dev/null
+++ b/phone_app/lib/screens/day_cell.dart
@@ -0,0 +1,88 @@
+import 'package:flutter/material.dart';
+
+Widget _dot(Color color) => Container(
+  key: const ValueKey<String>('day-badge'),
+  width: 6,
+  height: 6,
+  decoration: BoxDecoration(color: color, shape: BoxShape.circle),
+);
+
+/// One day box: renders the state it is handed and reports taps.
+class DayCell extends StatelessWidget {
+  /// Creates a cell for [day] of the month.
+  const DayCell({
+    required this.day,
+    required this.isMarked,
+    required this.isWorkday,
+    required this.isPast,
+    required this.markColor,
+    required this.onMarkColor,
+    required this.onTap,
+    this.badge = false,
+    super.key,
+  });
+
+  /// Whether a small dot sits in the corner, in [onMarkColor].
+  final bool badge;
+
+  /// The day of the month, as shown in the box.
+  final int day;
+
+  /// Whether this date is marked in the pool.
+  final bool isMarked;
+
+  /// A marked day's fill.
+  final Color markColor;
+
+  /// Text on [markColor].
+  final Color onMarkColor;
+
+  /// Whether this date is a weekly workday (Tue/Wed/Thu), shaded.
+  final bool isWorkday;
+
+  /// Whether this date is read-only (past, or today on the free grid).
+  final bool isPast;
+
+  /// Called on tap, or null when the cell is inert.
+  final VoidCallback? onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    final colors = Theme.of(context).colorScheme;
+    // Past days keep their marker, faded: the record is history, not a
+    // choice still open.
+    final fade = isPast ? 0.38 : 1.0;
+    final background = isMarked
+        ? markColor.withValues(alpha: fade)
+        : isWorkday
+        ? colors.surfaceContainerHigh
+        : null;
+    final foreground = isMarked
+        ? onMarkColor
+        : colors.onSurface.withValues(alpha: fade);
+    return InkWell(
+      onTap: onTap,
+      borderRadius: BorderRadius.circular(8),
+      child: Container(
+        alignment: Alignment.center,
+        decoration: BoxDecoration(
+          color: background,
+          borderRadius: BorderRadius.circular(8),
+        ),
+        child: Stack(
+          alignment: Alignment.center,
+          children: [
+            Text(
+              '$day',
+              style: TextStyle(
+                color: foreground,
+                fontWeight: isMarked ? FontWeight.w600 : FontWeight.normal,
+              ),
+            ),
+            if (badge) Positioned(top: 4, right: 4, child: _dot(foreground)),
+          ],
+        ),
+      ),
+    );
+  }
+}
diff --git a/phone_app/lib/screens/room_proof_screen.dart b/phone_app/lib/screens/room_proof_screen.dart
index 951ebdc..27592ab 100644
--- a/phone_app/lib/screens/room_proof_screen.dart
+++ b/phone_app/lib/screens/room_proof_screen.dart
@@ -67,7 +67,8 @@ class _RoomProofScreenState extends State<RoomProofScreen> {
       if (!mounted) return;
       setState(() {
         _scanningSlot = null;
-        _status = 'That is already tag ${slot == 0 ? 2 : 1}. Use a different '
+        _status =
+            'That is already tag ${slot == 0 ? 2 : 1}. Use a different '
             'tag, in a different room.';
       });
       return;
diff --git a/phone_app/lib/screens/sick_day_sheet.dart b/phone_app/lib/screens/sick_day_sheet.dart
new file mode 100644
index 0000000..2b30096
--- /dev/null
+++ b/phone_app/lib/screens/sick_day_sheet.dart
@@ -0,0 +1,183 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:wake_alarm_sync/services/free_day_pool.dart';
+import 'package:wake_alarm_sync/services/sick_day_keep.dart';
+import 'package:wake_alarm_sync/services/sick_day_pool.dart';
+
+/// What each locker is called on screen, in `sickdays.LOCKERS` order.
