added oled theme and theme presets

.github/workflows/android.yml

@@ -2,14 +2,9 @@ name: Android CI
 
 on:
   push:
-    branches:
-      - main
-      - develop
-      - issue-*
+    branches: ["main"]
   pull_request:
-    branches:
-      - main
-      - develop
+    branches: ["main"]
 
 jobs:
   build:
@@ -23,7 +18,7 @@ jobs:
 
       # Step 2: Set up JDK 17 with Gradle Caching
       - name: Set up JDK 17
-        uses: actions/setup-java@v5
+        uses: actions/setup-java@v4
         with:
           distribution: "zulu"
           java-version: "17"

.github/workflows/flutter.yml

@@ -0,0 +1,77 @@
+name: Flutter
+
+on:
+  push:
+    paths: ['BalanceFlutter/**', '.github/workflows/flutter.yml', 'Balance/BalanceWatch/**', 'Balance/Balance.xcodeproj/**']
+  pull_request:
+    paths: ['BalanceFlutter/**', '.github/workflows/flutter.yml', 'Balance/BalanceWatch/**', 'Balance/Balance.xcodeproj/**']
+  workflow_dispatch:
+
+env:
+  FLUTTER_VERSION: '3.47.8'
+
+jobs:
+  checks:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: BalanceFlutter
+    steps:
+      - uses: actions/checkout@v4
+      - uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+          flutter-version: ${{ env.FLUTTER_VERSION }}
+          cache: true
+      - run: flutter pub get
+      - run: flutter analyze
+      - run: flutter test
+
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - {platform: web, os: ubuntu-latest, artifact: 'BalanceFlutter/build/web'}
+          - {platform: android, os: ubuntu-latest, artifact: 'BalanceFlutter/build/app/outputs/flutter-apk/*.apk'}
+          - {platform: linux, os: ubuntu-latest, artifact: 'BalanceFlutter/build/linux/x64/release/bundle'}
+          - {platform: windows, os: windows-latest, artifact: 'BalanceFlutter/build/windows/x64/runner/Release'}
+          - {platform: ios, os: macos-latest, artifact: 'BalanceFlutter/build/ios/iphoneos/*.app'}
+          - {platform: macos, os: macos-latest, artifact: 'BalanceFlutter/build/macos/Build/Products/Release/*.app'}
+    runs-on: ${{ matrix.os }}
+    defaults:
+      run:
+        shell: bash
+        working-directory: BalanceFlutter
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        if: matrix.platform == 'android'
+        with:
+          distribution: temurin
+          java-version: '17'
+      - name: Linux dependencies
+        if: matrix.platform == 'linux'
+        run: sudo apt-get update && sudo apt-get install -y clang cmake ninja-build pkg-config libgtk-3-dev libstdc++-12-dev libsecret-1-dev libjsoncpp-dev
+      - uses: subosito/flutter-action@v2
+        with:
+          channel: stable
+          flutter-version: ${{ env.FLUTTER_VERSION }}
+          cache: true
+      - run: bash scripts/build.sh ${{ matrix.platform }}
+      - uses: actions/upload-artifact@v4
+        with:
+          name: balance-${{ matrix.platform }}
+          path: ${{ matrix.artifact }}
+          if-no-files-found: error
+
+  watchos:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: bash BalanceFlutter/scripts/build.sh watchos
+      - uses: actions/upload-artifact@v4
+        with:
+          name: balance-watchos
+          path: BalanceFlutter/build/watchos/Build/Products/*watchsimulator/*.app
+          if-no-files-found: error

.github/workflows/ios.yml

@@ -2,14 +2,9 @@ name: iOS CI
 
 on:
   push:
-    branches:
-      - main
-      - develop
-      - issue-*
+    branches: [ main ]
   pull_request:
-    branches:
-      - main
-      - develop
+    branches: [ main ]
 
 jobs:
   build-and-test:

