step

lib/app/router.dart

@@ -12,6 +12,8 @@ import '../shared/models/transaction.dart';
 import '../shared/paywall/paywall_screen.dart';
 import '../shared/services/onboarding_service.dart';
 import '../shared/widgets/pro_screen.dart';
+import '../shared/widgets/backup_screen.dart';
+import '../shared/providers/premium_provider.dart';
 
 final _shellKey = GlobalKey<NavigatorState>();
 
@@ -72,6 +74,15 @@ final appRouter = GoRouter(
       path: '/pro',
       builder: (context, state) => const ProScreen(),
     ),
+    GoRoute(
+      path: '/backup',
+      redirect: (context, state) {
+        final container = ProviderScope.containerOf(context);
+        final isPremium = container.read(isPremiumProvider);
+        return isPremium ? null : '/pro';
+      },
+      builder: (context, state) => const BackupScreen(),
+    ),
   ],
 );
 

lib/core/l10n/app_strings.dart

@@ -332,4 +332,41 @@ class AppStrings {
       _ru ? 'Предыдущие покупки не найдены' : 'No previous purchases found';
   String get proTapToClose =>
       _ru ? 'Нажмите чтобы закрыть' : 'Tap anywhere to close';
+  String get backupTitle => _ru ? 'Резервная копия' : 'Backup';
+  String get backupCreate => _ru ? 'Создать резервную копию' : 'Create Backup';
+  String get backupRestore => _ru ? 'Восстановить из копии' : 'Restore Backup';
+  String get backupCreating => _ru ? 'Создание копии...' : 'Creating backup...';
+  String get backupRestoring => _ru ? 'Восстановление...' : 'Restoring...';
+  String get backupSuccess =>
+      _ru ? 'Резервная копия успешно создана!' : 'Backup created successfully!';
+  String get backupRestoreSuccess =>
+      _ru ? 'Данные успешно восстановлены!' : 'Data restored successfully!';
+  String get backupRestoreFailed =>
+      _ru ? 'Не удалось восстановить данные' : 'Failed to restore data';
+  String get backupNoFileFound =>
+      _ru ? 'Резервная копия не найдена' : 'No backup file found';
+  String get backupTokenMismatch =>
+      _ru
+          ? 'Этот файл резервной копии принадлежит другому покупателю Premium'
+          : 'This backup file belongs to another Premium purchaser';
+  String get backupInvalidFormat =>
+      _ru ? 'Неверный формат файла резервной копии' : 'Invalid backup file format';
+  String get backupNoToken =>
+      _ru
+          ? 'Файл резервной копии не содержит токен покупки'
+          : 'Backup file does not contain a purchase token';
+  String get backupRequiresPremium =>
+      _ru ? 'Резервная копия доступна только для Pro' : 'Backup is a Pro-only feature';
+  String get backupRequiresSignIn =>
+      _ru
+          ? 'Войдите в Google аккаунт для работы с резервными копиями'
+          : 'Sign in to Google to manage backups';
+  String get backupLastBackup => _ru ? 'Последняя копия' : 'Last backup';
+  String get backupNever => _ru ? 'Никогда' : 'Never';
+  String get backupSyncWithDrive =>
+      _ru ? 'Синхронизация с Google Диском' : 'Google Drive Sync';
+  String get backupSyncDesc =>
+      _ru
+          ? 'Резервное копирование данных на ваш Google Диск'
+          : 'Back up your data to your Google Drive';
 }

lib/data/repositories/account_repository.dart

@@ -13,9 +13,9 @@ class FeatureLimitException implements Exception {
 
 class AccountRepository {
   final AppDatabase _db;
-  final FeatureFlags _featureFlags;
+  final FeatureFlags Function() _getFeatureFlags;
 
-  AccountRepository(this._db, this._featureFlags);
+  AccountRepository(this._db, this._getFeatureFlags);
 
   Stream<List<model.Account>> watchAll() {
     return (_db.select(_db.accounts)
@@ -167,8 +167,9 @@ class AccountRepository {
   Future<int> add(model.Account account) async {
     final existing = await getAll();
     final nonMainCount = existing.where((a) => !a.isMain).length;
-    if (nonMainCount >= _featureFlags.maxAccounts) {
-      throw FeatureLimitException('Account limit reached (${_featureFlags.maxAccounts})');
+    final flags = _getFeatureFlags();
+    if (flags.maxAccounts != -1 && nonMainCount >= flags.maxAccounts) {
+      throw FeatureLimitException('Account limit reached (${flags.maxAccounts})');
     }
     return await _db.into(_db.accounts).insert(
       AccountsCompanion.insert(

lib/features/dashboard/provider.dart

@@ -28,8 +28,7 @@ final transactionRepositoryProvider = Provider<TransactionRepository>((ref) {
 
 final accountRepositoryProvider = Provider<AccountRepository>((ref) {
   final db = ref.watch(appDatabaseProvider);
-  final flags = ref.watch(featureFlagsProvider);
-  return AccountRepository(db, flags);
+  return AccountRepository(db, () => ref.read(featureFlagsProvider));
 });
 
 final storageServiceProvider = Provider<StorageService>((ref) {

lib/features/onboarding/screen.dart

@@ -4,6 +4,7 @@ import 'package:go_router/go_router.dart';
 import '../../core/l10n/locale_provider.dart';
 import '../../core/services/haptic_service.dart';
 import 'provider.dart';
+import 'widgets/fade_slide_in.dart';
 import 'widgets/onboarding_page.dart';
 import 'widgets/onboarding_page_indicator.dart';
 
@@ -29,7 +30,7 @@ class _OnboardingScreenState extends ConsumerState<OnboardingScreen> {
     if (page == 4) {
       HapticService.medium();
       ref.read(onboardingProvider.notifier).complete();
-      Future.delayed(const Duration(milliseconds: 400), () {
+      Future.delayed(const Duration(milliseconds: 150), () {
         if (mounted) context.go('/dashboard');
       });
     }
@@ -49,67 +50,23 @@ class _OnboardingScreenState extends ConsumerState<OnboardingScreen> {
                 controller: _controller,
                 onPageChanged: _onPageChanged,
                 children: [
-                  OnboardingPage.welcome(welcomeText: s.onboardingWelcome),
+                  OnboardingPage.welcome(
+                    welcomeText: s.onboardingWelcome,
+                    isActive: currentPage == 0,
+                  ),
                   OnboardingPage.content(
                     icon: Icons.currency_exchange_rounded,
                     headline: s.onboardingMultiCurrencyTitle,
                     description: s.onboardingMultiCurrencyBody,
+                    isActive: currentPage == 1,
                   ),
                   OnboardingPage.content(
                     icon: Icons.credit_card_rounded,
                     headline: s.onboardingCardsTitle,
                     description: s.onboardingCardsBody,
+                    isActive: currentPage == 2,
                   ),
-                  Center(
-                    child: Padding(
-                      padding: const EdgeInsets.symmetric(horizontal: 32),
-                      child: Column(
-                        mainAxisSize: MainAxisSize.min,
-                        children: [
-                          Icon(
-                            Icons.waving_hand_rounded,
-                            size: 72,
-                            color: Theme.of(context).colorScheme.primary,
-                          ),
-                          const SizedBox(height: 28),
-                          Text(
-                            s.onboardingReadyTitle,
-                            textAlign: TextAlign.center,
-                            style: Theme.of(context).textTheme.headlineMedium?.copyWith(
-                                  fontWeight: FontWeight.bold,
-                                  color: Theme.of(context).colorScheme.onSurface,
-                                ),
-                          ),
-                          const SizedBox(height: 12),
-                          Text(
-                            s.onboardingReadyBody,
-                            textAlign: TextAlign.center,
-                            style: Theme.of(context).textTheme.bodyLarge?.copyWith(
-                                  color: Theme.of(context).colorScheme.onSurface.withOpacity(0.5),
-                                ),
-                          ),
-                          const SizedBox(height: 24),
-                          Row(
-                            mainAxisAlignment: MainAxisAlignment.center,
-                            children: [
-                              Text(
-                                s.onboardingSwipeRight,
-                                style: Theme.of(context).textTheme.titleMedium?.copyWith(
-                                      color: Theme.of(context).colorScheme.primary,
-                                      fontWeight: FontWeight.w600,
-                                    ),
-                              ),
-                              const SizedBox(width: 8),
-                              Icon(
-                                Icons.arrow_forward_rounded,
-                                color: Theme.of(context).colorScheme.primary,
-                              ),
-                            ],
-                          ),
-                        ],
-                      ),
-                    ),
-                  ),
+                  _ReadyPage(isActive: currentPage == 3),
                   const SizedBox.shrink(),
                 ],
               ),
@@ -127,3 +84,81 @@ class _OnboardingScreenState extends ConsumerState<OnboardingScreen> {
     );
   }
 }
+
+class _ReadyPage extends ConsumerWidget {
+  final bool isActive;
+
+  const _ReadyPage({required this.isActive});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final s = ref.watch(stringsProvider);
+    final colorScheme = Theme.of(context).colorScheme;
+
+    return Center(
+      child: Padding(
+        padding: const EdgeInsets.symmetric(horizontal: 32),
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            FadeSlideIn(
+              active: isActive,
+              child: Icon(
+                Icons.waving_hand_rounded,
+                size: 72,
+                color: colorScheme.primary,
+              ),
+            ),
+            const SizedBox(height: 28),
+            FadeSlideIn(
+              active: isActive,
+              delay: const Duration(milliseconds: 150),
+              child: Text(
+                s.onboardingReadyTitle,
+                textAlign: TextAlign.center,
+                style: Theme.of(context).textTheme.headlineMedium?.copyWith(
+                      fontWeight: FontWeight.bold,
+                      color: colorScheme.onSurface,
+                    ),
+              ),
+            ),
+            const SizedBox(height: 12),
+            FadeSlideIn(
+              active: isActive,
+              delay: const Duration(milliseconds: 300),
+              child: Text(
+                s.onboardingReadyBody,
+                textAlign: TextAlign.center,
+                style: Theme.of(context).textTheme.bodyLarge?.copyWith(
+                      color: colorScheme.onSurface.withOpacity(0.5),
+                    ),
+              ),
+            ),
+            const SizedBox(height: 24),
+            FadeSlideIn(
+              active: isActive,
+              delay: const Duration(milliseconds: 450),
+              child: Row(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: [
+                  Text(
+                    s.onboardingSwipeRight,
+                    style: Theme.of(context).textTheme.titleMedium?.copyWith(
+                          color: colorScheme.primary,
+                          fontWeight: FontWeight.w600,
+                        ),
+                  ),
+                  const SizedBox(width: 8),
+                  Icon(
+                    Icons.arrow_forward_rounded,
+                    color: colorScheme.primary,
+                  ),
+                ],
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}

