feat: add global font settings with per-project override

- Add fontFamilySans and fontFamilyMono to GlobalSettings type
- Add global font state and actions to app store
- Update getEffectiveFontSans/Mono to fall back to global settings
- Add font selectors to global Settings → Appearance
- Add "Use Global Font" checkboxes in Project Settings → Theme
- Add fonts to settings sync and migration
- Include fonts in import/export JSON

apps/ui/src/components/views/project-settings-view/project-theme-section.tsx

@@ -26,15 +26,19 @@ interface ProjectThemeSectionProps {
 export function ProjectThemeSection({ project }: ProjectThemeSectionProps) {
   const {
     theme: globalTheme,
+    fontFamilySans: globalFontSans,
+    fontFamilyMono: globalFontMono,
     setProjectTheme,
     setProjectFontSans,
     setProjectFontMono,
   } = useAppStore();
   const [activeTab, setActiveTab] = useState<'dark' | 'light'>('dark');
-  const [fontSans, setFontSansLocal] = useState<string>(
+
+  // Font local state - tracks what's selected when using custom fonts
+  const [fontSansLocal, setFontSansLocal] = useState<string>(
     project.fontFamilySans || DEFAULT_FONT_VALUE
   );
-  const [fontMono, setFontMonoLocal] = useState<string>(
+  const [fontMonoLocal, setFontMonoLocal] = useState<string>(
     project.fontFamilyMono || DEFAULT_FONT_VALUE
   );
 
@@ -44,38 +48,80 @@ export function ProjectThemeSection({ project }: ProjectThemeSectionProps) {
     setFontMonoLocal(project.fontFamilyMono || DEFAULT_FONT_VALUE);
   }, [project]);
 
+  // Theme state
   const projectTheme = project.theme as Theme | undefined;
   const hasCustomTheme = projectTheme !== undefined;
   const effectiveTheme = projectTheme || globalTheme;
 
+  // Font state - check if project has custom fonts set
+  const hasCustomFontSans = project.fontFamilySans !== undefined;
+  const hasCustomFontMono = project.fontFamilyMono !== undefined;
+
   const themesToShow = activeTab === 'dark' ? darkThemes : lightThemes;
 
+  // Theme handlers
   const handleThemeChange = (theme: Theme) => {
     setProjectTheme(project.id, theme);
   };
 
   const handleUseGlobalTheme = (checked: boolean) => {
     if (checked) {
-      // Clear project theme to use global
       setProjectTheme(project.id, null);
     } else {
-      // Set project theme to current global theme
       setProjectTheme(project.id, globalTheme);
     }
   };
 
+  // Font handlers
+  const handleUseGlobalFontSans = (checked: boolean) => {
+    if (checked) {
+      // Clear project font to use global
+      setProjectFontSans(project.id, null);
+      setFontSansLocal(DEFAULT_FONT_VALUE);
+    } else {
+      // Set to current global font or default
+      const fontToSet = globalFontSans || DEFAULT_FONT_VALUE;
+      setFontSansLocal(fontToSet);
+      setProjectFontSans(project.id, fontToSet === DEFAULT_FONT_VALUE ? null : fontToSet);
+    }
+  };
+
+  const handleUseGlobalFontMono = (checked: boolean) => {
+    if (checked) {
+      // Clear project font to use global
+      setProjectFontMono(project.id, null);
+      setFontMonoLocal(DEFAULT_FONT_VALUE);
+    } else {
+      // Set to current global font or default
+      const fontToSet = globalFontMono || DEFAULT_FONT_VALUE;
+      setFontMonoLocal(fontToSet);
+      setProjectFontMono(project.id, fontToSet === DEFAULT_FONT_VALUE ? null : fontToSet);
+    }
+  };
+
   const handleFontSansChange = (value: string) => {
     setFontSansLocal(value);
-    // 'default' means use theme default, so we pass null to clear the override
     setProjectFontSans(project.id, value === DEFAULT_FONT_VALUE ? null : value);
   };
 
   const handleFontMonoChange = (value: string) => {
     setFontMonoLocal(value);
-    // 'default' means use theme default, so we pass null to clear the override
     setProjectFontMono(project.id, value === DEFAULT_FONT_VALUE ? null : value);
   };
 