+const sickLockerLabels = <String, String>{
+  SickLocker.workout: 'Workout lock',
+  SickLocker.leetcode: 'LeetCode',
+  SickLocker.book: 'Book',
+  SickLocker.diet: 'Diet',
+  SickLocker.alarm: 'Wake alarm',
+};
+
+/// The kept lockers of a day as one line, in [sickLockerLabels] order.
+String keptLabel(Set<String> kept) => [
+  for (final MapEntry(:key, :value) in sickLockerLabels.entries)
+    if (kept.contains(key)) value,
+].join(', ');
+
+/// What the sheet was closed with.
+enum SickSheetAction {
+  /// Mark a normal day sick, keeping the switched-on lockers.
+  mark,
+
+  /// Replace a sick day's kept lockers (a keep-only edit).
+  save,
+
+  /// Clear a sick day back to normal.
+  clear,
+}
+
+/// The sheet's answer: an action and the switches as they stood.
+typedef SickSheetResult = ({SickSheetAction action, Set<String> keep});
+
+/// Why [day] cannot be marked sick for the free-day pool, or null.
+///
+/// An unopenable free-day pool ([free] null) refuses: "could not check"
+/// must never count as "not a free day".
+String? freeDayRefusal(FreeDayPool? free, DateTime day) {
+  if (free == null) {
+    return 'Free-day pool unavailable — cannot rule out a free day on '
+        '${FreeDayPool.toIso(day)}.';
+  }
+  if (!free.isFree(day)) return null;
+  return '${FreeDayPool.toIso(day)} is a free day — release it in Free '
+      'days first.';
+}
+
+/// Applies [result] to [day] in [pool]; true when anything was written.
+///
+/// A Save that changes nothing writes nothing: a fresh tick on an unchanged
+/// keep set would only churn the sync. A mark re-checks [free] through the
+/// pool (null refuses). Throws what the pool throws.
+Future<bool> applySickSheet(
+  SickDayPool pool,
+  DateTime day,
+  SickSheetResult result, {
+  required FreeDayPool? free,
+  required DateTime now,
+}) async {
+  switch (result.action) {
+    case SickSheetAction.mark:
+      final refusal = freeDayRefusal(free, day);
+      if (refusal != null) throw SickDayPolicyError(refusal);
+      await pool.add(day, isFree: free!.isFree, now: now, keep: result.keep);
+    case SickSheetAction.save:
+      if (setEquals(result.keep, pool.keptLockers(day))) return false;
+      await pool.setKept(day, result.keep, now: now);
+    case SickSheetAction.clear:
+      await pool.remove(day, now: now);
+  }
+  return true;
+}
+
+/// Opens [SickDaySheet] for [day]; null when dismissed.
+Future<SickSheetResult?> showSickDaySheet(
+  BuildContext context, {
+  required DateTime day,
+  required bool isSick,
+  required Set<String> kept,
+}) => showModalBottomSheet<SickSheetResult>(
+  context: context,
+  isScrollControlled: true,
+  showDragHandle: true,
+  builder: (_) => SickDaySheet(day: day, isSick: isSick, kept: kept),
+);
+
+/// One switch per locker for one day: on = the locker still applies,
+/// off = it stands down. A normal day opens with every switch off and a
+/// "Mark sick" confirm; a sick day opens with its current switches, "Save"
+/// (a keep-only edit) and "Clear sick day".
+class SickDaySheet extends StatefulWidget {
+  /// Creates the sheet for [day].
+  const SickDaySheet({
+    required this.day,
+    required this.isSick,
+    required this.kept,
+    super.key,
+  });
+
+  /// The date being marked or edited.
+  final DateTime day;
+
+  /// Whether [day] is already sick (edit) rather than normal (mark).
+  final bool isSick;
+
+  /// The switches to start from.