BalanceFlutter/FEATURE_PARITY.md

@@ -135,3 +135,7 @@ These checks do **not** prove actual Android OS wake-up, force-stop/reboot behav
 The web helper uses SDK `dart:js_interop` only. The audit compiled `scripts/probe_web_lock.dart` to JavaScript and ran it against Node 24's native `navigator.locks`: two separate owner instances serialized, ownership released/reacquired, duplicate acquire/release rejected, insecure origin rejected, unsupported API rejected. The existing three Android channel tests still pass, and targeted analyzer checks pass. This exercises native Web Locks Promise semantics, not a real browser two-tab IndexedDB/keychain scenario; that integration remains an explicit runtime check. The platform owner rebuilds the full release web bundle after this change.
 
 Desktop multiple independent app processes are not coordinated by this Web/Android helper. Standard desktop runners have one foreground AppStore; simultaneous desktop instances require a separately tested OS file-lock implementation before they can be claimed safe.
+
+## Appearance update 4.1
+
+Flutter supports system/light/dark mode plus five persisted presets (forest, indigo, ocean, rose, OLED). Selecting OLED initially enables dark mode; system mode subsequently follows OS brightness. Pure-black surfaces are checked both as theme colors and actual rendered pixels. Total Flutter tests: 62 passing. The native Watch client retains its existing appearance controls.

BalanceFlutter/README.md

@@ -9,13 +9,18 @@
 - Аналитика за 1, 3 и 12 календарных месяцев, доходы/расходы, результат, сбережения, средний расход, крупнейшая категория, динамика и структура расходов.
 - Месячные бюджеты по категориям, остаток и превышение; выбор месяца.
 - Встроенные и собственные категории, 50 значков Material с совместимыми серверными именами, 30 эмодзи и собственный эмодзи, 24 цвета. Переименование обновляет связанные записи; удаление сохраняет историю.
-- RUB, EUR, USD, SEK; системная, светлая и тёмная тема; CSV-экспорт.
+- RUB, EUR, USD, SEK; системная, светлая и тёмная тема; пресеты Лес, Индиго, Океан, Роза и OLED; CSV-экспорт.
+- OLED использует чистый чёрный фон `#000000` в тёмном режиме (включая карточки, навигацию и диалоги). При выборе OLED включается тёмная тема; затем можно выбрать системный режим. Режим и пресет сохраняются локально.
 - Локальная работа без аккаунта; сервер, регистрация, вход, выход, refresh, ручная и автоматическая синхронизация, полная пересинхронизация.
 - Транзакционное сохранение данных и курсора, очередь изменений и удалений, повтор после сетевого сбоя; отдельные хранилища аккаунтов.
 - Адаптивная навигация: нижняя панель на телефоне, боковая на широком экране.
 
 ![Интерфейс на компьютере](docs/desktop.png)
 
+OLED-пресет:
+
+![OLED настройки](docs/oled-settings.png)
+
 ## Платформы
 
 | Платформа | Реализация / сборка |

BalanceFlutter/VALIDATION.md

@@ -29,3 +29,11 @@
 ## Принятые различия
 
 Material 3 и адаптивная навигация; денежные значения в целых сотых (старые доли менее сотой округляются); границы периодов `[start,end)`; отдельные данные аккаунтов; график динамики — пары столбцов. CloudKit удалён по прямому запросу. Финансовые payload, UUID, даты обновления, корректировки, категории, бюджеты и удаления совместимы с исходным сервером.
+
+## Обновление 4.1 — режимы и пресеты
+
+Добавлены Лес, Индиго, Океан, Роза и OLED. Режим (system/light/dark) и пресет сохраняются независимо в локальных настройках. При выборе OLED сначала включается dark; затем разрешено выбрать system. В тёмном OLED все основные Material surfaces, карточки, app bar, навигация и диалоги используют `#000000`, overlay tint отключён.
+
+Общий запуск после изменений: 62 Flutter-теста PASS; анализатор No issues found. Новые проверки: точные цвета OLED, разные акценты пресетов, сохранение/перезапуск, реакция системного режима на OS brightness, выбор на экране 320px и проверка чёрных пикселей снимков 390/1280px.
+
+APK 4.1 использует новый тестовый ключ, поскольку временный ключ предыдущей тестовой сборки не сохранился после смены среды. Прямая установка поверх APK 4.0 с другой подписью невозможна. Перед заменой старой тестовой сборки синхронизируйте её с Go-сервером и убедитесь в сохранности данных. Для последующих сборок ключ 4.1 сохранён отдельно от репозитория и исходного архива. Для публикации нужен собственный release keystore.