+  // Get display label for global font
+  const getGlobalFontSansLabel = () => {
+    if (!globalFontSans) return 'Default (Geist Sans)';
+    const option = UI_SANS_FONT_OPTIONS.find((o) => o.value === globalFontSans);
+    return option?.label || globalFontSans;
+  };
+
+  const getGlobalFontMonoLabel = () => {
+    if (!globalFontMono) return 'Default (Geist Mono)';
+    const option = UI_MONO_FONT_OPTIONS.find((o) => o.value === globalFontMono);
+    return option?.label || globalFontMono;
+  };
+
   return (
     <div
       className={cn(
@@ -90,10 +136,10 @@ export function ProjectThemeSection({ project }: ProjectThemeSectionProps) {
           <div className="w-9 h-9 rounded-xl bg-gradient-to-br from-brand-500/20 to-brand-600/10 flex items-center justify-center border border-brand-500/20">
             <Palette className="w-5 h-5 text-brand-500" />
           </div>
-          <h2 className="text-lg font-semibold text-foreground tracking-tight">Theme</h2>
+          <h2 className="text-lg font-semibold text-foreground tracking-tight">Theme & Fonts</h2>
         </div>
         <p className="text-sm text-muted-foreground/80 ml-12">
-          Customize the theme for this project.
+          Customize the appearance for this project.
         </p>
       </div>
       <div className="p-6 space-y-6">
@@ -206,17 +252,39 @@ export function ProjectThemeSection({ project }: ProjectThemeSectionProps) {
             <Type className="w-4 h-4 text-muted-foreground" />
             <Label className="text-foreground font-medium">Fonts</Label>
           </div>
-          <p className="text-xs text-muted-foreground -mt-2 mb-4">
-            Override the default fonts for this project. Fonts must be installed on your system.
-          </p>
 
-          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
-            {/* UI Font Selector */}
-            <div className="space-y-2">
-              <Label htmlFor="ui-font-select" className="text-sm">
-                UI Font
+          <div className="space-y-4">
+            {/* UI Font */}
+            <div className="space-y-3">
+              <div className="group flex items-start space-x-3 p-3 rounded-xl hover:bg-accent/30 transition-colors duration-200 -mx-3">
+                <Checkbox
+                  id="use-global-font-sans"
+                  checked={!hasCustomFontSans}
+                  onCheckedChange={handleUseGlobalFontSans}
+                  className="mt-1"
+                />
+                <div className="flex-1 space-y-1.5">
+                  <Label
+                    htmlFor="use-global-font-sans"
+                    className="text-foreground cursor-pointer font-medium"
+                  >
+                    Use Global UI Font
                   </Label>
-              <Select value={fontSans} onValueChange={handleFontSansChange}>
+                  {!hasCustomFontSans && (
+                    <p className="text-xs text-muted-foreground">
+                      Currently using:{' '}
+                      <span className="font-medium">{getGlobalFontSansLabel()}</span>
+                    </p>
+                  )}
+                </div>
+              </div>
+
+              {hasCustomFontSans && (
+                <div className="ml-6 space-y-2">
+                  <Label htmlFor="ui-font-select" className="text-sm">
+                    Project UI Font
+                  </Label>
+                  <Select value={fontSansLocal} onValueChange={handleFontSansChange}>
                     <SelectTrigger id="ui-font-select" className="w-full">
                       <SelectValue placeholder="Default (Geist Sans)" />
                     </SelectTrigger>
@@ -235,17 +303,41 @@ export function ProjectThemeSection({ project }: ProjectThemeSectionProps) {
                       ))}
                     </SelectContent>
                   </Select>
-              <p className="text-xs text-muted-foreground">
-                Used for headings, labels, and UI text
-              </p>
+                </div>
+              )}
             </div>
 
