multiple updates

- colour theme implemented. ThemeService based global switching for future light detection triggers
- test flipflop service for various fun
- navigator widget class with state switching

README.md

@@ -36,6 +36,17 @@ smart-serow/
 └── LICENSE
 ```
 
+## Theme System
+
+The UI uses JSON-based themes for different navigator models.
+
+- **Theme files**: `extra/themes/{navigator}.json` (e.g., `extra/themes/zumo.json`)
+- **Generation**: `scripts/generate_theme.py` converts JSON → `pi/ui/lib/theme/app_colors.dart`
+- **Auto-generation**: `build.py` runs theme generation before each Flutter build
+- **Fallback chain**: Tries `{navigator}.json` → `default.json` → hardcoded defaults
+
+To add a new theme, create `extra/themes/yourmodel.json` and set `"navigator": "yourmodel"` in `pi/ui/config.json`.
+
 ---
 
 ## Build Environment Setup (WSL2)

extra/themes/default.json

@@ -0,0 +1,14 @@
+{
+  "dark": {
+    "background": "#000000",
+    "foreground": "#FFFFFF",
+    "highlight": "#FF5555",
+    "subdued": "#808080"
+  },
+  "bright": {
+    "background": "#F0F0F0",
+    "foreground": "#1A1A1A",
+    "highlight": "#CC0000",
+    "subdued": "#606060"
+  }
+}

extra/themes/rei.json

@@ -0,0 +1,14 @@
+{
+  "dark": {
+    "background": "#101010",
+    "foreground": "#EAEAEA",
+    "highlight": "#FA1504",
+    "subdued": "#E47841"
+  },
+  "bright": {
+    "background": "#E47841",
+    "foreground": "#202020",
+    "highlight": "#F0F0F0",
+    "subdued": "#BC4600"
+  }
+}

pi/ui/.gitignore

@@ -43,3 +43,6 @@ app.*.map.json
 /android/app/debug
 /android/app/profile
 /android/app/release
+
+# Generated theme
+lib/theme/app_colors.dart

pi/ui/config.json

@@ -1,5 +1,5 @@
 {
-  "assets_path": "/home/pi/smartserow-ui/assets",
+  "assets_path": "/home/mikkeli/smartserow-ui/assets",
   "navigator": "rei",
   "overheat": {
     "threshold_celsius": 75.0,

pi/ui/lib/main.dart

@@ -1,6 +1,8 @@
 import 'package:flutter/material.dart';
 
 import 'app_root.dart';
+import 'theme/app_colors.dart';
+import 'theme/app_theme.dart';
 
 void main() {
   runApp(const SmartSerowApp());
@@ -11,18 +13,20 @@ class SmartSerowApp extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return MaterialApp(
-      title: 'Smart Serow',
-      debugShowCheckedModeBanner: false,
-      theme: ThemeData(
-        colorScheme: ColorScheme.fromSeed(
-          seedColor: Colors.teal,
-          brightness: Brightness.dark,
+    return AppThemeProvider(
+      child: MaterialApp(
+        title: 'Smart Serow',
+        debugShowCheckedModeBanner: false,
+        theme: ThemeData(
+          colorScheme: ColorScheme.fromSeed(
+            seedColor: AppColors.darkSubdued,
+            brightness: Brightness.dark,
+          ),
+          useMaterial3: true,
+          fontFamily: 'DIN1451',
         ),
-        useMaterial3: true,
-        fontFamily: 'DIN1451',
+        home: const AppRoot(),
       ),
-      home: const AppRoot(),
     );
   }
 }

pi/ui/lib/screens/dashboard_screen.dart

@@ -1,12 +1,15 @@
 import 'dart:async';
-import 'dart:io';
 import 'dart:math';
 import 'package:flutter/material.dart';
 
-import '../services/config_service.dart';
 import '../services/pi_io.dart';
+import '../theme/app_theme.dart';
+import '../widgets/navigator_widget.dart';
 import '../widgets/stat_box.dart';
 
+// test service for triggers
+import '../services/test_flipflop_service.dart';
+
 /// Main dashboard - displays Pi vitals and placeholder stats
 class DashboardScreen extends StatefulWidget {
   const DashboardScreen({super.key});
@@ -17,6 +20,7 @@ class DashboardScreen extends StatefulWidget {
 
 class _DashboardScreenState extends State<DashboardScreen> {
   final _random = Random();
+  final _navigatorKey = GlobalKey<NavigatorWidgetState>();
   Timer? _timer;
 
   double? _piTemp;
@@ -40,33 +44,24 @@ class _DashboardScreenState extends State<DashboardScreen> {
         _temp = 20 + _random.nextInt(60);
       });
     });
+
+    // DEBUG: flip-flop theme + navigator every 2s
+    TestFlipFlopService.instance.start(navigatorKey: _navigatorKey);