BalanceFlutter/lib/domain/appearance.dart

@@ -0,0 +1,15 @@
+/// Device-local appearance preferences; these never enter finance sync payloads.
+enum ColorPreset {
+  forest('forest', 'Лес', 0xff356859),
+  indigo('indigo', 'Индиго', 0xff4f46a5),
+  ocean('ocean', 'Океан', 0xff006b9a),
+  rose('rose', 'Роза', 0xff984563),
+  oled('oled', 'OLED — чёрный', 0xff51bda0);
+
+  const ColorPreset(this.id, this.label, this.seedArgb);
+  final String id, label;
+  final int seedArgb;
+
+  static ColorPreset fromId(String? id) =>
+      values.firstWhere((preset) => preset.id == id, orElse: () => forest);
+}

BalanceFlutter/lib/services/app_store.dart

@@ -7,6 +7,7 @@ import 'package:shared_preferences/shared_preferences.dart';
 import 'package:uuid/uuid.dart';
 
 import '../domain/finance.dart';
+import '../domain/appearance.dart';
 import 'storage.dart';
 import 'runtime_lock.dart';
 import 'sync_api.dart';
@@ -62,6 +63,7 @@ class AppStore extends ChangeNotifier with WidgetsBindingObserver {
   String serverUrl = '';
   String currency = 'RUB';
   String theme = 'system';
+  String themePreset = 'forest';
   AuthSession? session;
   String? sessionPersistenceWarning;
   String get email => session?.email ?? '';
@@ -121,6 +123,7 @@ class AppStore extends ChangeNotifier with WidgetsBindingObserver {
     serverUrl = _preferences!.getString('serverUrl') ?? serverUrl;
     currency = _preferences!.getString('currency') ?? currency;
     theme = _preferences!.getString('theme') ?? theme;
+    themePreset = ColorPreset.fromId(_preferences!.getString('themePreset')).id;
     _deviceId = _preferences!.getString('deviceId') ?? newId();
     await _preferences!.setString('deviceId', _deviceId);
     _storage ??= await LedgerStorage.open();
@@ -147,6 +150,7 @@ class AppStore extends ChangeNotifier with WidgetsBindingObserver {
     }
     currency = _preferences!.getString('currency') ?? 'RUB';
     theme = _preferences!.getString('theme') ?? 'system';
+    themePreset = ColorPreset.fromId(_preferences!.getString('themePreset')).id;
     _deviceId = _preferences!.getString('deviceId') ?? _deviceId;
     await _restoreSession();
     await _loadScope();
@@ -481,10 +485,26 @@ class AppStore extends ChangeNotifier with WidgetsBindingObserver {
     _notify();
   });
   Future<void> setTheme(String value) => _exclusive(() async {
+    if (!const ['system', 'light', 'dark'].contains(value)) {
+      throw ArgumentError('Неизвестный режим темы');
+    }
     theme = value;
     await _preferences!.setString('theme', value);
     _notify();
   });
+  Future<void> setThemePreset(String value) => _exclusive(() async {
+    if (!ColorPreset.values.any((preset) => preset.id == value)) {
+      throw ArgumentError('Неизвестный пресет');
+    }
+    await _preferences!.setString('themePreset', value);
+    themePreset = value;
+    if (value == ColorPreset.oled.id) {
+      await _preferences!.setString('theme', 'dark');
+      theme = 'dark';
+    }
+    _notify();
+  });
+
   Future<void> setServerUrl(String value) => _exclusive(() async {
     final normalized = value.trim().replaceAll(RegExp(r'/+$'), '');
     final uri = Uri.tryParse(normalized);