-            {/* Code Font Selector */}
-            <div className="space-y-2">
-              <Label htmlFor="code-font-select" className="text-sm">
-                Code Font
+            {/* Code Font */}
+            <div className="space-y-3">
+              <div className="group flex items-start space-x-3 p-3 rounded-xl hover:bg-accent/30 transition-colors duration-200 -mx-3">
+                <Checkbox
+                  id="use-global-font-mono"
+                  checked={!hasCustomFontMono}
+                  onCheckedChange={handleUseGlobalFontMono}
+                  className="mt-1"
+                />
+                <div className="flex-1 space-y-1.5">
+                  <Label
+                    htmlFor="use-global-font-mono"
+                    className="text-foreground cursor-pointer font-medium"
+                  >
+                    Use Global Code Font
                   </Label>
-              <Select value={fontMono} onValueChange={handleFontMonoChange}>
+                  {!hasCustomFontMono && (
+                    <p className="text-xs text-muted-foreground">
+                      Currently using:{' '}
+                      <span className="font-medium">{getGlobalFontMonoLabel()}</span>
+                    </p>
+                  )}
+                </div>
+              </div>
+
+              {hasCustomFontMono && (
+                <div className="ml-6 space-y-2">
+                  <Label htmlFor="code-font-select" className="text-sm">
+                    Project Code Font
+                  </Label>
+                  <Select value={fontMonoLocal} onValueChange={handleFontMonoChange}>
                     <SelectTrigger id="code-font-select" className="w-full">
                       <SelectValue placeholder="Default (Geist Mono)" />
                     </SelectTrigger>
@@ -264,9 +356,8 @@ export function ProjectThemeSection({ project }: ProjectThemeSectionProps) {
                       ))}
                     </SelectContent>
                   </Select>
-              <p className="text-xs text-muted-foreground">
-                Used for code blocks and monospaced text
-              </p>
+                </div>
+              )}
             </div>
           </div>
         </div>

apps/ui/src/components/views/settings-view/appearance/appearance-section.tsx

@@ -1,8 +1,21 @@
 import { useState } from 'react';
 import { Label } from '@/components/ui/label';
-import { Palette, Moon, Sun } from 'lucide-react';
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from '@/components/ui/select';
+import { Palette, Moon, Sun, Type } from 'lucide-react';
 import { darkThemes, lightThemes } from '@/config/theme-options';
+import {
+  UI_SANS_FONT_OPTIONS,
+  UI_MONO_FONT_OPTIONS,
+  DEFAULT_FONT_VALUE,
+} from '@/config/ui-font-options';
 import { cn } from '@/lib/utils';
+import { useAppStore } from '@/store/app-store';
 import type { Theme } from '../shared/types';
 
 interface AppearanceSectionProps {
@@ -12,9 +25,22 @@ interface AppearanceSectionProps {
 
 export function AppearanceSection({ effectiveTheme, onThemeChange }: AppearanceSectionProps) {
   const [activeTab, setActiveTab] = useState<'dark' | 'light'>('dark');
+  const { fontFamilySans, fontFamilyMono, setFontSans, setFontMono } = useAppStore();
 
   const themesToShow = activeTab === 'dark' ? darkThemes : lightThemes;
 