   }
 
   @override
   void dispose() {
     _timer?.cancel();
+    TestFlipFlopService.instance.stop();
     super.dispose();
   }
 
-  /// Build navigator image from filesystem
-  Widget _buildNavigatorImage() {
-    final config = ConfigService.instance;
-    final imagePath = '${config.assetsPath}/navigator/${config.navigator}/default.png';
-
-    return Image.file(
-      File(imagePath),
-      fit: BoxFit.contain,
-      errorBuilder: (context, error, stackTrace) {
-        // Graceful fallback - empty box if image missing
-        return const SizedBox.shrink();
-      },
-    );
-  }
-
   @override
   Widget build(BuildContext context) {
+    final theme = AppTheme.of(context);
+
     return Scaffold(
-      backgroundColor: Colors.black,
+      backgroundColor: theme.background,
       body: Padding(
         padding: const EdgeInsets.all(32),
         child: Row(
@@ -84,20 +79,20 @@ class _DashboardScreenState extends State<DashboardScreen> {
                       Text(
                         'SMART SEROW',
                         style: Theme.of(context).textTheme.titleMedium?.copyWith(
-                          color: Colors.teal,
+                          color: theme.subdued,
                           letterSpacing: 2,
                         ),
                       ),
                       Text(
                         '${_voltage.toStringAsFixed(1)}V',
                         style: Theme.of(context).textTheme.titleMedium?.copyWith(
-                          color: _voltage < 12.0 ? Colors.red : Colors.green,
+                          color: _voltage < 12.0 ? theme.highlight : theme.foreground,
                         ),
                       ),
                     ],
                   ),
 
-                  const SizedBox(height: 48),
+                  const SizedBox(height: 20),
 
                   // Main Pi temperature display
                   Expanded(
@@ -107,17 +102,17 @@ class _DashboardScreenState extends State<DashboardScreen> {
                         children: [
                           Text(
                             _piTemp != null ? _piTemp!.toStringAsFixed(1) : '—',
-                            style: const TextStyle(
-                              fontSize: 180,
+                            style: TextStyle(
+                              fontSize: 250,
                               fontWeight: FontWeight.w200,
-                              color: Colors.white,
+                              color: theme.foreground,
                               height: 1,
                             ),
                           ),
                           Text(
                             'Pi Temp',
                             style: Theme.of(context).textTheme.headlineSmall?.copyWith(
-                              color: Colors.grey,
+                              color: theme.subdued,
                             ),
                           ),
                         ],
@@ -144,7 +139,7 @@ class _DashboardScreenState extends State<DashboardScreen> {
             Expanded(
               flex: 1,
               child: Center(
-                child: _buildNavigatorImage(),
+                child: NavigatorWidget(key: _navigatorKey),
               ),
             ),
           ],

pi/ui/lib/screens/overheat_screen.dart

@@ -5,6 +5,7 @@ import 'package:flutter/material.dart';
 
 import '../services/config_service.dart';
 import '../services/pi_io.dart';
+import '../theme/app_theme.dart';
 
 /// Overheat warning screen with shutdown countdown
 ///
@@ -81,30 +82,31 @@ class _OverheatScreenState extends State<OverheatScreen> {
 
   @override
   Widget build(BuildContext context) {
+    final theme = AppTheme.of(context);
     final threshold = ConfigService.instance.overheatThreshold;
 
     return Scaffold(
-      backgroundColor: Colors.black,
+      backgroundColor: theme.background,
       body: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
             // Warning icon
-            const Icon(