+  final Set<String> kept;
+
+  @override
+  State<SickDaySheet> createState() => _SickDaySheetState();
+}
+
+class _SickDaySheetState extends State<SickDaySheet> {
+  late final Set<String> _keep = {...widget.kept};
+
+  static const _weekdays = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'];
+
+  void _close(SickSheetAction action) => Navigator.of(
+    context,
+  ).pop<SickSheetResult>((action: action, keep: {..._keep}));
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final day = widget.day;
+    return SafeArea(
+      child: SingleChildScrollView(
+        padding: const EdgeInsets.fromLTRB(16, 0, 16, 16),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: [
+            Text(
+              '${widget.isSick ? 'Sick day' : 'Mark sick'}: '
+              '${_weekdays[day.weekday - 1]} ${FreeDayPool.toIso(day)}',
+              style: theme.textTheme.titleMedium,
+            ),
+            const SizedBox(height: 8),
+            Text(
+              'Off = stands down for the day. Switch on any locker that '
+              'should still apply; it then behaves exactly as on a normal '
+              'day.',
+              style: theme.textTheme.bodySmall?.copyWith(
+                color: theme.colorScheme.onSurfaceVariant,
+              ),
+            ),
+            const SizedBox(height: 8),
+            for (final MapEntry(:key, :value) in sickLockerLabels.entries)
+              SwitchListTile(
+                key: ValueKey<String>('keep-$key'),
+                contentPadding: EdgeInsets.zero,
+                title: Text(value),
+                value: _keep.contains(key),
+                onChanged: (on) =>
+                    setState(() => on ? _keep.add(key) : _keep.remove(key)),
+              ),
+            const SizedBox(height: 16),
+            if (widget.isSick) ...[
+              FilledButton(
+                onPressed: () => _close(SickSheetAction.save),
+                child: const Text('Save'),
+              ),
+              const SizedBox(height: 8),
+              TextButton(
+                style: TextButton.styleFrom(
+                  foregroundColor: theme.colorScheme.error,
+                ),
+                onPressed: () => _close(SickSheetAction.clear),
+                child: const Text('Clear sick day'),
+              ),
+            ] else
+              FilledButton(
+                onPressed: () => _close(SickSheetAction.mark),
+                child: const Text('Mark sick'),
+              ),
+          ],
+        ),
+      ),
+    );
+  }
+}
diff --git a/phone_app/lib/screens/sick_days_body.dart b/phone_app/lib/screens/sick_days_body.dart
index c76d6e6..25a0833 100644
--- a/phone_app/lib/screens/sick_days_body.dart
+++ b/phone_app/lib/screens/sick_days_body.dart
@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:wake_alarm_sync/screens/day_calendar.dart';
+import 'package:wake_alarm_sync/screens/sick_day_sheet.dart';
 import 'package:wake_alarm_sync/services/free_day_pool.dart';
 import 'package:wake_alarm_sync/ui/theme.dart';
 
@@ -17,9 +18,13 @@ class SickDaysBody extends StatelessWidget {
     required this.cache,
     required this.refused,
     required this.calendar,
+    required this.keptOf,
     super.key,
   });
 
+  /// The lockers a sick day keeps active, for its line in the list.
+  final Set<String> Function(DateTime day) keptOf;
+
   /// The month grid, built by the screen, which owns the displayed month.
   final DayCalendar calendar;
 
@@ -51,14 +56,17 @@ class SickDaysBody extends StatelessWidget {
         padding: const EdgeInsets.all(16),
         children: [
           Text(
-            'Tap a day to mark it sick; tap it again to clear it. Today or '
+            'Tap a day to mark it sick and choose which lockers still '
+            'apply; tap a sick day to change them or clear it. Today or '
             'later only. No limit and no reason needed.',
             style: theme.textTheme.bodyMedium,