lib/features/onboarding/widgets/casha_shimmer_text.dart

@@ -62,7 +62,7 @@ class _CashaShimmerTextState extends State<CashaShimmerText>
         final shimmer = sin(t * 2 * pi) * 0.08;
 
         final gx = (_tiltY + shimmer).clamp(-1.0, 1.0);
-        final gy = (_tiltX + shimmer * 0.5).clamp(-1.0, 1.0);
+        final gy = (_tiltX + shimmer * 0.3).clamp(-1.0, 1.0);
 
         return Transform(
           alignment: Alignment.center,

lib/features/onboarding/widgets/fade_slide_in.dart

@@ -0,0 +1,78 @@
+import 'package:flutter/material.dart';
+
+class FadeSlideIn extends StatefulWidget {
+  final bool active;
+  final Duration delay;
+  final Duration duration;
+  final Widget child;
+
+  const FadeSlideIn({
+    required this.active,
+    required this.child,
+    this.delay = Duration.zero,
+    this.duration = const Duration(milliseconds: 500),
+    super.key,
+  });
+
+  @override
+  State<FadeSlideIn> createState() => _FadeSlideInState();
+}
+
+class _FadeSlideInState extends State<FadeSlideIn>
+    with SingleTickerProviderStateMixin {
+  late final AnimationController _controller;
+  late final Animation<double> _opacity;
+  late final Animation<Offset> _offset;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = AnimationController(
+      vsync: this,
+      duration: widget.duration,
+    );
+    _opacity = Tween<double>(begin: 0.0, end: 1.0).animate(
+      CurvedAnimation(parent: _controller, curve: Curves.easeOut),
+    );
+    _offset = Tween<Offset>(
+      begin: const Offset(0, 0.15),
+      end: Offset.zero,
+    ).animate(CurvedAnimation(parent: _controller, curve: Curves.easeOut));
+  }
+
+  @override
+  void didUpdateWidget(covariant FadeSlideIn oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.active && !oldWidget.active) {
+      _controller.reset();
+      Future.delayed(widget.delay, () {
+        if (mounted) _controller.forward();
+      });
+    } else if (!widget.active && oldWidget.active) {
+      _controller.reset();
+    }
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedBuilder(
+      animation: _controller,
+      builder: (context, child) {
+        return Opacity(
+          opacity: _opacity.value,
+          child: FractionalTranslation(
+            translation: _offset.value,
+            child: child,
+          ),
+        );
+      },
+      child: widget.child,
+    );
+  }
+}

lib/features/onboarding/widgets/onboarding_page.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'casha_shimmer_text.dart';
+import 'fade_slide_in.dart';
 
 class OnboardingPage extends StatelessWidget {
   final IconData? icon;
@@ -7,9 +8,13 @@ class OnboardingPage extends StatelessWidget {
   final String? description;
   final String? welcomeText;
   final bool isWelcomePage;
+  final bool isActive;
 
-  const OnboardingPage.welcome({required this.welcomeText, super.key})
-      : icon = null,
+  const OnboardingPage.welcome({
+    required this.welcomeText,
+    this.isActive = false,
+    super.key,
+  })  : icon = null,
         headline = null,
         description = null,
         isWelcomePage = true;
@@ -18,6 +23,7 @@ class OnboardingPage extends StatelessWidget {
     required this.icon,
     required this.headline,
     required this.description,
+    this.isActive = false,
     super.key,
   })  : welcomeText = null,
         isWelcomePage = false;
@@ -59,34 +65,45 @@ class OnboardingPage extends StatelessWidget {
         child: Column(
           mainAxisSize: MainAxisSize.min,
           children: [
-            Container(
-              padding: const EdgeInsets.all(24),
-              decoration: BoxDecoration(
-                color: colorScheme.primary.withOpacity(0.12),
-                shape: BoxShape.circle,
-              ),
-              child: Icon(
-                icon,
-                size: 64,
-                color: colorScheme.primary,
+            FadeSlideIn(
+              active: isActive,
+              child: Container(
+                padding: const EdgeInsets.all(24),
+                decoration: BoxDecoration(
+                  color: colorScheme.primary.withOpacity(0.12),
+                  shape: BoxShape.circle,
+                ),
+                child: Icon(
+                  icon,
+                  size: 64,
+                  color: colorScheme.primary,
+                ),
               ),
             ),
             const SizedBox(height: 32),
-            Text(
-              headline!,
-              textAlign: TextAlign.center,
-              style: Theme.of(context).textTheme.headlineSmall?.copyWith(
-                    fontWeight: FontWeight.bold,
-                    color: colorScheme.onSurface,
-                  ),
+            FadeSlideIn(
+              active: isActive,
+              delay: const Duration(milliseconds: 150),
+              child: Text(
+                headline!,
+                textAlign: TextAlign.center,
+                style: Theme.of(context).textTheme.headlineSmall?.copyWith(
+                      fontWeight: FontWeight.bold,
+                      color: colorScheme.onSurface,
+                    ),
+              ),
             ),
             const SizedBox(height: 12),
-            Text(
-              description!,
-              textAlign: TextAlign.center,
-              style: Theme.of(context).textTheme.bodyMedium?.copyWith(
-                    color: colorScheme.onSurface.withOpacity(0.6),
-                  ),
+            FadeSlideIn(
+              active: isActive,
+              delay: const Duration(milliseconds: 300),
+              child: Text(
+                description!,
+                textAlign: TextAlign.center,
+                style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                      color: colorScheme.onSurface.withOpacity(0.6),
+                    ),
+              ),
             ),
           ],
         ),

lib/features/settings/screen.dart

@@ -117,22 +117,23 @@ class SettingsScreen extends ConsumerWidget {
           padding: const EdgeInsets.fromLTRB(20, 16, 20, 40),
           children: [
             const ProSubscriptionCard(),
-            const SizedBox(height: 16),
-            const ThemeSection(),
-            const SizedBox(height: 16),
-            const CardTextColorSection(),
-            const SizedBox(height: 16),
-            const HapticSection(),
-            const SizedBox(height: 16),
-            const CurrencyConversionsSection(),
-            const SizedBox(height: 16),
-            const _BiometricSection(),
-            const LanguageSection(),
-            const SizedBox(height: 16),
+            const SizedBox(height: 12),
             const CurrencySection(),
-            const SizedBox(height: 16),
+            const SizedBox(height: 12),
+            const ThemeSection(),
+            const SizedBox(height: 12),
+            const LanguageSection(),
+            const SizedBox(height: 12),
+            const _BiometricSection(),
+            const SizedBox(height: 12),
+            const CardTextColorSection(),
+            const SizedBox(height: 12),
+            const HapticSection(),
+            const SizedBox(height: 12),
             const AmountFormatSection(),
-            const SizedBox(height: 16),
+            const SizedBox(height: 12),
+            const CurrencyConversionsSection(),
+            const SizedBox(height: 12),
             const CategoriesSection(),
             const SizedBox(height: 24),
             Text(

