feat: P5-21 mention color, P5-22 font selector, P5-27 notification presets; update docs

- P5-21: Custom @mention highlight color picker in Settings → Appearance.
  CSS vars with luminance-computed text color; resets cleanly to theme default.
- P5-22: Font selector (System, Inter, JetBrains Mono, Fira Code) in
  Settings → Appearance. Fira Code added to Google Fonts preload.
- P5-27: Gaming/Work/Sleep preset buttons at top of Settings → Notifications.
  Each atomically applies a group of notification settings.
- AppearanceEffects component in App.tsx applies CSS vars on settings change.
- LOTUS_BUGS.md: mark presence + manifest icon bugs as resolved.
- LOTUS_TODO.md: mark P3-6, P5-21, P5-22, P5-27 as [x].
- LOTUS_FEATURES.md: document all four completed features.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/features/settings/general/General.tsx

@@ -333,6 +333,11 @@ function Appearance() {
     'glassmorphismSidebar',
   );
   const [pauseAnimations, setPauseAnimations] = useSetting(settingsAtom, 'pauseAnimations');
+  const [mentionHighlightColor, setMentionHighlightColor] = useSetting(
+    settingsAtom,
+    'mentionHighlightColor',
+  );
+  const [fontFamily, setFontFamily] = useSetting(settingsAtom, 'fontFamily');
 
   return (
     <Box direction="Column" gap="100">
@@ -494,6 +499,69 @@ function Appearance() {
           }
         />
       </SequenceCard>
+      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column">
+        <SettingTile
+          title="UI Font"
+          description="Font used throughout the interface."
+          after={
+            <select
+              value={fontFamily ?? 'inter'}
+              onChange={(e) =>
+                setFontFamily(
+                  e.target.value as 'system' | 'inter' | 'jetbrains-mono' | 'fira-code',
+                )
+              }
+              style={{
+                background: 'var(--bg-surface)',
+                color: 'inherit',
+                border: '1px solid var(--border-interactive-normal)',
+                borderRadius: '6px',
+                padding: '4px 8px',
+                fontSize: '14px',
+                cursor: 'pointer',
+              }}
+            >
+              <option value="system">System Default</option>
+              <option value="inter">Inter (default)</option>
+              <option value="jetbrains-mono">JetBrains Mono</option>
+              <option value="fira-code">Fira Code</option>
+            </select>
+          }
+        />
+      </SequenceCard>
+      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column">
+        <SettingTile
+          title="@Mention Highlight Color"
+          description="Color used to highlight messages that mention you. Leave empty to use the theme default."
+          after={
+            <Box alignItems="Center" gap="200">
+              <input
+                type="color"
+                value={mentionHighlightColor || '#4caf50'}
+                onChange={(e) => setMentionHighlightColor(e.target.value)}
+                style={{ width: '36px', height: '28px', cursor: 'pointer', borderRadius: '4px', border: 'none', padding: '2px' }}
+              />
+              {mentionHighlightColor && (
+                <button
+                  type="button"
+                  onClick={() => setMentionHighlightColor('')}
+                  style={{
+                    background: 'none',
+                    border: '1px solid var(--border-interactive-normal)',
+                    borderRadius: '6px',
+                    padding: '2px 8px',
+                    cursor: 'pointer',
+                    color: 'inherit',
+                    fontSize: '12px',
+                  }}
+                >
+                  Reset
+                </button>
+              )}
+            </Box>
+          }
+        />
+      </SequenceCard>
     </Box>
   );
 }

src/app/features/settings/notifications/Notifications.tsx

@@ -1,5 +1,6 @@
 import React from 'react';
-import { Box, Text, IconButton, Icon, Icons, Scroll } from 'folds';
+import { useAtomValue, useSetAtom } from 'jotai';
+import { Box, Text, IconButton, Icon, Icons, Scroll, config, toRem } from 'folds';
 import { Page, PageContent, PageHeader } from '../../../components/page';
 import { SystemNotification } from './SystemNotification';
 import { AllMessagesNotifications } from './AllMessages';
@@ -9,6 +10,95 @@ import { PushRuleEditor } from './PushRuleEditor';
 import { SequenceCard } from '../../../components/sequence-card';
 import { SequenceCardStyle } from '../styles.css';
 import { SettingTile } from '../../../components/setting-tile';
+import { settingsAtom, Settings } from '../../../state/settings';
+
+const PRESETS: Array<{
+  label: string;
+  emoji: string;
+  description: string;
+  patch: Partial<Settings>;
+}> = [
+  {
+    label: 'Gaming',
+    emoji: '🎮',
+    description: 'Notifications on, sounds off',
+    patch: {
+      showNotifications: true,
+      isNotificationSounds: false,
+      messageSoundId: 'none',
+      inviteSoundId: 'none',
+      quietHoursEnabled: false,
+    },
+  },
+  {
+    label: 'Work',
+    emoji: '💼',
+    description: 'All notifications and sounds on',
+    patch: {
+      showNotifications: true,
+      isNotificationSounds: true,
+      messageSoundId: 'notification',
+      inviteSoundId: 'invite',
+      quietHoursEnabled: false,
+    },
+  },
+  {
+    label: 'Sleep',
+    emoji: '🌙',
+    description: 'All notifications off',
+    patch: {
+      showNotifications: false,
+      isNotificationSounds: false,
+      quietHoursEnabled: false,
+    },
+  },
+];
+
+function NotificationPresets() {
+  const settings = useAtomValue(settingsAtom);
+  const setSettings = useSetAtom(settingsAtom);
+
+  const applyPreset = (patch: Partial<Settings>) => {
+    setSettings({ ...settings, ...patch });
+  };
+
+  return (
+    <Box direction="Column" gap="100">
+      <Text size="L400">Quick Presets</Text>
+      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column">
+        <Box gap="300" style={{ padding: config.space.S300, flexWrap: 'wrap' }}>
+          {PRESETS.map((preset) => (
+            <button
+              key={preset.label}
+              type="button"
+              onClick={() => applyPreset(preset.patch)}
+              title={preset.description}
+              style={{
+                display: 'flex',
+                flexDirection: 'column',
+                alignItems: 'center',
+                gap: toRem(4),
+                padding: `${toRem(8)} ${toRem(16)}`,
+                borderRadius: config.radii.R300,
+                border: '1px solid var(--border-interactive-normal)',
+                background: 'var(--bg-surface-low)',
+                color: 'inherit',
+                cursor: 'pointer',
+                minWidth: toRem(80),
+              }}
+            >
+              <span style={{ fontSize: toRem(24) }}>{preset.emoji}</span>
+              <Text size="T300" style={{ fontWeight: 600 }}>{preset.label}</Text>
+              <Text size="T200" priority="300" style={{ textAlign: 'center', maxWidth: toRem(120) }}>
+                {preset.description}
+              </Text>
+            </button>
+          ))}
+        </Box>
+      </SequenceCard>
+    </Box>
+  );
+}
 