           ),
           const SizedBox(height: 8),
           Text(
-            'On a sick day the alarm stays silent, nothing locks, and work '
-            'left undone is dropped rather than carried forward.',
+            'On a sick day every locker left off stands down: no alarm, no '
+            'lock, and work left undone is dropped rather than carried '
+            'forward. A locker switched on behaves as on a normal day; a dot '
+            'marks a sick day that keeps one.',
             style: theme.textTheme.bodySmall?.copyWith(color: muted),
           ),
           if (status.isNotEmpty) ...[
@@ -84,7 +92,14 @@ class SickDaysBody extends StatelessWidget {
           if (upcoming.isEmpty)
             Text('None ahead.', style: TextStyle(color: muted)),
           for (final day in upcoming)
-            ListTile(contentPadding: EdgeInsets.zero, title: Text(_label(day))),
+            ListTile(
+              contentPadding: EdgeInsets.zero,
+              title: Text(_label(day)),
+              subtitle: switch (keptLabel(keptOf(day))) {
+                '' => null,
+                final kept => Text('Kept: $kept'),
+              },
+            ),
         ],
       ),
     );
diff --git a/phone_app/lib/screens/sick_days_screen.dart b/phone_app/lib/screens/sick_days_screen.dart
index d3c6592..7e2f639 100644
--- a/phone_app/lib/screens/sick_days_screen.dart
+++ b/phone_app/lib/screens/sick_days_screen.dart
@@ -2,6 +2,7 @@ import 'dart:async';
 
 import 'package:flutter/material.dart';
 import 'package:wake_alarm_sync/screens/day_calendar.dart';
+import 'package:wake_alarm_sync/screens/sick_day_sheet.dart';
 import 'package:wake_alarm_sync/screens/sick_days_body.dart';
 import 'package:wake_alarm_sync/services/alarm_scheduler.dart';
 import 'package:wake_alarm_sync/services/free_day_pool.dart';
@@ -13,13 +14,15 @@ import 'package:wake_alarm_sync/ui/theme.dart';
 /// The phone's picker for the shared sick-day pool (`~/src/utils/sickdays`).
 ///
 /// Not the free-day pool, and drawn so it cannot be mistaken for it: its own
-/// name, icon and fill. Every day is normal until tapped; one tap marks a
-/// day sick, another clears it. Today and later only -- past days are
-/// inert. No cap, no reason, no confirmation.
+/// name, icon and fill. Every day is normal until marked. Tapping today or
+/// a later day opens [SickDaySheet]: one switch per locker, all off, and
+/// "Mark sick"; on a sick day, its current switches, "Save" (a keep-only
+/// edit) and "Clear sick day". Past days are inert. No cap, no reason.
 ///
-/// On a sick day every gate stands down and this phone does not ring. A
-/// free day is refused here (with the pool named), so the free-day pool is
-/// synced on open as well.
+/// On a sick day every locker left off stands down; a kept one behaves as
+/// on a normal day (the cell carries a dot). This phone does not ring only
+/// when the alarm is not kept. A free day is refused before the sheet opens
+/// (with the pool named), so the free-day pool is synced on open as well.
 class SickDaysScreen extends StatefulWidget {
   /// Creates the picker; the seams are injectable for tests.
   const SickDaysScreen({
@@ -109,11 +112,12 @@ class _SickDaysScreenState extends State<SickDaysScreen> {
     }
     if (!mounted) return;
     setState(() {
-      _cache = 'Alarm cache: ${switch (dates) {
-        null => 'unreadable',
-        [] => 'none',
-        final d => d.join(', '),
-      }}';
+      _cache =
+          'Alarm cache: ${switch (dates) {
+            null => 'unreadable',
+            [] => 'none',
+            final d => d.join(', '),
+          }}';
     });
   }
 
@@ -146,24 +150,29 @@ class _SickDaysScreenState extends State<SickDaysScreen> {
     });
   }
 
-  /// One tap per day: a sick day is cleared, any other is marked sick.
-  Future<void> _toggle(DateTime day) async {
+  /// Opens the per-locker sheet for [day] and applies what it returns.