BalanceFlutter/lib/ui/app.dart

@@ -6,6 +6,8 @@ import 'package:intl/intl.dart';
 import 'package:file_selector/file_selector.dart';
 import 'package:share_plus/share_plus.dart';
 import '../domain/finance.dart';
+import '../domain/appearance.dart';
+import 'app_theme.dart';
 import '../services/app_store.dart';
 import 'design.dart';
 import 'editors.dart';
@@ -22,8 +24,14 @@ class BalanceApp extends StatelessWidget {
       locale: const Locale('ru'),
       supportedLocales: const [Locale('ru'), Locale('en')],
       localizationsDelegates: GlobalMaterialLocalizations.delegates,
-      theme: makeTheme(Brightness.light),
-      darkTheme: makeTheme(Brightness.dark),
+      theme: BalanceThemes.build(
+        Brightness.light,
+        ColorPreset.fromId(store.themePreset),
+      ),
+      darkTheme: BalanceThemes.build(
+        Brightness.dark,
+        ColorPreset.fromId(store.themePreset),
+      ),
       themeMode: store.theme == 'dark'
           ? ThemeMode.dark
           : store.theme == 'light'
@@ -34,28 +42,6 @@ class BalanceApp extends StatelessWidget {
           : const Scaffold(body: Center(child: CircularProgressIndicator())),
     ),
   );
-  ThemeData makeTheme(Brightness brightness) {
-    final scheme = ColorScheme.fromSeed(
-      seedColor: const Color(0xff356859),
-      brightness: brightness,
-    );
-    return ThemeData(
-      useMaterial3: true,
-      fontFamily: 'BalanceRoboto',
-      colorScheme: scheme,
-      scaffoldBackgroundColor: scheme.surface,
-      inputDecorationTheme: const InputDecorationTheme(
-        border: OutlineInputBorder(),
-      ),
-      cardTheme: CardThemeData(
-        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
-      ),
-      appBarTheme: AppBarTheme(
-        backgroundColor: scheme.surface,
-        centerTitle: false,
-      ),
-    );
-  }
 }
 
 class BalanceShell extends StatefulWidget {
@@ -1105,6 +1091,7 @@ class _BalanceShellState extends State<BalanceShell> {
           ),
           const SizedBox(height: 16),
           DropdownButtonFormField<String>(
+            key: ValueKey('theme-mode-${store.theme}'),
             initialValue: store.theme,
             decoration: const InputDecoration(labelText: 'Тема'),
             items: const [
@@ -1116,6 +1103,45 @@ class _BalanceShellState extends State<BalanceShell> {
               if (v != null) run(() => store.setTheme(v));
             },
           ),
+          const SizedBox(height: 20),
+          Text(
+            'Цветовой пресет',
+            style: Theme.of(context).textTheme.titleSmall,
+          ),
+          const SizedBox(height: 10),
+          Wrap(
+            spacing: 8,
+            runSpacing: 8,
+            children: ColorPreset.values
+                .map(
+                  (preset) => ChoiceChip(
+                    label: Text(preset.label),
+                    avatar: CircleAvatar(
+                      radius: 9,
+                      backgroundColor: preset == ColorPreset.oled
+                          ? Colors.black
+                          : Color(preset.seedArgb),
+                      child: preset == ColorPreset.oled
+                          ? const Icon(
+                              Icons.nightlight_round,
+                              size: 13,
+                              color: Colors.white,
+                            )
+                          : null,
+                    ),
+                    selected: store.themePreset == preset.id,
+                    onSelected: (_) =>
+                        run(() => store.setThemePreset(preset.id)),
+                  ),
+                )
+                .toList(),
+          ),
+          if (store.themePreset == 'oled') ...[
+            const SizedBox(height: 12),
+            const Text(
+              'OLED: чистый чёрный фон #000000 в тёмном режиме. При выборе пресета тёмная тема включается автоматически. Можно затем выбрать системный режим.',
+            ),
+          ],
           const SizedBox(height: 12),
           Text(
             'Валюта задаёт формат сумм. Конвертация валют не выполняется.',
@@ -1288,7 +1314,7 @@ class _BalanceShellState extends State<BalanceShell> {
                 onPressed: () => showAboutDialog(
                   context: context,
                   applicationName: 'Баланс',
-                  applicationVersion: '4.0.0',
+                  applicationVersion: '4.1.0',
                   applicationIcon: const Icon(
                     Icons.account_balance_wallet_outlined,
                     size: 40,