+            Icon(
               Icons.warning_amber_rounded,
               size: 100,
-              color: Colors.red,
+              color: theme.highlight,
             ),
 
             const SizedBox(height: 16),
 
             // OVERHEATING text
-            const Text(
+            Text(
               'OVERHEATING',
               style: TextStyle(
                 fontSize: 48,
                 fontWeight: FontWeight.bold,
-                color: Colors.red,
+                color: theme.highlight,
                 letterSpacing: 4,
               ),
             ),
@@ -114,10 +116,10 @@ class _OverheatScreenState extends State<OverheatScreen> {
             // Current temperature
             Text(
               _currentTemp != null ? '${_currentTemp!.toStringAsFixed(1)}°C' : '—',
-              style: const TextStyle(
+              style: TextStyle(
                 fontSize: 120,
                 fontWeight: FontWeight.w200,
-                color: Colors.white,
+                color: theme.foreground,
                 height: 1,
               ),
             ),
@@ -127,9 +129,9 @@ class _OverheatScreenState extends State<OverheatScreen> {
             // Threshold info
             Text(
               'Threshold: ${threshold.toStringAsFixed(0)}°C',
-              style: const TextStyle(
+              style: TextStyle(
                 fontSize: 24,
-                color: Colors.grey,
+                color: theme.subdued,
               ),
             ),
 
@@ -138,9 +140,9 @@ class _OverheatScreenState extends State<OverheatScreen> {
             // Countdown
             Text(
               'Shutdown in $_secondsRemaining s',
-              style: const TextStyle(
+              style: TextStyle(
                 fontSize: 32,
-                color: Colors.orange,
+                color: theme.highlight,
                 fontWeight: FontWeight.w500,
               ),
             ),

pi/ui/lib/screens/splash_screen.dart

@@ -1,5 +1,7 @@
 import 'package:flutter/material.dart';
 
+import '../theme/app_theme.dart';
+
 /// Splash screen - shown during initialization
 class SplashScreen extends StatelessWidget {
   final String status;
@@ -8,8 +10,10 @@ class SplashScreen extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final theme = AppTheme.of(context);
+
     return Scaffold(
-      backgroundColor: Colors.black,
+      backgroundColor: theme.background,
       body: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
@@ -17,13 +21,13 @@ class SplashScreen extends StatelessWidget {
             Icon(
               Icons.terrain,
               size: 120,
-              color: Theme.of(context).colorScheme.primary,
+              color: theme.subdued,
             ),
             const SizedBox(height: 24),
             Text(
               'Smart Serow',
               style: Theme.of(context).textTheme.headlineLarge?.copyWith(
-                color: Colors.white,
+                color: theme.foreground,
                 fontWeight: FontWeight.bold,
               ),
             ),
@@ -31,7 +35,7 @@ class SplashScreen extends StatelessWidget {
             Text(
               status,
               style: Theme.of(context).textTheme.bodyLarge?.copyWith(
-                color: Colors.grey,
+                color: theme.subdued,
               ),
             ),
           ],

pi/ui/lib/services/test_flipflop_service.dart

@@ -0,0 +1,50 @@
+import 'dart:async';
+
+import 'package:flutter/widgets.dart';
+
+import '../widgets/navigator_widget.dart';
+import 'theme_service.dart';
+
+/// Debug service that flip-flops theme and navigator emotion every 2 seconds.
+///
+/// Usage:
+/// ```dart
+/// TestFlipFlopService.instance.start(navigatorKey: _navigatorKey);
+/// // Later:
+/// TestFlipFlopService.instance.stop();
+/// ```
+class TestFlipFlopService {
+  TestFlipFlopService._();
+  static final instance = TestFlipFlopService._();
+
+  Timer? _timer;
+  bool _running = false;
+
+  bool get isRunning => _running;
+
+  /// Start the flip-flop cycle.