+  Future<void> _onTapDay(DateTime day) async {
     final pool = _pool;
     if (pool == null) return;
-    final today = _today;
+    final sick = pool.isSick(day);
+    final refusal = sick ? null : freeDayRefusal(_free, day);
+    if (refusal != null) {
+      setState(() {
+        _refused = true;
+        _status = refusal;
+      });
+      return;
+    }
+    final result = await showSickDaySheet(
+      context,
+      day: day,
+      isSick: sick,
+      kept: pool.keptLockers(day),
+    );
+    if (result == null || !mounted) return;
+    final bool wrote;
     try {
-      if (pool.isSick(day)) {
-        await pool.remove(day, now: today);
-      } else {
-        final free = _free;
-        if (free == null) {
-          throw SickDayPolicyError(
-            'Free-day pool unavailable — cannot rule out a free day on '
-            '${FreeDayPool.toIso(day)}.',
-          );
-        }
-        await pool.add(day, isFree: free.isFree, now: today);
-      }
+      wrote = await applySickSheet(pool, day, result, free: _free, now: _today);
     } on SickDayPolicyError catch (e) {
       setState(() {
         _refused = true;
@@ -171,7 +180,7 @@ class _SickDaysScreenState extends State<SickDaysScreen> {
       });
       return;
     }
-    await _sync();
+    if (wrote) await _sync();
   }
 
   @override
@@ -202,6 +211,7 @@ class _SickDaysScreenState extends State<SickDaysScreen> {
                 for (final day in pool.sickDays())
                   if (!day.isBefore(_today)) day,
               ],
+              keptOf: pool.keptLockers,
               status: _status,
               cache: _cache,
               refused: _refused,
@@ -209,12 +219,13 @@ class _SickDaysScreenState extends State<SickDaysScreen> {
                 month: _month,
                 today: _today,
                 isMarked: pool.isSick,
+                hasBadge: (day) => pool.keptLockers(day).isNotEmpty,
                 busy: _busy,
                 todayTappable: true,
                 keyPrefix: 'sick-day',
                 markColor: marks.sick,
                 onMarkColor: marks.onSick,
-                onTapDay: (day) => unawaited(_toggle(day)),
+                onTapDay: (day) => unawaited(_onTapDay(day)),
                 onMonth: (month) => setState(() => _month = month),
                 // Back to January for this year's history; forward to the
                 // end of next year, the same horizon as the free days.
diff --git a/phone_app/test/sick_day_apply_test.dart b/phone_app/test/sick_day_apply_test.dart
new file mode 100644
index 0000000..7f1686b
--- /dev/null
+++ b/phone_app/test/sick_day_apply_test.dart
@@ -0,0 +1,54 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:wake_alarm_sync/screens/sick_day_sheet.dart';
+import 'package:wake_alarm_sync/services/free_day_pool.dart';
+import 'package:wake_alarm_sync/services/sick_day_pool.dart';
+
+import 'fake_day_pool_store.dart';
+
+/// `applySickSheet` on its own: the free-day check holds even when the
+/// screen's own pre-check is bypassed.
+final _today = DateTime(2026, 10, 16);
+final _day = DateTime(2026, 10, 20);
+const SickSheetResult _mark = (action: SickSheetAction.mark, keep: {'diet'});
+
+void main() {
+  late SickDayPool sick;
+  late FreeDayPool free;
+
+  setUp(() async {
+    sick = await SickDayPool.open(persistence: MemPersistence(), deviceId: 'p');
+    free = await FreeDayPool.open(persistence: MemPersistence(), deviceId: 'p');
+  });
+
+  test('a mark with no free-day pool is refused', () async {
+    await expectLater(
+      applySickSheet(sick, _day, _mark, free: null, now: _today),
+      throwsA(
+        isA<SickDayPolicyError>().having(
+          (e) => e.message,
+          'message',
+          contains('Free-day pool unavailable'),
+        ),
+      ),
+    );
+    expect(sick.isSick(_day), isFalse);
+  });
+
+  test('a mark on a free day is refused, naming the pool', () async {
+    await free.mark(_day, now: _today);
+    expect(freeDayRefusal(free, _day), contains('is a free day'));
+    await expectLater(
+      applySickSheet(sick, _day, _mark, free: free, now: _today),
+      throwsA(isA<SickDayPolicyError>()),
+    );
+  });
+
+  test('a mark keeps exactly the switched-on lockers', () async {
+    expect(
+      await applySickSheet(sick, _day, _mark, free: free, now: _today),
+      isTrue,
+    );
+    expect(sick.keptLockers(_day), {'diet'});
+    expect(keptLabel(sick.keptLockers(_day)), 'Diet');
+  });
+}
diff --git a/phone_app/test/sick_day_sheet_test.dart b/phone_app/test/sick_day_sheet_test.dart
new file mode 100644
index 0000000..bcaff96
--- /dev/null
+++ b/phone_app/test/sick_day_sheet_test.dart
@@ -0,0 +1,237 @@
+import 'package:crdt_sync/crdt_sync.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:wake_alarm_sync/screens/day_calendar.dart';
+import 'package:wake_alarm_sync/screens/sick_days_screen.dart';
+import 'package:wake_alarm_sync/services/alarm_scheduler.dart';
+import 'package:wake_alarm_sync/services/free_day_pool.dart';
+import 'package:wake_alarm_sync/services/free_day_sync.dart';
+import 'package:wake_alarm_sync/services/sick_day_keep.dart';
+import 'package:wake_alarm_sync/services/sick_day_pool.dart';
+import 'package:wake_alarm_sync/services/sick_day_sync.dart';
+import 'package:wake_alarm_sync/ui/theme.dart';
+
+import 'fake_day_pool_store.dart';
+
+/// The per-locker sheet on the sick-day calendar (sickdays 0.2.0 keep).