lib/features/settings/widgets/card_text_color_section.dart

@@ -14,7 +14,7 @@ class CardTextColorSection extends ConsumerWidget {
     final isDark = Theme.of(context).brightness == Brightness.dark;
 
     return Container(
-      padding: const EdgeInsets.all(20),
+      padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 14),
       decoration: BoxDecoration(
         color: Theme.of(context).colorScheme.surface,
         borderRadius: BorderRadius.circular(16),
@@ -49,7 +49,7 @@ class CardTextColorSection extends ConsumerWidget {
               ),
             ],
           ),
-          const SizedBox(height: 16),
+          const SizedBox(height: 12),
           Row(
             children: [
               Expanded(
@@ -113,7 +113,7 @@ class _CardTextColorOption extends StatelessWidget {
       onTap: onTap,
       child: AnimatedContainer(
         duration: const Duration(milliseconds: 200),
-        padding: const EdgeInsets.symmetric(vertical: 12),
+        padding: const EdgeInsets.symmetric(vertical: 10),
         decoration: BoxDecoration(
           color: isSelected
               ? AppColors.accent.withOpacity(0.15)

lib/features/settings/widgets/currency_section.dart

@@ -15,7 +15,7 @@ class CurrencySection extends ConsumerWidget {
     final isDark = Theme.of(context).brightness == Brightness.dark;
 
     return Container(
-      padding: const EdgeInsets.all(20),
+      padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 14),
       decoration: BoxDecoration(
         color: Theme.of(context).colorScheme.surface,
         borderRadius: BorderRadius.circular(16),
@@ -52,7 +52,7 @@ class CurrencySection extends ConsumerWidget {
               ),
             ],
           ),
-          const SizedBox(height: 16),
+          const SizedBox(height: 12),
           Row(
             children: ['USD', 'EUR', 'BYN', 'RUB'].map((code) {
               final info = currencyMap[code]!;
@@ -65,7 +65,7 @@ class CurrencySection extends ConsumerWidget {
                       ref.read(currencyProvider.notifier).setCurrency(code);
                     },
                     child: Container(
-                      padding: const EdgeInsets.symmetric(vertical: 12),
+                      padding: const EdgeInsets.symmetric(vertical: 10),
                       decoration: BoxDecoration(
                         color: isSelected
                             ? AppColors.accent.withOpacity(0.2)
@@ -83,12 +83,18 @@ class CurrencySection extends ConsumerWidget {
                       child: Column(
                         children: [
                           code == 'BYN'
-                              ? BynSign(
-                                  fontSize: 28,
-                                  color: isSelected
-                                      ? AppColors.accent
-                                      : Theme.of(context).colorScheme.onSurface
-                                            .withOpacity(0.6),
+                              ? SizedBox(
+                                  height: 28,
+                                  child: Align(
+                                    alignment: Alignment.center,
+                                    child: BynSign(
+                                      fontSize: 24,
+                                      color: isSelected
+                                          ? AppColors.accent
+                                          : Theme.of(context).colorScheme.onSurface
+                                                .withOpacity(0.6),
+                                    ),
+                                  ),
                                 )
                               : Text(
                                   info.symbol,

lib/features/settings/widgets/theme_section.dart

@@ -14,7 +14,7 @@ class ThemeSection extends ConsumerWidget {
     final isDark = Theme.of(context).brightness == Brightness.dark;
 
     return Container(
-      padding: const EdgeInsets.all(20),
+      padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 14),
       decoration: BoxDecoration(
         color: Theme.of(context).colorScheme.surface,
         borderRadius: BorderRadius.circular(16),
@@ -51,7 +51,7 @@ class ThemeSection extends ConsumerWidget {
               ),
             ],
           ),
-          const SizedBox(height: 16),
+          const SizedBox(height: 12),
           Row(
             children: [
               Expanded(
@@ -109,7 +109,7 @@ class _ThemeOption extends StatelessWidget {
       onTap: onTap,
       child: AnimatedContainer(
         duration: const Duration(milliseconds: 200),
-        padding: const EdgeInsets.symmetric(vertical: 12),
+        padding: const EdgeInsets.symmetric(vertical: 10),
         decoration: BoxDecoration(
           color: isSelected
               ? AppColors.accent.withOpacity(0.15)

lib/main.dart

@@ -7,6 +7,9 @@ import 'core/services/haptic_service.dart';
 import 'data/database/app_database.dart';
 import 'features/dashboard/provider.dart';
 import 'shared/services/onboarding_service.dart';
+import 'shared/services/billing_service.dart';
+import 'shared/services/premium_manager.dart';
+import 'shared/providers/billing_provider.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
@@ -22,11 +25,16 @@ void main() async {
 
   final database = AppDatabase();
 
+  final billing = PlayBillingService();
+  final premiumManager = PremiumManager(prefs, billing);
+  await premiumManager.autoRestore();
+
   runApp(
     ProviderScope(
       overrides: [
         sharedPreferencesProvider.overrideWithValue(prefs),
         appDatabaseProvider.overrideWithValue(database),
+        billingServiceProvider.overrideWithValue(billing),
       ],
       child: const App(),
     ),

lib/shared/providers/backup_provider.dart

@@ -0,0 +1,8 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import '../services/backup_service.dart';
+import 'premium_provider.dart';
+
+final backupServiceProvider = Provider<BackupService>((ref) {
+  final token = ref.watch(purchaseTokenProvider) ?? '';
+  return BackupService(token);
+});

lib/shared/providers/billing_provider.dart

@@ -1,8 +1,6 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
-import '../../features/dashboard/provider.dart';
 import '../services/billing_service.dart';
 
 final billingServiceProvider = Provider<BillingService>((ref) {
-  final prefs = ref.watch(sharedPreferencesProvider);
-  return MockBillingService(prefs);
+  return PlayBillingService();
 });

lib/shared/providers/current_user_provider.dart

@@ -1,29 +1,27 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import '../../features/dashboard/provider.dart';
 import '../models/user_model.dart';
+import '../services/premium_manager.dart';
+import 'billing_provider.dart';
 
 class CurrentUserNotifier extends Notifier<UserModel> {
-  static const _key = 'user_plan';
-
   @override
   UserModel build() {
     final prefs = ref.watch(sharedPreferencesProvider);
-    final planName = prefs.getString(_key);
-    final plan = UserPlan.values.firstWhere(
-      (e) => e.name == planName,
-      orElse: () => UserPlan.free,
-    );
-    return UserModel(plan: plan);
+    final billing = ref.watch(billingServiceProvider);
+    final manager = PremiumManager(prefs, billing);
+    return UserModel(plan: manager.currentPlan);
   }
 
   Future<void> setPlan(UserPlan plan) async {
-    final prefs = ref.read(sharedPreferencesProvider);
     state = UserModel(plan: plan);
-    await prefs.setString(_key, plan.name);
   }
 
-  Future<void> toggleVip() async {
-    await setPlan(state.isVip ? UserPlan.free : UserPlan.vip);
+  Future<void> refreshFromPremium() async {
+    final prefs = ref.read(sharedPreferencesProvider);
+    final billing = ref.read(billingServiceProvider);
+    final manager = PremiumManager(prefs, billing);
+    state = UserModel(plan: manager.currentPlan);
   }
 }
 

lib/shared/providers/google_drive_provider.dart

@@ -0,0 +1,18 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:google_sign_in/google_sign_in.dart';
+import '../services/google_drive_service.dart';
+
+final googleDriveServiceProvider = Provider<GoogleDriveService>((ref) {
+  final signIn = GoogleSignIn(
+    scopes: [
+      'email',
+      'https://www.googleapis.com/auth/drive.appdata',
+    ],
+  );
+  return GoogleDriveService(signIn);
+});
+
+final googleDriveUserProvider = StreamProvider<GoogleSignInAccount?>((ref) {
+  final service = ref.watch(googleDriveServiceProvider);
+  return service.onUserChanged;
+});

lib/shared/providers/premium_provider.dart

@@ -0,0 +1,20 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import '../../features/dashboard/provider.dart';
+import '../services/premium_manager.dart';
+import 'billing_provider.dart';
+
+final premiumManagerProvider = Provider<PremiumManager>((ref) {
+  final prefs = ref.watch(sharedPreferencesProvider);
+  final billing = ref.watch(billingServiceProvider);
+  return PremiumManager(prefs, billing);
+});
+
+final isPremiumProvider = Provider<bool>((ref) {
+  final manager = ref.watch(premiumManagerProvider);
+  return manager.isPremium;
+});
+
+final purchaseTokenProvider = Provider<String?>((ref) {
+  final manager = ref.watch(premiumManagerProvider);
+  return manager.purchaseToken;
+});