+  // Convert null to 'default' for Select component
+  const fontSansValue = fontFamilySans || DEFAULT_FONT_VALUE;
+  const fontMonoValue = fontFamilyMono || DEFAULT_FONT_VALUE;
+
+  const handleFontSansChange = (value: string) => {
+    setFontSans(value === DEFAULT_FONT_VALUE ? null : value);
+  };
+
+  const handleFontMonoChange = (value: string) => {
+    setFontMono(value === DEFAULT_FONT_VALUE ? null : value);
+  };
+
   return (
     <div
       className={cn(
@@ -102,6 +128,77 @@ export function AppearanceSection({ effectiveTheme, onThemeChange }: AppearanceS
             })}
           </div>
         </div>
+
+        {/* Fonts Section */}
+        <div className="space-y-4 pt-6 border-t border-border/50">
+          <div className="flex items-center gap-2 mb-4">
+            <Type className="w-4 h-4 text-muted-foreground" />
+            <Label className="text-foreground font-medium">Fonts</Label>
+          </div>
+          <p className="text-xs text-muted-foreground -mt-2 mb-4">
+            Set default fonts for all projects. Individual projects can override these settings.
+          </p>
+
+          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
+            {/* UI Font Selector */}
+            <div className="space-y-2">
+              <Label htmlFor="global-ui-font-select" className="text-sm">
+                UI Font
+              </Label>
+              <Select value={fontSansValue} onValueChange={handleFontSansChange}>
+                <SelectTrigger id="global-ui-font-select" className="w-full">
+                  <SelectValue placeholder="Default (Geist Sans)" />
+                </SelectTrigger>
+                <SelectContent>
+                  {UI_SANS_FONT_OPTIONS.map((option) => (
+                    <SelectItem key={option.value} value={option.value}>
+                      <span
+                        style={{
+                          fontFamily:
+                            option.value === DEFAULT_FONT_VALUE ? undefined : option.value,
+                        }}
+                      >
+                        {option.label}
+                      </span>
+                    </SelectItem>
+                  ))}
+                </SelectContent>
+              </Select>
+              <p className="text-xs text-muted-foreground">
+                Used for headings, labels, and UI text
+              </p>
+            </div>
+
+            {/* Code Font Selector */}
+            <div className="space-y-2">
+              <Label htmlFor="global-code-font-select" className="text-sm">
+                Code Font
+              </Label>
+              <Select value={fontMonoValue} onValueChange={handleFontMonoChange}>
+                <SelectTrigger id="global-code-font-select" className="w-full">
+                  <SelectValue placeholder="Default (Geist Mono)" />
+                </SelectTrigger>
+                <SelectContent>
+                  {UI_MONO_FONT_OPTIONS.map((option) => (
+                    <SelectItem key={option.value} value={option.value}>
+                      <span
+                        style={{
+                          fontFamily:
+                            option.value === DEFAULT_FONT_VALUE ? undefined : option.value,
+                        }}
+                      >
+                        {option.label}
+                      </span>
+                    </SelectItem>
+                  ))}
+                </SelectContent>
+              </Select>
+              <p className="text-xs text-muted-foreground">
+                Used for code blocks and monospaced text
+              </p>
+            </div>
+          </div>
+        </div>
       </div>
     </div>
   );

apps/ui/src/hooks/use-settings-migration.ts

@@ -556,6 +556,8 @@ export function hydrateStoreFromSettings(settings: GlobalSettings): void {
 
   useAppStore.setState({
     theme: settings.theme as unknown as import('@/store/app-store').ThemeMode,
+    fontFamilySans: settings.fontFamilySans ?? null,
+    fontFamilyMono: settings.fontFamilyMono ?? null,
     sidebarOpen: settings.sidebarOpen ?? true,
     chatHistoryOpen: settings.chatHistoryOpen ?? false,
     maxConcurrency: settings.maxConcurrency ?? 3,

apps/ui/src/hooks/use-settings-sync.ts

@@ -33,6 +33,8 @@ const SYNC_DEBOUNCE_MS = 1000;
 // Fields to sync to server (subset of AppState that should be persisted)
 const SETTINGS_FIELDS_TO_SYNC = [
   'theme',
+  'fontFamilySans',
+  'fontFamilyMono',
   'sidebarOpen',
   'chatHistoryOpen',
   'maxConcurrency',

apps/ui/src/store/app-store.ts

@@ -510,6 +510,10 @@ export interface AppState {
   // Theme
   theme: ThemeMode;
 
+  // Fonts (global defaults)
+  fontFamilySans: string | null; // null = use default Geist Sans
+  fontFamilyMono: string | null; // null = use default Geist Mono
+
   // Features/Kanban
   features: Feature[];
 