 type NotificationsProps = {
   requestClose: () => void;
@@ -34,6 +124,7 @@ export function Notifications({ requestClose }: NotificationsProps) {
         <Scroll hideTrack visibility="Hover">
           <PageContent>
             <Box direction="Column" gap="700">
+              <NotificationPresets />
               <SystemNotification />
               <AllMessagesNotifications />
               <SpecialMessagesNotifications />

src/app/pages/App.tsx

@@ -1,4 +1,4 @@
-import React from 'react';
+import React, { useEffect } from 'react';
 import * as Sentry from '@sentry/react';
 import { Provider as JotaiProvider, useAtomValue } from 'jotai';
 import { OverlayContainerProvider, PopOutContainerProvider, TooltipContainerProvider } from 'folds';
@@ -16,6 +16,42 @@ import { useCompositionEndTracking } from '../hooks/useComposingCheck';
 import { settingsAtom } from '../state/settings';
 import { LotusToastContainer } from '../features/toast/LotusToastContainer';
 
+const FONT_MAP: Record<string, string> = {
+  system: "system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif",
+  inter: "'InterVariable', sans-serif",
+  'jetbrains-mono': "'JetBrains Mono', monospace",
+  'fira-code': "'Fira Code', monospace",
+};
+
+function AppearanceEffects() {
+  const settings = useAtomValue(settingsAtom);
+
+  useEffect(() => {
+    const color = settings.mentionHighlightColor;
+    if (color) {
+      document.body.style.setProperty('--mention-highlight-bg', color);
+      // compute black or white text based on hex luminance
+      const r = parseInt(color.slice(1, 3), 16);
+      const g = parseInt(color.slice(3, 5), 16);
+      const b = parseInt(color.slice(5, 7), 16);
+      const lum = (0.299 * r + 0.587 * g + 0.114 * b) / 255;
+      document.body.style.setProperty('--mention-highlight-text', lum > 0.5 ? '#000' : '#fff');
+      document.body.style.setProperty('--mention-highlight-border', color);
+    } else {
+      document.body.style.removeProperty('--mention-highlight-bg');
+      document.body.style.removeProperty('--mention-highlight-text');
+      document.body.style.removeProperty('--mention-highlight-border');
+    }
+  }, [settings.mentionHighlightColor]);
+
+  useEffect(() => {
+    const font = FONT_MAP[settings.fontFamily ?? 'inter'] ?? FONT_MAP.inter;
+    document.body.style.setProperty('--font-secondary', font);
+  }, [settings.fontFamily]);
+
+  return null;
+}
+
 function NightLightOverlay() {
   const settings = useAtomValue(settingsAtom);
   if (!settings.nightLightEnabled) return null;
@@ -94,6 +130,7 @@ function App() {
                     <ClientConfigProvider value={clientConfig}>
                       <QueryClientProvider client={queryClient}>
                         <JotaiProvider>
+                          <AppearanceEffects />
                           <RouterProvider router={createRouter(clientConfig, screenSize)} />
                           <NightLightOverlay />
                           <LotusToastContainer />

src/app/state/settings.ts

@@ -125,6 +125,9 @@ export interface Settings {
   pauseAnimations: boolean;
 
   composerToolbarButtons: ComposerToolbarSettings;
+
+  mentionHighlightColor: string;
+  fontFamily: 'system' | 'inter' | 'jetbrains-mono' | 'fira-code';
 }
 
 const defaultSettings: Settings = {
@@ -192,6 +195,9 @@ const defaultSettings: Settings = {
   pauseAnimations: false,
 
   composerToolbarButtons: DEFAULT_COMPOSER_TOOLBAR,
+
+  mentionHighlightColor: '',
+  fontFamily: 'inter',
 };
 
 export const getSettings = (): Settings => {

src/app/styles/CustomHtml.css.ts

@@ -169,9 +169,9 @@ export const Mention = recipe({
   variants: {
     highlight: {
       true: {
-        backgroundColor: color.Success.Container,
-        color: color.Success.OnContainer,
-        boxShadow: `0 0 0 ${config.borderWidth.B300} ${color.Success.ContainerLine}`,
+        backgroundColor: `var(--mention-highlight-bg, ${color.Success.Container as string})`,
+        color: `var(--mention-highlight-text, ${color.Success.OnContainer as string})`,
+        boxShadow: `0 0 0 ${config.borderWidth.B300} var(--mention-highlight-border, ${color.Success.ContainerLine as string})`,
       },
     },
     focus: {