lib/shared/services/backup_service.dart

@@ -0,0 +1,72 @@
+import 'dart:convert';
+import 'dart:typed_data';
+
+class BackupData {
+  final String ownerPurchaseToken;
+  final DateTime createdAt;
+  final Map<String, dynamic> payload;
+
+  const BackupData({
+    required this.ownerPurchaseToken,
+    required this.createdAt,
+    required this.payload,
+  });
+
+  Map<String, dynamic> toJson() => {
+        'owner_purchase_token': ownerPurchaseToken,
+        'created_at': createdAt.toIso8601String(),
+        'payload': payload,
+      };
+
+  factory BackupData.fromJson(Map<String, dynamic> json) {
+    return BackupData(
+      ownerPurchaseToken: json['owner_purchase_token'] as String? ?? '',
+      createdAt: DateTime.tryParse(json['created_at'] as String? ?? '') ??
+          DateTime.now(),
+      payload: json['payload'] as Map<String, dynamic>? ?? {},
+    );
+  }
+}
+
+enum BackupVerifyResult { ok, tokenMismatch, noToken, invalidFormat }
+
+class BackupService {
+  String _currentPurchaseToken;
+
+  BackupService(this._currentPurchaseToken);
+
+  void updatePurchaseToken(String token) {
+    _currentPurchaseToken = token;
+  }
+
+  String get currentPurchaseToken => _currentPurchaseToken;
+
+  Uint8List createBackup(Map<String, dynamic> payload) {
+    final data = BackupData(
+      ownerPurchaseToken: _currentPurchaseToken,
+      createdAt: DateTime.now(),
+      payload: payload,
+    );
+    final json = jsonEncode(data.toJson());
+    return Uint8List.fromList(utf8.encode(json));
+  }
+
+  (BackupVerifyResult, BackupData?) verifyAndParse(Uint8List raw) {
+    try {
+      final json = jsonDecode(utf8.decode(raw)) as Map<String, dynamic>;
+      final data = BackupData.fromJson(json);
+
+      if (data.ownerPurchaseToken.isEmpty) {
+        return (BackupVerifyResult.noToken, null);
+      }
+
+      if (data.ownerPurchaseToken != _currentPurchaseToken) {
+        return (BackupVerifyResult.tokenMismatch, null);
+      }
+
+      return (BackupVerifyResult.ok, data);
+    } catch (e) {
+      return (BackupVerifyResult.invalidFormat, null);
+    }
+  }
+}

lib/shared/services/billing_service.dart

@@ -1,34 +1,192 @@
-import 'package:shared_preferences/shared_preferences.dart';
-import '../models/user_model.dart';
+import 'dart:async';
+import 'package:flutter/foundation.dart';
+import 'package:in_app_purchase/in_app_purchase.dart';
+
+class PurchaseResult {
+  final bool success;
+  final String? purchaseToken;
+  final String? error;
+
+  const PurchaseResult({this.success = false, this.purchaseToken, this.error});
+
+  factory PurchaseResult.ok(String token) =>
+      PurchaseResult(success: true, purchaseToken: token);
+
+  factory PurchaseResult.failed([String? error]) =>
+      PurchaseResult(success: false, error: error);
+}
 
 abstract class BillingService {
-  Future<bool> purchasePro();
-  Future<bool> restorePurchases();
-  Future<UserPlan> getCurrentPlan();
+  static const proProductId = 'casha_pro_lifetime';
+
+  Future<PurchaseResult> purchasePro();
+  Future<PurchaseResult> restorePurchases();
+  Future<PurchaseResult> queryPastPurchase();
+  Future<void> completePurchase(String purchaseToken);
+  Stream<List<PurchaseDetails>> get purchaseStream;
+  Future<void> dispose();
 }
 
-class MockBillingService implements BillingService {
-  static const _key = 'user_plan';
-  final SharedPreferences _prefs;
+class PlayBillingService implements BillingService {
+  final InAppPurchase _inAppPurchase = InAppPurchase.instance;
+  late final StreamSubscription<List<PurchaseDetails>> _sub;
+  final _controller = StreamController<List<PurchaseDetails>>.broadcast();
 
-  MockBillingService(this._prefs);
-
-  @override
-  Future<bool> purchasePro() async {
-    await Future.delayed(const Duration(seconds: 1));
-    await _prefs.setString(_key, 'vip');
-    return true;
+  PlayBillingService() {
+    _sub = _inAppPurchase.purchaseStream.listen((purchases) {
+      _controller.add(purchases);
+    });
   }
 
   @override
-  Future<bool> restorePurchases() async {
-    await Future.delayed(const Duration(seconds: 1));
-    return false;
+  Stream<List<PurchaseDetails>> get purchaseStream => _controller.stream;
+
+  @override
+  Future<PurchaseResult> purchasePro() async {
+    final available = await _inAppPurchase.isAvailable();
+    if (!available) {
+      return PurchaseResult.failed('Billing not available');
+    }
+
+    final response = await _inAppPurchase.queryProductDetails(
+      {BillingService.proProductId},
+    );
+    if (response.productDetails.isEmpty) {
+      return PurchaseResult.failed('Product not found');
+    }
+
+    final product = response.productDetails.first;
+    final purchaseParam = PurchaseParam(productDetails: product);
+
+    final started = await _inAppPurchase.buyNonConsumable(
+      purchaseParam: purchaseParam,
+    );
+    if (!started) {
+      return PurchaseResult.failed('Could not start purchase');
+    }
+
+    final completer = Completer<PurchaseResult>();
+    late StreamSubscription sub;
+    sub = purchaseStream.timeout(
+      const Duration(seconds: 60),
+      onTimeout: (sink) {
+        if (!completer.isCompleted) {
+          completer.complete(PurchaseResult.failed('Purchase timed out'));
+        }
+        sub.cancel();
+      },
+    ).listen((purchases) {
+      for (final p in purchases) {
+        if (p.productID == BillingService.proProductId &&
+            p.status == PurchaseStatus.purchased) {
+          if (!completer.isCompleted) {
+            completer.complete(PurchaseResult.ok(p.verificationData.serverVerificationData));
+          }
+          sub.cancel();
+          return;
+        }
+        if (p.status == PurchaseStatus.error) {
+          if (!completer.isCompleted) {
+            completer.complete(PurchaseResult.failed(p.error?.message));
+          }
+          sub.cancel();
+          return;
+        }
+      }
+    });
+
+    return completer.future;
   }
 
   @override
-  Future<UserPlan> getCurrentPlan() async {
-    final value = _prefs.getString(_key);
-    return value == 'vip' ? UserPlan.vip : UserPlan.free;
+  Future<PurchaseResult> restorePurchases() async {
+    final available = await _inAppPurchase.isAvailable();
+    if (!available) {
+      return PurchaseResult.failed('Billing not available');
+    }
+
+    await _inAppPurchase.restorePurchases();
+
+    final completer = Completer<PurchaseResult>();
+    late StreamSubscription sub;
+    sub = purchaseStream.timeout(
+      const Duration(seconds: 15),
+      onTimeout: (sink) {
+        if (!completer.isCompleted) {
+          completer.complete(PurchaseResult.failed('Restore timed out'));
+        }
+        sub.cancel();
+      },
+    ).listen((purchases) {
+      for (final p in purchases) {
+        if (p.productID == BillingService.proProductId &&
+            (p.status == PurchaseStatus.restored ||
+                p.status == PurchaseStatus.purchased)) {
+          if (!completer.isCompleted) {
+            completer.complete(PurchaseResult.ok(p.verificationData.serverVerificationData));
+          }
+          sub.cancel();
+          return;
+        }
+      }
+    });
+
+    return completer.future;
+  }
+
+  @override
+  Future<PurchaseResult> queryPastPurchase() async {
+    final available = await _inAppPurchase.isAvailable();
+    if (!available) {
+      return const PurchaseResult();
+    }
+
+    final response = await _inAppPurchase.queryProductDetails(
+      {BillingService.proProductId},
+    );
+    if (response.productDetails.isEmpty) {
+      return const PurchaseResult();
+    }
+
+    final completer = Completer<PurchaseResult>();
+    late StreamSubscription sub;
+    sub = purchaseStream.timeout(
+      const Duration(seconds: 10),
+      onTimeout: (sink) {
+        if (!completer.isCompleted) {
+          completer.complete(const PurchaseResult());
+        }
+        sub.cancel();
+      },
+    ).listen((purchases) {
+      for (final p in purchases) {
+        if (p.productID == BillingService.proProductId &&
+            (p.status == PurchaseStatus.restored ||
+                p.status == PurchaseStatus.purchased)) {
+          if (!completer.isCompleted) {
+            completer.complete(PurchaseResult.ok(p.verificationData.serverVerificationData));
+          }
+          sub.cancel();
+          return;
+        }
+      }
+    });
+
+    await _inAppPurchase.restorePurchases();
+
+    return completer.future;
+  }
+
+  @override
+  Future<void> completePurchase(String purchaseToken) async {
+    if (kDebugMode) {
+      print('completePurchase: $purchaseToken');
+    }
+  }
+
+  @override
+  Future<void> dispose() async {
+    await _sub.cancel();
+    await _controller.close();
   }
 }

lib/shared/services/google_auth_service.dart

@@ -4,7 +4,10 @@ import 'package:google_sign_in/google_sign_in.dart';
 class GoogleAuthService {
   final GoogleSignIn _googleSignIn;
 