BalanceFlutter/lib/ui/app_theme.dart

@@ -0,0 +1,65 @@
+import 'package:flutter/material.dart';
+import '../domain/appearance.dart';
+
+class BalanceThemes {
+  static ThemeData build(Brightness brightness, ColorPreset preset) {
+    final oled = brightness == Brightness.dark && preset == ColorPreset.oled;
+    var scheme = ColorScheme.fromSeed(
+      seedColor: Color(preset.seedArgb),
+      brightness: brightness,
+    );
+    if (oled) {
+      scheme = scheme.copyWith(
+        surface: Colors.black,
+        surfaceDim: Colors.black,
+        surfaceBright: Colors.black,
+        surfaceContainerLowest: Colors.black,
+        surfaceContainerLow: Colors.black,
+        surfaceContainer: Colors.black,
+        surfaceContainerHigh: Colors.black,
+        surfaceContainerHighest: Colors.black,
+        surfaceTint: Colors.transparent,
+        primaryContainer: Colors.black,
+        onPrimaryContainer: scheme.onSurface,
+        secondaryContainer: const Color(0xff171b19),
+        outlineVariant: const Color(0xff303633),
+      );
+    }
+    return ThemeData(
+      useMaterial3: true,
+      fontFamily: 'BalanceRoboto',
+      colorScheme: scheme,
+      scaffoldBackgroundColor: scheme.surface,
+      canvasColor: scheme.surface,
+      applyElevationOverlayColor: !oled,
+      inputDecorationTheme: const InputDecorationTheme(
+        border: OutlineInputBorder(),
+      ),
+      cardTheme: CardThemeData(
+        surfaceTintColor: oled ? Colors.transparent : null,
+        shape: RoundedRectangleBorder(
+          borderRadius: BorderRadius.circular(24),
+          side: oled
+              ? BorderSide(color: scheme.outlineVariant)
+              : BorderSide.none,
+        ),
+      ),
+      appBarTheme: AppBarTheme(
+        backgroundColor: scheme.surface,
+        surfaceTintColor: oled ? Colors.transparent : null,
+        centerTitle: false,
+      ),
+      navigationBarTheme: NavigationBarThemeData(
+        backgroundColor: oled ? Colors.black : null,
+        surfaceTintColor: oled ? Colors.transparent : null,
+      ),
+      navigationRailTheme: NavigationRailThemeData(
+        backgroundColor: oled ? Colors.black : null,
+      ),
+      dialogTheme: DialogThemeData(
+        backgroundColor: oled ? Colors.black : null,
+        surfaceTintColor: oled ? Colors.transparent : null,
+      ),
+    );
+  }
+}

BalanceFlutter/pubspec.yaml

@@ -1,7 +1,7 @@
 name: balance_flutter
 description: Local-first personal finance with BalanceServer synchronization.
 publish_to: none
-version: 4.0.0+1
+version: 4.1.0+2
 environment:
   sdk: '>=3.8.0 <4.0.0'
 dependencies:

BalanceFlutter/test/appearance_test.dart

@@ -0,0 +1,140 @@
+import 'package:balance_flutter/domain/appearance.dart';
+import 'package:balance_flutter/services/app_store.dart';
+import 'package:balance_flutter/services/storage.dart';
+import 'package:balance_flutter/ui/app_theme.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'widget_test.dart' as fixtures;
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  setUp(fixtures.mockStorage);
+
+  test('OLED uses pure black for surfaces, cards, navigation and dialogs', () {
+    final theme = BalanceThemes.build(Brightness.dark, ColorPreset.oled);
+    final scheme = theme.colorScheme;
+    expect(theme.brightness, Brightness.dark);
+    for (final surface in [
+      theme.scaffoldBackgroundColor,
+      theme.canvasColor,
+      scheme.surface,
+      scheme.surfaceDim,
+      scheme.surfaceBright,
+      scheme.surfaceContainerLowest,
+      scheme.surfaceContainerLow,
+      scheme.surfaceContainer,
+      scheme.surfaceContainerHigh,
+      scheme.surfaceContainerHighest,
+      scheme.primaryContainer,
+      theme.appBarTheme.backgroundColor,
+      theme.navigationBarTheme.backgroundColor,
+      theme.navigationRailTheme.backgroundColor,
+      theme.dialogTheme.backgroundColor,
+    ]) {
+      expect(surface, Colors.black);
+    }
+    expect(theme.cardTheme.surfaceTintColor, Colors.transparent);
+    expect(theme.applyElevationOverlayColor, isFalse);
+    expect(scheme.onSurface.computeLuminance(), greaterThan(.6));
+    expect(scheme.primary.computeLuminance(), greaterThan(.3));
+  });
+
+  test('presets have distinct accents and preserve light/dark mode', () {
+    final accents = <Color>{};
+    for (final preset in ColorPreset.values) {
+      final light = BalanceThemes.build(Brightness.light, preset);
+      final dark = BalanceThemes.build(Brightness.dark, preset);
+      expect(light.brightness, Brightness.light);
+      expect(dark.brightness, Brightness.dark);
+      expect(light.scaffoldBackgroundColor, isNot(Colors.black));
+      accents.add(light.colorScheme.primary);
+    }
+    expect(accents.length, ColorPreset.values.length);
+  });
+
+  test(
+    'preset and mode survive restart; OLED initially selects dark',
+    () async {
+      final storage = MemorySnapshotStorage();
+      final store = AppStore(storage: storage, background: true);
+      await store.initialize();
+      expect(store.themePreset, 'forest');
+      expect(store.theme, 'system');
+      await store.setTheme('light');
+      await store.setThemePreset('oled');
+      expect(store.theme, 'dark');
+      await store.setTheme('system');
+      final reopened = AppStore(storage: storage, background: true);
+      await reopened.initialize();
+      expect(reopened.themePreset, 'oled');
+      expect(reopened.theme, 'system');
+      await reopened.setThemePreset('rose');
+      expect(reopened.theme, 'system');
+      await expectLater(
+        reopened.setThemePreset('unknown'),
+        throwsArgumentError,
+      );
+      await store.close();
+      await reopened.close();
+      store.dispose();
+      reopened.dispose();
+    },
+  );
+
+  testWidgets('system mode responds to OS brightness with OLED selected', (
+    tester,
+  ) async {
+    final store = (await tester.runAsync(
+      () => fixtures.createStore(seeded: false),
+    ))!;
+    await tester.runAsync(() async {
+      await store.setThemePreset('oled');
+      await store.setTheme('system');
+    });
+    tester.platformDispatcher.platformBrightnessTestValue = Brightness.dark;
+    addTearDown(tester.platformDispatcher.clearPlatformBrightnessTestValue);
+    await fixtures.boot(tester, store, const Size(390, 844));
+    ThemeData theme() => Theme.of(tester.element(find.byType(Scaffold).first));
+    expect(theme().scaffoldBackgroundColor, Colors.black);
+    tester.platformDispatcher.platformBrightnessTestValue = Brightness.light;
+    await tester.pumpAndSettle();
+    expect(theme().brightness, Brightness.light);
+    expect(theme().scaffoldBackgroundColor, isNot(Colors.black));
+    await tester.runAsync(() => store.setTheme('dark'));
+    await tester.pumpAndSettle();
+    expect(theme().scaffoldBackgroundColor, Colors.black);
+  });
+
+  testWidgets(
+    'OLED can be selected in narrow settings and updates mode control',
+    (tester) async {
+      await fixtures.loadReadableFont();
+      final store = (await tester.runAsync(
+        () => fixtures.createStore(seeded: false),
+      ))!;
+      await fixtures.boot(tester, store, const Size(320, 568));
+      await fixtures.navigate(tester, 4);
+      final oled = find.widgetWithText(ChoiceChip, 'OLED — чёрный');
+      await tester.ensureVisible(oled);
+      await tester.pumpAndSettle();
+      await tester.tap(oled);
+      await tester.runAsync(() async {
+        await Future<void>.delayed(const Duration(milliseconds: 50));
+      });
+      await tester.pumpAndSettle();
+      expect(store.themePreset, 'oled');
+      expect(store.theme, 'dark');
+      expect(
+        tester.widget<MaterialApp>(find.byType(MaterialApp)).themeMode,
+        ThemeMode.dark,
+      );
+      expect(
+        Theme.of(
+          tester.element(find.byType(Scaffold).first),
+        ).scaffoldBackgroundColor,
+        Colors.black,
+      );
+      expect(tester.takeException(), isNull);
+    },
+  );
+}