+final _today = DateTime(2026, 10, 16);
+final _day = DateTime(2026, 10, 20);
+bool _never(DateTime _) => false;
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  late SickDayPool sick;
+  late int syncs;
+  late List<List<String>> caches;
+
+  setUp(() async {
+    caches = [];
+    syncs = 0;
+    const channel = MethodChannel(AlarmScheduler.channelName);
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+        .setMockMethodCallHandler(channel, (call) async {
+          if (call.method == 'setSickDays') {
+            caches.add(
+              ((call.arguments as Map)['dates'] as List).cast<String>(),
+            );
+          }
+          if (call.method == 'getSickDays') {
+            return caches.isEmpty ? <String>[] : caches.last;
+          }
+          return null;
+        });
+    sick = await SickDayPool.open(
+      persistence: MemPersistence(),
+      deviceId: 'phone',
+    );
+  });
+
+  Future<void> open(WidgetTester tester) async {
+    tester.view
+      ..physicalSize = const Size(1080, 2400)
+      ..devicePixelRatio = 2.625;
+    addTearDown(tester.view.reset);
+    final scheduler = AlarmScheduler(
+      channel: const MethodChannel(AlarmScheduler.channelName),
+    );
+    final free = await FreeDayPool.open(
+      persistence: MemPersistence(),
+      deviceId: 'phone',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: buildAppTheme(),
+        home: SickDaysScreen(
+          openPool: () async => sick,
+          syncer: SickDaySync(
+            openClient: () async {
+              syncs++;
+              return null;
+            },
+            scheduler: scheduler,
+          ),
+          openFreePool: () async => free,
+          freeSyncer: FreeDaySync(
+            openClient: () async => null,
+            scheduler: scheduler,
+          ),
+          now: () => _today,
+          scheduler: scheduler,
+        ),
+      ),
+    );
+    await tester.pumpAndSettle();
+  }
+
+  Finder cell(DateTime day) =>
+      find.byKey(ValueKey<String>('sick-day-${FreeDayPool.toIso(day)}'));
+  Finder toggle(String locker) => find.byKey(ValueKey<String>('keep-$locker'));
+  bool isOn(WidgetTester tester, String locker) =>
+      tester.widget<SwitchListTile>(toggle(locker)).value;
+
+  Future<void> tap(WidgetTester tester, Finder finder) async {
+    await tester.ensureVisible(finder);
+    await tester.pumpAndSettle();
+    await tester.tap(finder);
+    await tester.pumpAndSettle();
+  }
+
+  testWidgets('a normal day opens with every locker off', (tester) async {
+    await open(tester);
+    await tap(tester, cell(_day));
+
+    expect(find.text('Mark sick: Tue 2026-10-20'), findsOneWidget);
+    for (final locker in SickLocker.all) {
+      expect(isOn(tester, locker), isFalse, reason: locker);
+    }
+    for (final label in [
+      'Workout lock',
+      'LeetCode',
+      'Book',
+      'Diet',
+      'Wake alarm',
+    ]) {
+      expect(find.text(label), findsOneWidget);
+    }
+    expect(find.text('Clear sick day'), findsNothing);
+    expect(sick.isSick(_day), isFalse, reason: 'nothing until confirmed');
+
+    await tap(tester, find.text('Mark sick'));
+    expect(sick.isSick(_day), isTrue);
+    expect(sick.keptLockers(_day), isEmpty);
+    expect(caches.last, ['2026-10-20'], reason: 'the alarm stands down');
+    expect(syncs, 2);
+  });
+