-  GoogleAuthService() : _googleSignIn = GoogleSignIn(scopes: ['email']);
+  GoogleAuthService() : _googleSignIn = GoogleSignIn(scopes: [
+    'email',
+    'https://www.googleapis.com/auth/drive.appdata',
+  ]);
 
   GoogleSignInAccount? get currentUser => _googleSignIn.currentUser;
 

lib/shared/services/google_drive_service.dart

@@ -0,0 +1,147 @@
+import 'dart:typed_data';
+import 'package:googleapis/drive/v3.dart' as drive;
+import 'package:google_sign_in/google_sign_in.dart';
+import 'package:extension_google_sign_in_as_googleapis_auth/extension_google_sign_in_as_googleapis_auth.dart';
+
+class DriveBackupResult {
+  final bool success;
+  final String? error;
+  final String? fileId;
+  final DateTime? modifiedTime;
+
+  const DriveBackupResult({this.success = false, this.error, this.fileId, this.modifiedTime});
+
+  factory DriveBackupResult.ok(String fileId, DateTime modifiedTime) =>
+      DriveBackupResult(success: true, fileId: fileId, modifiedTime: modifiedTime);
+
+  factory DriveBackupResult.failed(String error) =>
+      DriveBackupResult(success: false, error: error);
+}
+
+class GoogleDriveService {
+  static const _fileName = 'casha_backup.json';
+  static const _appDataFolder = 'appDataFolder';
+
+  final GoogleSignIn _googleSignIn;
+
+  GoogleDriveService(this._googleSignIn);
+
+  GoogleSignInAccount? get currentUser => _googleSignIn.currentUser;
+  Stream<GoogleSignInAccount?> get onUserChanged => _googleSignIn.onCurrentUserChanged;
+
+  Future<void> signIn() async {
+    await _googleSignIn.signIn();
+  }
+
+  Future<void> signOut() async {
+    await _googleSignIn.signOut();
+  }
+
+  Future<drive.DriveApi?> _getDriveApi() async {
+    if (_googleSignIn.currentUser == null) return null;
+    final httpClient = await _googleSignIn.authenticatedClient();
+    if (httpClient == null) return null;
+    return drive.DriveApi(httpClient);
+  }
+
+  Future<String?> _findExistingFile(drive.DriveApi api) async {
+    final list = await api.files.list(
+      spaces: _appDataFolder,
+      q: "name = '$_fileName' and trashed = false",
+      $fields: 'files(id, name, modifiedTime)',
+    );
+    return list.files?.isNotEmpty == true ? list.files!.first.id : null;
+  }
+
+  Future<DriveBackupResult> uploadBackup(Uint8List data) async {
+    final api = await _getDriveApi();
+    if (api == null) {
+      return DriveBackupResult.failed('Not authenticated');
+    }
+
+    try {
+      final existingId = await _findExistingFile(api);
+
+      final media = drive.Media(
+        Stream<List<int>>.fromIterable([data.toList()]),
+        data.length,
+      );
+
+      if (existingId != null) {
+        final file = drive.File(
+          name: _fileName,
+          modifiedTime: DateTime.now(),
+        );
+        final updated = await api.files.update(
+          file,
+          existingId,
+          uploadMedia: media,
+          $fields: 'id, modifiedTime',
+        );
+        return DriveBackupResult.ok(
+          updated.id!,
+          updated.modifiedTime!,
+        );
+      } else {
+        final file = drive.File(
+          name: _fileName,
+          parents: [_appDataFolder],
+          modifiedTime: DateTime.now(),
+        );
+        final created = await api.files.create(
+          file,
+          uploadMedia: media,
+          $fields: 'id, modifiedTime',
+        );
+        return DriveBackupResult.ok(
+          created.id!,
+          created.modifiedTime!,
+        );
+      }
+    } catch (e) {
+      return DriveBackupResult.failed(e.toString());
+    }
+  }
+
+  Future<Uint8List?> downloadBackup() async {
+    final api = await _getDriveApi();
+    if (api == null) return null;
+
+    try {
+      final fileId = await _findExistingFile(api);
+      if (fileId == null) return null;
+
+      final media = await api.files.get(
+        fileId,
+        downloadOptions: drive.DownloadOptions.fullMedia,
+      ) as drive.Media;
+
+      final bytes = <int>[];
+      await for (final chunk in media.stream) {
+        bytes.addAll(chunk);
+      }
+      return Uint8List.fromList(bytes);
+    } catch (e) {
+      return null;
+    }
+  }
+
+  Future<DateTime?> getLastBackupTime() async {
+    final api = await _getDriveApi();
+    if (api == null) return null;
+
+    try {
+      final list = await api.files.list(
+        spaces: _appDataFolder,
+        q: "name = '$_fileName' and trashed = false",
+        $fields: 'files(id, name, modifiedTime)',
+      );
+      if (list.files?.isNotEmpty == true) {
+        return list.files!.first.modifiedTime;
+      }
+      return null;
+    } catch (e) {
+      return null;
+    }
+  }
+}

lib/shared/services/premium_manager.dart

@@ -0,0 +1,58 @@
+import 'package:shared_preferences/shared_preferences.dart';
+import '../models/user_model.dart';
+import 'billing_service.dart';
+
+class PremiumManager {
+  static const _keyIsPremium = 'is_premium';
+  static const _keyPurchaseToken = 'purchase_token';
+
+  final SharedPreferences _prefs;
+  final BillingService _billing;
+
+  PremiumManager(this._prefs, this._billing);
+
+  bool get isPremium => _prefs.getBool(_keyIsPremium) ?? false;
+  String? get purchaseToken => _prefs.getString(_keyPurchaseToken);
+
+  Future<void> _setPremium(bool value, String? token) async {
+    await _prefs.setBool(_keyIsPremium, value);
+    if (token != null) {
+      await _prefs.setString(_keyPurchaseToken, token);
+    } else if (!value) {
+      await _prefs.remove(_keyPurchaseToken);
+    }
+  }
+
+  Future<PurchaseResult> purchase() async {
+    final result = await _billing.purchasePro();
+    if (result.success && result.purchaseToken != null) {
+      await _setPremium(true, result.purchaseToken);
+      await _billing.completePurchase(result.purchaseToken!);
+    }
+    return result;
+  }
+
+  Future<PurchaseResult> restore() async {
+    final result = await _billing.restorePurchases();
+    if (result.success && result.purchaseToken != null) {
+      await _setPremium(true, result.purchaseToken);
+      await _billing.completePurchase(result.purchaseToken!);
+    }
+    return result;
+  }
+
+  Future<void> autoRestore() async {
+    if (isPremium) return;
+    final result = await _billing.queryPastPurchase();
+    if (result.success && result.purchaseToken != null) {
+      await _setPremium(true, result.purchaseToken);
+      await _billing.completePurchase(result.purchaseToken!);
+    }
+  }
+
+  UserPlan get currentPlan => isPremium ? UserPlan.vip : UserPlan.free;
+
+  Future<void> clear() async {
+    await _setPremium(false, null);
+  }
+}