BalanceFlutter/test/oled_preview_test.dart

@@ -0,0 +1,44 @@
+import 'dart:io';
+import 'dart:ui' as ui;
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'widget_test.dart' as fixtures;
+
+void main() {
+  setUpAll(fixtures.loadReadableFont);
+  setUp(fixtures.mockStorage);
+  for (final size in [const Size(390, 844), const Size(1280, 900)]) {
+    testWidgets('OLED renders black pixels at $size', (tester) async {
+      final store = (await tester.runAsync(() => fixtures.createStore()))!;
+      await tester.runAsync(() => store.setThemePreset('oled'));
+      final key = GlobalKey();
+      await fixtures.boot(tester, store, size, boundaryKey: key);
+      for (final page in [0, 4]) {
+        await fixtures.navigate(tester, page);
+        await tester.runAsync(() async {
+          final boundary =
+              key.currentContext!.findRenderObject()! as RenderRepaintBoundary;
+          final image = await boundary.toImage(pixelRatio: 1);
+          final rgba = await image.toByteData(
+            format: ui.ImageByteFormat.rawRgba,
+          );
+          // Left edge of the scaffold/rail below the app bar, away from text.
+          final pixel = (110 * image.width) * 4;
+          expect(rgba!.getUint8(pixel), 0);
+          expect(rgba.getUint8(pixel + 1), 0);
+          expect(rgba.getUint8(pixel + 2), 0);
+          expect(rgba.getUint8(pixel + 3), 255);
+          final png = await image.toByteData(format: ui.ImageByteFormat.png);
+          final dir = Directory('/tmp/balance-oled-preview')
+            ..createSync(recursive: true);
+          File(
+            '${dir.path}/${size.width.toInt()}-${page == 0 ? 'overview' : 'settings'}.png',
+          ).writeAsBytesSync(png!.buffer.asUint8List());
+          image.dispose();
+        });
+        expect(tester.takeException(), isNull);
+      }
+    });
+  }
+}