@@ -920,11 +924,13 @@ export interface AppActions {
   getEffectiveTheme: () => ThemeMode; // Get the effective theme (project, global, or preview if set)
   setPreviewTheme: (theme: ThemeMode | null) => void; // Set preview theme for hover preview (null to clear)
 
-  // Font actions (per-project)
-  setProjectFontSans: (projectId: string, fontFamily: string | null) => void; // Set per-project UI/sans font (null to clear)
-  setProjectFontMono: (projectId: string, fontFamily: string | null) => void; // Set per-project code/mono font (null to clear)
-  getEffectiveFontSans: () => string | null; // Get effective UI font (project override or null for default)
-  getEffectiveFontMono: () => string | null; // Get effective code font (project override or null for default)
+  // Font actions (global + per-project override)
+  setFontSans: (fontFamily: string | null) => void; // Set global UI/sans font (null to clear)
+  setFontMono: (fontFamily: string | null) => void; // Set global code/mono font (null to clear)
+  setProjectFontSans: (projectId: string, fontFamily: string | null) => void; // Set per-project UI/sans font override (null = use global)
+  setProjectFontMono: (projectId: string, fontFamily: string | null) => void; // Set per-project code/mono font override (null = use global)
+  getEffectiveFontSans: () => string | null; // Get effective UI font (project override -> global -> null for default)
+  getEffectiveFontMono: () => string | null; // Get effective code font (project override -> global -> null for default)
 
   // Feature actions
   setFeatures: (features: Feature[]) => void;
@@ -1264,6 +1270,8 @@ const initialState: AppState = {
   mobileSidebarHidden: false, // Sidebar visible by default on mobile
   lastSelectedSessionByProject: {},
   theme: getStoredTheme() || 'dark', // Use localStorage theme as initial value, fallback to 'dark'
+  fontFamilySans: null, // Global UI font (null = use default Geist Sans)
+  fontFamilyMono: null, // Global code font (null = use default Geist Mono)
   features: [],
   appSpec: '',
   ipcConnected: false,
@@ -1739,7 +1747,11 @@ export const useAppStore = create<AppState & AppActions>()((set, get) => ({
 
   setPreviewTheme: (theme) => set({ previewTheme: theme }),
 
-  // Font actions (per-project)
+  // Font actions (global + per-project override)
+  setFontSans: (fontFamily) => set({ fontFamilySans: fontFamily }),
+
+  setFontMono: (fontFamily) => set({ fontFamilyMono: fontFamily }),
+
   setProjectFontSans: (projectId, fontFamily) => {
     // Update the project's fontFamilySans property
     const projects = get().projects.map((p) =>
@@ -1784,20 +1796,20 @@ export const useAppStore = create<AppState & AppActions>()((set, get) => ({
 
   getEffectiveFontSans: () => {
     const currentProject = get().currentProject;
-    // Return the project's font override, or null for default
+    // Return project override if set, otherwise global, otherwise null for default
     if (currentProject?.fontFamilySans) {
       return currentProject.fontFamilySans;
     }
-    return null;
+    return get().fontFamilySans;
   },
 
   getEffectiveFontMono: () => {
     const currentProject = get().currentProject;
-    // Return the project's font override, or null for default
+    // Return project override if set, otherwise global, otherwise null for default
     if (currentProject?.fontFamilyMono) {
       return currentProject.fontFamilyMono;
     }
-    return null;
+    return get().fontFamilyMono;
   },
 
   // Feature actions

libs/types/src/settings.ts

@@ -463,6 +463,12 @@ export interface GlobalSettings {
   /** Currently selected theme */
   theme: ThemeMode;
 
+  // Font Configuration
+  /** Global UI/Sans font family (undefined = use default Geist Sans) */
+  fontFamilySans?: string;
+  /** Global Code/Mono font family (undefined = use default Geist Mono) */
+  fontFamilyMono?: string;
+
   // UI State Preferences
   /** Whether sidebar is currently open */
   sidebarOpen: boolean;