lib/shared/widgets/backup_screen.dart

@@ -0,0 +1,360 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:go_router/go_router.dart';
+import '../../core/l10n/app_strings.dart';
+import '../../core/l10n/locale_provider.dart';
+import '../../core/services/haptic_service.dart';
+import '../providers/backup_provider.dart';
+import '../providers/google_drive_provider.dart';
+import '../providers/premium_provider.dart';
+import 'error_snackbar.dart';
+import '../services/backup_service.dart';
+
+class BackupScreen extends ConsumerStatefulWidget {
+  const BackupScreen({super.key});
+
+  @override
+  ConsumerState<BackupScreen> createState() => _BackupScreenState();
+}
+
+class _BackupScreenState extends ConsumerState<BackupScreen> {
+  bool _backingUp = false;
+  bool _restoring = false;
+  DateTime? _lastBackupTime;
+
+  @override
+  void initState() {
+    super.initState();
+    _loadLastBackupTime();
+  }
+
+  Future<void> _loadLastBackupTime() async {
+    final service = ref.read(googleDriveServiceProvider);
+    final time = await service.getLastBackupTime();
+    if (mounted) {
+      setState(() => _lastBackupTime = time);
+    }
+  }
+
+  Future<void> _handleBackup() async {
+    final s = ref.read(stringsProvider);
+    final driveService = ref.read(googleDriveServiceProvider);
+
+    if (driveService.currentUser == null) {
+      showErrorSnackbar(context, s.backupRequiresSignIn);
+      return;
+    }
+
+    HapticService.light();
+    setState(() => _backingUp = true);
+
+    try {
+      final backupService = ref.read(backupServiceProvider);
+      final payload = <String, dynamic>{
+        'version': 1,
+        'exported_at': DateTime.now().toIso8601String(),
+      };
+      final data = backupService.createBackup(payload);
+      final result = await driveService.uploadBackup(data);
+
+      if (result.success) {
+        setState(() => _lastBackupTime = result.modifiedTime);
+        HapticService.medium();
+        if (mounted) {
+          showSuccessSnackbar(context, s.backupSuccess);
+        }
+      } else {
+        if (mounted) {
+          showErrorSnackbar(context, result.error ?? s.backupRestoreFailed);
+        }
+      }
+    } catch (e) {
+      if (mounted) {
+        showErrorSnackbar(context, e.toString());
+      }
+    } finally {
+      if (mounted) setState(() => _backingUp = false);
+    }
+  }
+
+  Future<void> _handleRestore() async {
+    final s = ref.read(stringsProvider);
+    final driveService = ref.read(googleDriveServiceProvider);
+
+    if (driveService.currentUser == null) {
+      showErrorSnackbar(context, s.backupRequiresSignIn);
+      return;
+    }
+
+    HapticService.light();
+    setState(() => _restoring = true);
+
+    try {
+      final raw = await driveService.downloadBackup();
+      if (raw == null) {
+        if (mounted) {
+          showWarningSnackbar(context, s.backupNoFileFound);
+        }
+        return;
+      }
+
+      final backupService = ref.read(backupServiceProvider);
+      final (result, data) = backupService.verifyAndParse(raw);
+
+      switch (result) {
+        case BackupVerifyResult.ok:
+          HapticService.medium();
+          if (mounted) {
+            showSuccessSnackbar(context, s.backupRestoreSuccess);
+          }
+        case BackupVerifyResult.tokenMismatch:
+          if (mounted) {
+            showErrorSnackbar(context, s.backupTokenMismatch);
+          }
+        case BackupVerifyResult.noToken:
+          if (mounted) {
+            showErrorSnackbar(context, s.backupNoToken);
+          }
+        case BackupVerifyResult.invalidFormat:
+          if (mounted) {
+            showErrorSnackbar(context, s.backupInvalidFormat);
+          }
+      }
+    } catch (e) {
+      if (mounted) {
+        showErrorSnackbar(context, e.toString());
+      }
+    } finally {
+      if (mounted) setState(() => _restoring = false);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final s = ref.watch(stringsProvider);
+    final isPremium = ref.watch(isPremiumProvider);
+    final driveUserAsync = ref.watch(googleDriveUserProvider);
+    final driveUser = driveUserAsync.value;
+    final colorScheme = Theme.of(context).colorScheme;
+
+    return Scaffold(
+      body: SafeArea(
+        child: Column(
+          children: [
+            Padding(
+              padding: const EdgeInsets.fromLTRB(8, 4, 16, 0),
+              child: Row(
+                children: [
+                  IconButton(
+                    icon: const Icon(Icons.arrow_back_rounded),
+                    onPressed: () => context.pop(),
+                  ),
+                  Text(
+                    s.backupTitle,
+                    style: Theme.of(context).textTheme.titleLarge?.copyWith(
+                          fontWeight: FontWeight.w800,
+                        ),
+                  ),
+                ],
+              ),
+            ),
+            Expanded(
+              child: SingleChildScrollView(
+                padding: const EdgeInsets.all(20),
+                child: Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    if (!isPremium) ...[
+                      _buildLockedState(context, s, colorScheme),
+                    ] else ...[
+                      _buildSyncStatus(context, s, colorScheme, driveUser),
+                      const SizedBox(height: 20),
+                      _buildBackupActions(context, s, colorScheme, driveUser),
+                      const SizedBox(height: 20),
+                      _buildLastBackup(context, s, colorScheme),
+                    ],
+                  ],
+                ),
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
+  Widget _buildLockedState(
+    BuildContext context,
+    AppStrings s,
+    ColorScheme colorScheme,
+  ) {
+    return Container(
+      width: double.infinity,
+      padding: const EdgeInsets.all(24),
+      decoration: BoxDecoration(
+        color: colorScheme.surface,
+        borderRadius: BorderRadius.circular(16),
+        border: Border.all(color: colorScheme.outlineVariant),
+      ),
+      child: Column(
+        children: [
+          Icon(Icons.lock_outline_rounded, size: 48, color: colorScheme.primary),
+          const SizedBox(height: 16),
+          Text(
+            s.backupRequiresPremium,
+            style: Theme.of(context).textTheme.titleMedium?.copyWith(
+                  fontWeight: FontWeight.w600,
+                ),
+            textAlign: TextAlign.center,
+          ),
+          const SizedBox(height: 16),
+          FilledButton(
+            onPressed: () => context.push('/pro'),
+            child: Text(s.proBuy),
+          ),
+        ],
+      ),
+    );
+  }
+
+  Widget _buildSyncStatus(
+    BuildContext context,
+    AppStrings s,
+    ColorScheme colorScheme,
+    dynamic driveUser,
+  ) {
+    return Container(
+      width: double.infinity,
+      padding: const EdgeInsets.all(16),
+      decoration: BoxDecoration(
+        color: colorScheme.surface,
+        borderRadius: BorderRadius.circular(16),
+        border: Border.all(color: colorScheme.outlineVariant),
+      ),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Row(
+            children: [
+              Icon(
+                driveUser != null
+                    ? Icons.cloud_done_rounded
+                    : Icons.cloud_off_rounded,
+                color: driveUser != null ? colorScheme.primary : colorScheme.onSurface.withOpacity(0.4),
+                size: 24,
+              ),
+              const SizedBox(width: 12),
+              Expanded(
+                child: Text(
+                  driveUser != null
+                      ? s.proSyncEnabled
+                      : s.backupRequiresSignIn,
+                  style: Theme.of(context).textTheme.titleMedium?.copyWith(
+                        fontWeight: FontWeight.w600,
+                      ),
+                ),
+              ),
+            ],
+          ),
+          if (driveUser != null) ...[
+            const SizedBox(height: 8),
+            Text(
+              driveUser.email,
+              style: Theme.of(context).textTheme.bodySmall?.copyWith(
+                    color: colorScheme.onSurface.withOpacity(0.6),
+                  ),
+            ),
+          ],
+        ],
+      ),
+    );
+  }
+
+  Widget _buildBackupActions(
+    BuildContext context,
+    AppStrings s,
+    ColorScheme colorScheme,
+    dynamic driveUser,
+  ) {
+    final disabled = driveUser == null;
+    return Column(
+      children: [
+        SizedBox(
+          width: double.infinity,
+          child: FilledButton.icon(
+            onPressed: (disabled || _backingUp) ? null : _handleBackup,
+            icon: _backingUp
+                ? SizedBox(
+                    width: 18,
+                    height: 18,
+                    child: CircularProgressIndicator(
+                      strokeWidth: 2,
+                      color: colorScheme.onPrimary,
+                    ),
+                  )
+                : const Icon(Icons.backup_outlined),
+            label: Text(_backingUp ? s.backupCreating : s.backupCreate),
+            style: FilledButton.styleFrom(
+              padding: const EdgeInsets.symmetric(vertical: 14),
+              shape: RoundedRectangleBorder(
+                borderRadius: BorderRadius.circular(12),
+              ),
+            ),
+          ),
+        ),
+        const SizedBox(height: 12),
+        SizedBox(
+          width: double.infinity,
+          child: OutlinedButton.icon(
+            onPressed: (disabled || _restoring) ? null : _handleRestore,
+            icon: _restoring
+                ? SizedBox(
+                    width: 18,
+                    height: 18,
+                    child: CircularProgressIndicator(
+                      strokeWidth: 2,
+                      color: colorScheme.primary,
+                    ),
+                  )
+                : const Icon(Icons.restore_rounded),
+            label: Text(_restoring ? s.backupRestoring : s.backupRestore),
+            style: OutlinedButton.styleFrom(
+              padding: const EdgeInsets.symmetric(vertical: 14),
+              shape: RoundedRectangleBorder(
+                borderRadius: BorderRadius.circular(12),
+              ),
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+
+  Widget _buildLastBackup(
+    BuildContext context,
+    AppStrings s,
+    ColorScheme colorScheme,
+  ) {
+    return Row(
+      children: [
+        Icon(
+          Icons.schedule_rounded,
+          size: 18,
+          color: colorScheme.onSurface.withOpacity(0.5),
+        ),
+        const SizedBox(width: 8),
+        Text(
+          '${s.backupLastBackup}: ${_lastBackupTime != null ? _formatDate(_lastBackupTime!) : s.backupNever}',
+          style: Theme.of(context).textTheme.bodySmall?.copyWith(
+                color: colorScheme.onSurface.withOpacity(0.5),
+              ),
+        ),
+      ],
+    );
+  }
+
+  String _formatDate(DateTime dt) {
+    final d = dt.toLocal();
+    return '${d.day.toString().padLeft(2, '0')}.${d.month.toString().padLeft(2, '0')}.${d.year} ${d.hour.toString().padLeft(2, '0')}:${d.minute.toString().padLeft(2, '0')}';
+  }
+}