+  /// Pass the navigator's GlobalKey to trigger emotion changes.
+  void start({required GlobalKey<NavigatorWidgetState> navigatorKey}) {
+    stop();
+    _running = true;
+
+    _timer = Timer.periodic(const Duration(seconds: 2), (_) {
+      // Toggle theme
+      ThemeService.instance.toggle();
+
+      // Surprise the navigator
+      if (navigatorKey.currentState?.emotion == 'surprise') {
+        navigatorKey.currentState?.reset();
+      } else {
+        navigatorKey.currentState?.setEmotion('surprise');
+      }
+    });
+  }
+
+  /// Stop the flip-flop cycle.
+  void stop() {
+    _timer?.cancel();
+    _timer = null;
+    _running = false;
+  }
+}

pi/ui/lib/services/theme_service.dart

@@ -0,0 +1,40 @@
+/// Theme switching service - singleton pattern matching OverheatMonitor
+///
+/// Manages dark/bright mode state and notifies listeners on change.
+/// Default is dark mode. Call setDarkMode() from sensor readings.
+class ThemeService {
+  ThemeService._();
+  static final instance = ThemeService._();
+
+  bool _isDarkMode = true;
+  final List<void Function()> _listeners = [];
+
+  /// Current theme mode
+  bool get isDarkMode => _isDarkMode;
+
+  /// Set theme mode. Notifies listeners if changed.
+  void setDarkMode(bool dark) {
+    if (_isDarkMode == dark) return;
+    _isDarkMode = dark;
+    _notifyListeners();
+  }
+
+  /// Toggle between dark and bright
+  void toggle() => setDarkMode(!_isDarkMode);
+
+  /// Add a listener for theme changes
+  void addListener(void Function() listener) {
+    _listeners.add(listener);
+  }
+
+  /// Remove a listener
+  void removeListener(void Function() listener) {
+    _listeners.remove(listener);
+  }
+
+  void _notifyListeners() {
+    for (final listener in _listeners) {
+      listener();
+    }
+  }
+}

pi/ui/lib/theme/app_theme.dart

@@ -0,0 +1,75 @@
+import 'package:flutter/material.dart';
+
+import '../services/theme_service.dart';
+import 'app_colors.dart';
+
+/// InheritedWidget providing runtime theme colors
+///
+/// Wraps the app and provides semantic color getters that resolve
+/// to dark or bright variants based on ThemeService state.
+///
+/// Usage: AppTheme.of(context).background
+class AppTheme extends InheritedWidget {
+  final bool isDarkMode;
+
+  const AppTheme({
+    super.key,
+    required this.isDarkMode,
+    required super.child,
+  });
+
+  /// Get the nearest AppTheme from context
+  static AppTheme of(BuildContext context) {
+    final theme = context.dependOnInheritedWidgetOfExactType<AppTheme>();
+    assert(theme != null, 'No AppTheme found in context');
+    return theme!;
+  }
+
+  // Semantic color getters - pick dark or bright based on mode
+  Color get background => isDarkMode ? AppColors.darkBackground : AppColors.brightBackground;
+  Color get foreground => isDarkMode ? AppColors.darkForeground : AppColors.brightForeground;
+  Color get highlight => isDarkMode ? AppColors.darkHighlight : AppColors.brightHighlight;
+  Color get subdued => isDarkMode ? AppColors.darkSubdued : AppColors.brightSubdued;
+
+  @override
+  bool updateShouldNotify(AppTheme oldWidget) => isDarkMode != oldWidget.isDarkMode;
+}
+
+/// Wrapper widget that manages AppTheme state
+///
+/// Listens to ThemeService and rebuilds when theme changes.
+/// Place this at the root of your widget tree.