+  testWidgets('switched-on lockers are kept; a kept alarm still rings', (
+    tester,
+  ) async {
+    await open(tester);
+    await tap(tester, cell(_day));
+    await tap(tester, toggle(SickLocker.alarm));
+    await tap(tester, toggle(SickLocker.leetcode));
+    await tap(tester, find.text('Mark sick'));
+
+    expect(sick.keptLockers(_day), {SickLocker.alarm, SickLocker.leetcode});
+    expect(caches.last, isEmpty);
+    expect(find.text('Alarm cache: none'), findsOneWidget);
+    final box = tester.widget<DayCell>(cell(_day));
+    expect(box.isMarked, isTrue, reason: 'still a sick day');
+    expect(box.badge, isTrue, reason: 'kept lockers are badged');
+    expect(find.text('Kept: LeetCode, Wake alarm'), findsOneWidget);
+  });
+
+  testWidgets('a sick day without kept lockers has no badge', (tester) async {
+    await sick.add(_day, isFree: _never, now: _today);
+    await open(tester);
+    expect(tester.widget<DayCell>(cell(_day)).badge, isFalse);
+  });
+
+  testWidgets('a sick day reopens showing its switches', (tester) async {
+    await sick.add(_day, isFree: _never, now: _today, keep: ['diet']);
+    await open(tester);
+    await tap(tester, cell(_day));
+
+    expect(find.text('Sick day: Tue 2026-10-20'), findsOneWidget);
+    expect(isOn(tester, SickLocker.diet), isTrue);
+    expect(isOn(tester, SickLocker.alarm), isFalse);
+    expect(find.text('Save'), findsOneWidget);
+    expect(find.text('Clear sick day'), findsOneWidget);
+    expect(find.text('Mark sick'), findsNothing);
+  });
+
+  testWidgets('Save edits keep only, never state', (tester) async {
+    await sick.add(_day, isFree: _never, now: _today);
+    final state = sick.snapshot()['2026-10-20']!.fields['state']!;
+    await open(tester);
+    await tap(tester, cell(_day));
+    await tap(tester, toggle(SickLocker.alarm));
+    await tap(tester, find.text('Save'));
+
+    final fields = sick.snapshot()['2026-10-20']!.fields;
+    expect(fields['state'], state, reason: 'value and HLC untouched');
+    expect(fields['keep']!.$1, ['alarm']);
+    expect(fields['keep']!.$2 > state.$2, isTrue);
+    expect(caches.last, isEmpty, reason: 'the alarm now rings');
+    expect(syncs, 2);
+  });
+
+  testWidgets('Save with nothing changed writes nothing', (tester) async {
+    await sick.add(_day, isFree: _never, now: _today, keep: ['book']);
+    final before = sick.snapshot()['2026-10-20'];
+    await open(tester);
+    await tap(tester, cell(_day));
+    await tap(tester, find.text('Save'));
+    expect(sick.snapshot()['2026-10-20'], before);
+    expect(syncs, 1);
+  });
+
+  testWidgets('Clear sick day returns the day to normal', (tester) async {
+    await sick.add(_day, isFree: _never, now: _today, keep: ['alarm']);
+    await open(tester);
+    await tap(tester, cell(_day));
+    await tap(tester, find.text('Clear sick day'));
+
+    expect(sick.isSick(_day), isFalse);
+    expect(sick.snapshot()['2026-10-20']!.fields['keep']!.$1, isEmpty);
+    expect(find.text('None ahead.'), findsOneWidget);
+    expect(syncs, 2);
+  });
+
+  testWidgets('dismissing the sheet writes nothing', (tester) async {
+    await open(tester);
+    await tap(tester, cell(_day));
+    await tap(tester, toggle(SickLocker.workout));
+    await tester.tapAt(const Offset(200, 40));
+    await tester.pumpAndSettle();
+
+    expect(find.text('Mark sick'), findsNothing, reason: 'sheet closed');