lib/shared/widgets/pro_screen.dart

@@ -4,11 +4,9 @@ import 'package:go_router/go_router.dart';
 import '../../core/l10n/app_strings.dart';
 import '../../core/l10n/locale_provider.dart';
 import '../../core/services/haptic_service.dart';
-import '../feature_flags/feature_flags_provider.dart';
-import '../models/user_model.dart';
-import '../providers/billing_provider.dart';
 import '../providers/current_user_provider.dart';
-import '../providers/google_auth_provider.dart';
+import '../providers/google_drive_provider.dart';
+import '../providers/premium_provider.dart';
 import 'error_snackbar.dart';
 
 class ProScreen extends ConsumerStatefulWidget {
@@ -27,9 +25,9 @@ class _ProScreenState extends ConsumerState<ProScreen>
   late final Animation<double> _successScale;
 
   static const _gradientColors = [
-    Color(0xFF1A237E),
-    Color(0xFF6A1B9A),
-    Color(0xFFE65100),
+    Color(0xFF283593),
+    Color(0xFF5E35B1),
+    Color(0xFFD81B60),
   ];
 
   @override
@@ -68,10 +66,9 @@ class _ProScreenState extends ConsumerState<ProScreen>
   @override
   Widget build(BuildContext context) {
     final s = ref.watch(stringsProvider);
-    final flags = ref.watch(featureFlagsProvider);
-    final isVip = flags.maxAccounts != 3;
-    final googleUserAsync = ref.watch(googleCurrentUserProvider);
-    final googleUser = googleUserAsync.value;
+    final isPremium = ref.watch(isPremiumProvider);
+    final driveUserAsync = ref.watch(googleDriveUserProvider);
+    final driveUser = driveUserAsync.value;
     final colorScheme = Theme.of(context).colorScheme;
 
     return Stack(
@@ -88,18 +85,18 @@ class _ProScreenState extends ConsumerState<ProScreen>
                       crossAxisAlignment: CrossAxisAlignment.start,
                       children: [
                         const SizedBox(height: 4),
-                        _buildHeroBanner(context, s, colorScheme, isVip),
+                        _buildHeroBanner(context, s, colorScheme, isPremium),
                         const SizedBox(height: 20),
                         _buildFeatureList(context, s, colorScheme),
                         const SizedBox(height: 16),
-                        if (isVip) ...[
-                          _buildProActiveSection(context, s, colorScheme, googleUser),
+                        if (isPremium) ...[
+                          _buildProActiveSection(context, s, colorScheme, driveUser),
                         ],
                       ],
                     ),
                   ),
                 ),
-                _buildBottomBar(context, s, colorScheme, isVip),
+                _buildBottomBar(context, s, colorScheme, isPremium),
               ],
             ),
           ),
@@ -476,17 +473,17 @@ class _ProScreenState extends ConsumerState<ProScreen>
     HapticService.light();
     setState(() => _purchasing = true);
     try {
-      final billing = ref.read(billingServiceProvider);
-      final success = await billing.purchasePro();
-      if (success) {
-        await ref.read(currentUserProvider.notifier).setPlan(UserPlan.vip);
+      final manager = ref.read(premiumManagerProvider);
+      final result = await manager.purchase();
+      if (result.success) {
+        await ref.read(currentUserProvider.notifier).refreshFromPremium();
         if (mounted) {
           _showSuccessOverlay();
           HapticService.medium();
         }
       } else {
         if (mounted) {
-          showErrorSnackbar(context, ref.read(stringsProvider).proPurchaseFailed);
+          showErrorSnackbar(context, result.error ?? ref.read(stringsProvider).proPurchaseFailed);
         }
       }
     } catch (e) {
@@ -502,10 +499,10 @@ class _ProScreenState extends ConsumerState<ProScreen>
     HapticService.light();
     setState(() => _restoring = true);
     try {
-      final billing = ref.read(billingServiceProvider);
-      final success = await billing.restorePurchases();
-      if (success) {
-        await ref.read(currentUserProvider.notifier).setPlan(UserPlan.vip);
+      final manager = ref.read(premiumManagerProvider);
+      final result = await manager.restore();
+      if (result.success) {
+        await ref.read(currentUserProvider.notifier).refreshFromPremium();
         if (mounted) {
           _showSuccessOverlay();
           HapticService.medium();
@@ -527,7 +524,7 @@ class _ProScreenState extends ConsumerState<ProScreen>
   Future<void> _handleGoogleSignIn() async {
     HapticService.light();
     try {
-      final service = ref.read(googleAuthProvider);
+      final service = ref.read(googleDriveServiceProvider);
       await service.signIn();
     } catch (e) {
       if (mounted) {
@@ -539,7 +536,7 @@ class _ProScreenState extends ConsumerState<ProScreen>
   Future<void> _handleGoogleSignOut() async {
     HapticService.light();
     try {
-      final service = ref.read(googleAuthProvider);
+      final service = ref.read(googleDriveServiceProvider);
       await service.signOut();
     } catch (e) {
       if (mounted) {

lib/shared/widgets/pro_subscription_card.dart

@@ -3,28 +3,27 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import '../../core/l10n/locale_provider.dart';
 import '../../core/services/haptic_service.dart';
-import '../feature_flags/feature_flags_provider.dart';
-import '../providers/google_auth_provider.dart';
+import '../providers/google_drive_provider.dart';
+import '../providers/premium_provider.dart';
 
 class ProSubscriptionCard extends ConsumerWidget {
   const ProSubscriptionCard({super.key});
 
   static const _gradientColors = [
-    Color(0xFF1A237E),
-    Color(0xFF6A1B9A),
-    Color(0xFFE65100),
+    Color(0xFF283593),
+    Color(0xFF5E35B1),
+    Color(0xFFD81B60),
   ];
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final s = ref.watch(stringsProvider);
-    final flags = ref.watch(featureFlagsProvider);
-    final isVip = flags.maxAccounts != 3;
-    final googleUserAsync = ref.watch(googleCurrentUserProvider);
-    final googleUser = googleUserAsync.value;
+    final isPremium = ref.watch(isPremiumProvider);
+    final driveUserAsync = ref.watch(googleDriveUserProvider);
+    final driveUser = driveUserAsync.value;
 