+class AppThemeProvider extends StatefulWidget {
+  final Widget child;
+
+  const AppThemeProvider({super.key, required this.child});
+
+  @override
+  State<AppThemeProvider> createState() => _AppThemeProviderState();
+}
+
+class _AppThemeProviderState extends State<AppThemeProvider> {
+  @override
+  void initState() {
+    super.initState();
+    ThemeService.instance.addListener(_onThemeChanged);
+  }
+
+  @override
+  void dispose() {
+    ThemeService.instance.removeListener(_onThemeChanged);
+    super.dispose();
+  }
+
+  void _onThemeChanged() {
+    setState(() {});
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AppTheme(
+      isDarkMode: ThemeService.instance.isDarkMode,
+      child: widget.child,
+    );
+  }
+}

pi/ui/lib/widgets/navigator_widget.dart

@@ -0,0 +1,59 @@
+import 'dart:io';
+import 'package:flutter/material.dart';
+import '../services/config_service.dart';
+
+/// Displays the navigator character with emotion support.
+///
+/// Use a GlobalKey to control emotions from parent:
+/// ```dart
+/// final _navigatorKey = GlobalKey<NavigatorWidgetState>();
+/// NavigatorWidget(key: _navigatorKey)
+/// // Later:
+/// _navigatorKey.currentState?.setEmotion('happy');
+/// ```
+class NavigatorWidget extends StatefulWidget {
+  const NavigatorWidget({super.key});
+
+  @override
+  State<NavigatorWidget> createState() => NavigatorWidgetState();
+}
+
+class NavigatorWidgetState extends State<NavigatorWidget> {
+  String _emotion = 'default';
+
+  /// Change the displayed emotion.
+  /// Image file must exist at: {assetsPath}/navigator/{navigator}/{emotion}.png
+  void setEmotion(String emotion) {
+    if (emotion != _emotion) {
+      setState(() => _emotion = emotion);
+    }
+  }
+
+  /// Reset to default emotion
+  void reset() => setEmotion('default');
+
+  /// Current emotion
+  String get emotion => _emotion;
+
+  @override
+  Widget build(BuildContext context) {
+    final config = ConfigService.instance;
+    final basePath = '${config.assetsPath}/navigator/${config.navigator}';
+
+    return Image.file(
+      File('$basePath/$_emotion.png'),
+      fit: BoxFit.contain,
+      errorBuilder: (context, error, stackTrace) {
+        // Fallback: try default.png if specific emotion missing
+        if (_emotion != 'default') {
+          return Image.file(
+            File('$basePath/default.png'),
+            fit: BoxFit.contain,
+            errorBuilder: (_, __, ___) => const SizedBox.shrink(),
+          );
+        }
+        return const SizedBox.shrink();
+      },
+    );
+  }
+}

pi/ui/lib/widgets/stat_box.dart

@@ -1,5 +1,7 @@
 import 'package:flutter/material.dart';
 
+import '../theme/app_theme.dart';
+
 /// A labeled stat display box for the dashboard
 class StatBox extends StatelessWidget {
   final String label;
@@ -9,18 +11,22 @@ class StatBox extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final theme = AppTheme.of(context);
+
     return Column(
       children: [
         Text(
           value,
           style: Theme.of(context).textTheme.headlineMedium?.copyWith(
-            color: Colors.white,
+            fontSize: 100,
+            color: theme.foreground,
           ),
         ),
         Text(
           label,
           style: Theme.of(context).textTheme.bodySmall?.copyWith(
-            color: Colors.grey,
+            fontSize: 80,
+            color: theme.subdued,
             letterSpacing: 1,
           ),
         ),

pi/ui/pubspec.lock

@@ -45,10 +45,10 @@ packages:
     dependency: transitive
     description:
       name: fake_async
-      sha256: "5368f224a74523e8d2e7399ea1638b37aecfca824a3cc4dfdf77bf1fa905ac44"
+      sha256: "6a95e56b2449df2273fd8c45a662d6947ce1ebb7aafe80e550a3f68297f3cacc"
       url: "https://pub.dev"
     source: hosted
-    version: "1.3.3"