+    expect(sick.isSick(_day), isFalse);
+    expect(syncs, 1);
+  });
+
+  testWidgets('a past sick day is read-only: no sheet, no edit', (
+    tester,
+  ) async {
+    final hlc = Hlc.newTick('pc');
+    await sick.replaceAll({
+      '2026-10-15': Record(
+        id: '2026-10-15',
+        fields: {
+          'state': ('sick', hlc),
+          'keep': (<Object?>['alarm'], hlc),
+        },
+      ),
+    });
+    await open(tester);
+    await tap(tester, cell(DateTime(2026, 10, 15)));
+
+    expect(find.byType(SwitchListTile), findsNothing);
+    expect(sick.keptLockers(DateTime(2026, 10, 15)), {'alarm'});
+    final box = tester.widget<DayCell>(cell(DateTime(2026, 10, 15)));
+    expect(box.isPast && box.isMarked && box.badge, isTrue);
+    expect(syncs, 1);
+  });
+}
diff --git a/phone_app/test/sick_days_screen_test.dart b/phone_app/test/sick_days_screen_test.dart
index 6fb1aa4..7065765 100644
--- a/phone_app/test/sick_days_screen_test.dart
+++ b/phone_app/test/sick_days_screen_test.dart
@@ -91,6 +91,17 @@ void main() {
     await tester.pumpAndSettle();
   }
 
+  /// Taps [day], then [button] in the per-locker sheet it opens.
+  Future<void> viaSheet(
+    WidgetTester tester,
+    DateTime day,
+    String button,
+  ) async {
+    await tapDay(tester, day);
+    await tester.tap(find.text(button));
+    await tester.pumpAndSettle();
+  }
+
   Future<void> open(WidgetTester tester, {Widget? widget}) async {
     phoneSize(tester);
     await tester.pumpWidget(widget ?? app());
@@ -110,13 +121,13 @@ void main() {
   testWidgets('today can be marked sick and cleared again', (tester) async {
     await open(tester);
 
-    await tapDay(tester, _today);
+    await viaSheet(tester, _today, 'Mark sick');
     expect(sick.isSick(_today), isTrue);
     expect(find.text('Fri 2026-10-16'), findsOneWidget);
     expect(caches.last, ['2026-10-16'], reason: 'native cache rewritten');
     expect(syncs, 2);
 
-    await tapDay(tester, _today);
+    await viaSheet(tester, _today, 'Clear sick day');
     expect(sick.isSick(_today), isFalse);
     expect(caches.last, isEmpty);
     expect(syncs, 3);
@@ -125,14 +136,12 @@ void main() {
   testWidgets('the native cache is read back after a mark', (tester) async {
     await open(tester);
     expect(find.text('Alarm cache: none'), findsOneWidget);
-    await tapDay(tester, DateTime(2026, 10, 18));
-    await tapDay(tester, DateTime(2026, 10, 17));
+    await viaSheet(tester, DateTime(2026, 10, 18), 'Mark sick');
+    await viaSheet(tester, DateTime(2026, 10, 17), 'Mark sick');
     expect(find.text('Alarm cache: 2026-10-17, 2026-10-18'), findsOneWidget);
   });
 
-  testWidgets('an unreadable native cache never reads as none', (
-    tester,
-  ) async {
+  testWidgets('an unreadable native cache never reads as none', (tester) async {
     cacheUnreadable = true;
     await open(tester);
     expect(find.text('Alarm cache: unreadable'), findsOneWidget);
@@ -140,7 +149,7 @@ void main() {
 
   testWidgets('a future day is marked in the sick colour', (tester) async {
     await open(tester);
-    await tapDay(tester, DateTime(2026, 10, 20));
+    await viaSheet(tester, DateTime(2026, 10, 20), 'Mark sick');
     expect(sick.isSick(DateTime(2026, 10, 20)), isTrue);
     final box = tester.widget<DayCell>(cell(DateTime(2026, 10, 20)));
     expect(box.markColor, DayMarkColors.dark.sick);