     return Container(
-      padding: const EdgeInsets.all(20),
+      padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 24),
       decoration: BoxDecoration(
         gradient: const LinearGradient(
           begin: Alignment.topLeft,
@@ -39,85 +38,131 @@ class ProSubscriptionCard extends ConsumerWidget {
           Row(
             children: [
               Container(
-                padding: const EdgeInsets.all(10),
+                padding: const EdgeInsets.all(12),
                 decoration: BoxDecoration(
                   color: Colors.white.withOpacity(0.15),
                   borderRadius: BorderRadius.circular(12),
                 ),
                 child: Icon(
-                  isVip ? Icons.verified_rounded : Icons.workspace_premium_rounded,
+                  isPremium
+                      ? Icons.verified_rounded
+                      : Icons.workspace_premium_rounded,
                   color: Colors.white,
-                  size: 24,
+                  size: 28,
                 ),
               ),
-              const SizedBox(width: 12),
+              const SizedBox(width: 14),
               Expanded(
                 child: Column(
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: [
                     Text(
                       s.proTitle,
-                      style: Theme.of(context).textTheme.titleLarge?.copyWith(
-                            fontWeight: FontWeight.w900,
-                            color: Colors.white,
-                          ),
+                      style:
+                          Theme.of(context).textTheme.titleLarge?.copyWith(
+                                fontWeight: FontWeight.w900,
+                                color: Colors.white,
+                              ),
+                    ),
+                    const SizedBox(height: 4),
+                    Text(
+                      isPremium ? s.proActive : s.proSubtitle,
+                      style: isPremium
+                          ? Theme.of(context).textTheme.bodyMedium?.copyWith(
+                                color: Colors.white.withOpacity(0.9),
+                                fontWeight: FontWeight.w600,
+                              )
+                          : Theme.of(context).textTheme.bodySmall?.copyWith(
+                                color: Colors.white.withOpacity(0.7),
+                              ),
                     ),
-                    if (isVip) ...[
-                      const SizedBox(height: 2),
-                      Text(
-                        googleUser != null
-                            ? '${s.proActive} \u2705'
-                            : s.proActive,
-                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
-                              color: Colors.white.withOpacity(0.9),
-                              fontWeight: FontWeight.w600,
-                            ),
-                      ),
-                    ],
                   ],
                 ),
               ),
-              OutlinedButton(
-                onPressed: () {
-                  HapticService.light();
-                  context.push('/pro');
-                },
-                style: OutlinedButton.styleFrom(
-                  foregroundColor: Colors.white,
-                  side: BorderSide(color: Colors.white.withOpacity(0.4), width: 1.5),
-                  padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
-                  shape: RoundedRectangleBorder(
-                    borderRadius: BorderRadius.circular(20),
-                  ),
-                ),
-                child: Text(
-                  s.proAboutPro,
-                  style: const TextStyle(fontWeight: FontWeight.w700),
-                ),
-              ),
             ],
           ),
-          if (isVip && googleUser == null) ...[
-            const SizedBox(height: 14),
-            SizedBox(
-              width: double.infinity,
-              child: OutlinedButton.icon(
-                onPressed: () {
-                  HapticService.light();
-                  ref.read(googleAuthProvider).signIn();
-                },
-                icon: const Icon(Icons.login_rounded, color: Colors.white, size: 18),
-                label: Text(s.proSignInGoogle),
-                style: OutlinedButton.styleFrom(
-                  foregroundColor: Colors.white,
-                  side: BorderSide(color: Colors.white.withOpacity(0.3), width: 1),
-                  padding: const EdgeInsets.symmetric(vertical: 10),
-                  shape: RoundedRectangleBorder(
-                    borderRadius: BorderRadius.circular(12),
+          const SizedBox(height: 16),
+          if (!isPremium) ...[
+            Row(
+              children: [
+                Expanded(
+                  child: OutlinedButton(
+                    onPressed: () {
+                      HapticService.light();
+                      context.push('/pro');
+                    },
+                    style: OutlinedButton.styleFrom(
+                      foregroundColor: Colors.white,
+                      side: BorderSide(
+                          color: Colors.white.withOpacity(0.4), width: 1.5),
+                      padding: const EdgeInsets.symmetric(vertical: 12),
+                      shape: RoundedRectangleBorder(
+                        borderRadius: BorderRadius.circular(12),
+                      ),
+                    ),
+                    child: Text(
+                      s.proAboutPro,
+                      style: const TextStyle(
+                          fontWeight: FontWeight.w700, fontSize: 15),
+                    ),
+                  ),
+                ),
+              ],
+            ),
+          ] else ...[
+            Row(
+              children: [
+                Expanded(
+                  child: OutlinedButton.icon(
+                    onPressed: () {
+                      HapticService.light();
+                      context.push('/backup');
+                    },
+                    icon: Icon(
+                      driveUser != null
+                          ? Icons.cloud_done_rounded
+                          : Icons.cloud_sync_rounded,
+                      color: Colors.white,
+                      size: 20,
+                    ),
+                    label: Text(s.backupSyncWithDrive),
+                    style: OutlinedButton.styleFrom(
+                      foregroundColor: Colors.white,
+                      side: BorderSide(
+                          color: Colors.white.withOpacity(0.4), width: 1.5),
+                      padding: const EdgeInsets.symmetric(vertical: 12),
+                      shape: RoundedRectangleBorder(
+                        borderRadius: BorderRadius.circular(12),
+                      ),
+                    ),
+                  ),
+                ),
+              ],
+            ),
+            if (driveUser == null) ...[
+              const SizedBox(height: 10),
+              SizedBox(
+                width: double.infinity,
+                child: OutlinedButton.icon(
+                  onPressed: () {
+                    HapticService.light();
+                    ref.read(googleDriveServiceProvider).signIn();
+                  },
+                  icon: const Icon(Icons.login_rounded,
+                      color: Colors.white, size: 18),
+                  label: Text(s.proSignInGoogle),
+                  style: OutlinedButton.styleFrom(
+                    foregroundColor: Colors.white,
+                    side: BorderSide(
+                        color: Colors.white.withOpacity(0.3), width: 1),
+                    padding: const EdgeInsets.symmetric(vertical: 10),
+                    shape: RoundedRectangleBorder(
+                      borderRadius: BorderRadius.circular(12),
+                    ),
                   ),
                 ),
               ),
-            ),
+            ],
           ],
         ],
       ),

macos/Flutter/GeneratedPluginRegistrant.swift

@@ -6,11 +6,13 @@ import FlutterMacOS
 import Foundation
 
 import google_sign_in_ios
+import in_app_purchase_storekit
 import local_auth_darwin
 import shared_preferences_foundation
 
 func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
   FLTGoogleSignInPlugin.register(with: registry.registrar(forPlugin: "FLTGoogleSignInPlugin"))
+  InAppPurchasePlugin.register(with: registry.registrar(forPlugin: "InAppPurchasePlugin"))
   LocalAuthPlugin.register(with: registry.registrar(forPlugin: "LocalAuthPlugin"))
   SharedPreferencesPlugin.register(with: registry.registrar(forPlugin: "SharedPreferencesPlugin"))
 }

pubspec.lock

@@ -1,6 +1,14 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  _discoveryapis_commons:
+    dependency: transitive
+    description:
+      name: _discoveryapis_commons
+      sha256: "113c4100b90a5b70a983541782431b82168b3cae166ab130649c36eb3559d498"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.7"
   _fe_analyzer_shared:
     dependency: transitive
     description:
@@ -241,6 +249,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.8"
+  extension_google_sign_in_as_googleapis_auth:
+    dependency: "direct main"
+    description:
+      name: extension_google_sign_in_as_googleapis_auth
+      sha256: "0dcb17e399f62e897ac78f0a402a3cb6ab9313ced8b2bf131f684d317e05c9ab"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.13"
   fake_async:
     dependency: transitive
     description:
@@ -424,6 +440,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.12.4+4"
+  googleapis:
+    dependency: "direct main"
+    description:
+      name: googleapis
+      sha256: "864f222aed3f2ff00b816c675edf00a39e2aaf373d728d8abec30b37bee1a81c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "13.2.0"
+  googleapis_auth:
+    dependency: "direct main"
+    description:
+      name: googleapis_auth
+      sha256: befd71383a955535060acde8792e7efc11d2fccd03dd1d3ec434e85b68775938
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.6.0"
   graphs:
     dependency: transitive
     description:
@@ -480,6 +512,38 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.9.1"
+  in_app_purchase:
+    dependency: "direct main"
+    description:
+      name: in_app_purchase
+      sha256: "0e9510b80b0074e89ab0a8e0fc901439b779dc9ae575ab8d419253c6e1627716"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.3.0"
+  in_app_purchase_android:
+    dependency: transitive
+    description:
+      name: in_app_purchase_android
+      sha256: eb8f551039481d1b265f12fa54f5ab5dd4f13ec5444a468b85a3793517a37fda
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.5.1"
+  in_app_purchase_platform_interface:
+    dependency: transitive
+    description:
+      name: in_app_purchase_platform_interface
+      sha256: "0b0076cac8ce4fa7048f01e76af8b123aeb6a7c4e0dea2a5206d6664454f3e36"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.4.1"
+  in_app_purchase_storekit:
+    dependency: transitive
+    description:
+      name: in_app_purchase_storekit
+      sha256: "5f9d59c86c15f56429a4fdf09097c99d5b412510e1fcf80cf874fc9638fab369"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.4.10"
   intl:
     dependency: "direct main"
     description:

pubspec.yaml

@@ -26,6 +26,10 @@ dependencies:
   sqlite3_flutter_libs: ^0.6.0+eol
   path: ^1.8.3
   google_sign_in: ^6.2.1
+  in_app_purchase: ^3.2.0
+  googleapis: ^13.2.0
+  googleapis_auth: ^1.6.0
+  extension_google_sign_in_as_googleapis_auth: ^2.0.12
 
 flutter_launcher_icons:
   android: true