+    version: "1.3.2"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -71,26 +71,26 @@ packages:
     dependency: transitive
     description:
       name: leak_tracker
-      sha256: "33e2e26bdd85a0112ec15400c8cbffea70d0f9c3407491f672a2fad47915e2de"
+      sha256: c35baad643ba394b40aac41080300150a4f08fd0fd6a10378f8f7c6bc161acec
       url: "https://pub.dev"
     source: hosted
-    version: "11.0.2"
+    version: "10.0.8"
   leak_tracker_flutter_testing:
     dependency: transitive
     description:
       name: leak_tracker_flutter_testing
-      sha256: "1dbc140bb5a23c75ea9c4811222756104fbcd1a27173f0c34ca01e16bea473c1"
+      sha256: f8b613e7e6a13ec79cfdc0e97638fddb3ab848452eff057653abd3edba760573
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.10"
+    version: "3.0.9"
   leak_tracker_testing:
     dependency: transitive
     description:
       name: leak_tracker_testing
-      sha256: "8d5a2d49f4a66b49744b23b018848400d23e54caf9463f4eb20df3eb8acb2eb1"
+      sha256: "6ba465d5d76e67ddf503e1161d1f4a6bc42306f9d66ca1e8f079a47290fb06d3"
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.2"
+    version: "3.0.1"
   lints:
     dependency: transitive
     description:
@@ -180,18 +180,18 @@ packages:
     dependency: transitive
     description:
       name: test_api
-      sha256: "522f00f556e73044315fa4585ec3270f1808a4b186c936e612cab0b565ff1e00"
+      sha256: fb31f383e2ee25fbbfe06b40fe21e1e458d14080e3c67e7ba0acfde4df4e0bbd
       url: "https://pub.dev"
     source: hosted
-    version: "0.7.6"
+    version: "0.7.4"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      sha256: d530bd74fea330e6e364cda7a85019c434070188383e1cd8d9777ee586914c5b
+      sha256: "80b3257d1492ce4d091729e3a67a60407d227c27241d6927be0130c98e741803"
       url: "https://pub.dev"
     source: hosted
-    version: "2.2.0"
+    version: "2.1.4"
   vm_service:
     dependency: transitive
     description:
@@ -201,5 +201,5 @@ packages:
     source: hosted
     version: "14.3.1"
 sdks:
-  dart: ">=3.8.0-0 <4.0.0"
+  dart: ">=3.7.0-0 <4.0.0"
   flutter: ">=3.18.0-18.0.pre.54"

scripts/build.py

@@ -56,11 +56,22 @@ def set_cross_compile_env():
     return env_vars
 
 
+def generate_theme() -> bool:
+    """Generate theme colors before build."""
+    import generate_theme as theme_gen
+    return theme_gen.main()
+
+
 def build(clean: bool = False) -> bool:
     """Run the build process. Returns True on success."""
     print("=== Smart Serow Build ===")
     print(f"Project: {UI_DIR}")
 
+    # Generate theme colors first
+    if not generate_theme():
+        print("ERROR: Theme generation failed")
+        return False
+
     # Check flutter-elinux
     flutter_path = check_flutter_elinux()
     print(f"Using: {flutter_path}")

scripts/generate_theme.py

@@ -0,0 +1,128 @@
+#!/usr/bin/env python3
+"""Theme generator for Smart Serow Flutter UI.
+
+Reads navigator from config, loads corresponding theme JSON,
+and generates app_colors.dart with the colour palette.
+
+Fallback chain: {navigator}.json -> default.json -> hardcoded defaults
+"""
+
+import json
+import sys
+from pathlib import Path
+
+
+SCRIPT_DIR = Path(__file__).parent.resolve()
+PROJECT_ROOT = SCRIPT_DIR.parent
+UI_DIR = PROJECT_ROOT / "pi" / "ui"
+THEMES_DIR = PROJECT_ROOT / "extra" / "themes"
+CONFIG_FILE = UI_DIR / "config.json"
+OUTPUT_FILE = UI_DIR / "lib" / "theme" / "app_colors.dart"
+
+# Hardcoded fallback if no theme files exist at all
+HARDCODED_THEME = {
+    "dark": {
+        "background": "#000000",
+        "foreground": "#FFFFFF",
+        "highlight": "#FF5555",
+        "subdued": "#808080",
+    },
+    "bright": {
+        "background": "#F0F0F0",
+        "foreground": "#1A1A1A",
+        "highlight": "#CC0000",
+        "subdued": "#606060",
+    },
+}
+
+
+def hex_to_flutter(hex_color: str) -> str:
+    """Convert #RRGGBB to 0xFFRRGGBB format."""
+    hex_clean = hex_color.lstrip("#").upper()
+    return f"0xFF{hex_clean}"
+
+
+def load_config() -> dict:
+    """Load UI config, return empty dict if missing."""
+    if CONFIG_FILE.exists():
+        with open(CONFIG_FILE) as f:
+            return json.load(f)
+    return {}
+
+
+def load_theme(navigator: str) -> dict:
+    """Load theme for navigator with fallback chain."""
+    # Try navigator-specific theme
+    nav_theme = THEMES_DIR / f"{navigator}.json"
+    if nav_theme.exists():
+        print(f"  Using theme: {nav_theme.name}")
+        with open(nav_theme) as f:
+            return json.load(f)
+
+    # Try default theme
+    default_theme = THEMES_DIR / "default.json"
+    if default_theme.exists():
+        print(f"  Fallback to: default.json")
+        with open(default_theme) as f:
+            return json.load(f)
+
+    # Last resort: hardcoded
+    print(f"  Using hardcoded defaults")
+    return HARDCODED_THEME
+
+
+def generate_dart(theme: dict) -> str:
+    """Generate Dart source from theme dict."""
+    dark = theme["dark"]
+    bright = theme["bright"]
+
+    return f'''import 'package:flutter/material.dart';
+
+/// Auto-generated from theme config. Do not edit manually.
+/// Run scripts/generate_theme.py to regenerate.
+class AppColors {{
+  AppColors._();
+
+  // Dark theme (low ambient light)
+  static const darkBackground = Color({hex_to_flutter(dark["background"])});
+  static const darkForeground = Color({hex_to_flutter(dark["foreground"])});
+  static const darkHighlight = Color({hex_to_flutter(dark["highlight"])});
+  static const darkSubdued = Color({hex_to_flutter(dark["subdued"])});
+
+  // Bright theme (high ambient light)
+  static const brightBackground = Color({hex_to_flutter(bright["background"])});
+  static const brightForeground = Color({hex_to_flutter(bright["foreground"])});
+  static const brightHighlight = Color({hex_to_flutter(bright["highlight"])});
+  static const brightSubdued = Color({hex_to_flutter(bright["subdued"])});
+}}
+'''
+
+
+def main():
+    print("=== Theme Generation ===")
+
+    # Get navigator from config
+    config = load_config()
+    navigator = config.get("navigator", "default")
+    print(f"  Navigator: {navigator}")
+
+    # Load theme
+    theme = load_theme(navigator)
+
+    # Generate Dart
+    dart_source = generate_dart(theme)
+
+    # Ensure output directory exists
+    OUTPUT_FILE.parent.mkdir(parents=True, exist_ok=True)
+
+    # Write output
+    with open(OUTPUT_FILE, "w") as f:
+        f.write(dart_source)
+
+    print(f"  Generated: {OUTPUT_FILE.relative_to(PROJECT_ROOT)}")
+    return True
+
+
+if __name__ == "__main__":
+    success = main()
+    sys.exit(0 if success else 1)

scripts/pi_setup.sh

@@ -27,6 +27,12 @@ echo "Creating app directory: $APP_DIR"
 sudo mkdir -p "$APP_DIR/bundle"
 sudo chown -R "$PI_USER:$PI_USER" "$APP_DIR"
 
+# Create assets directory in user home (for navigator images, etc.)
+ASSETS_DIR="/home/$PI_USER/smartserow-ui/assets"
+echo "Creating assets directory: $ASSETS_DIR"
+mkdir -p "$ASSETS_DIR/navigator"
+echo "  (deploy.py will sync extra/images here)"
+
 # Install runtime dependencies for flutter-elinux
 echo "Installing runtime dependencies..."
 sudo apt-get update