feat(flutter): 应用克莱因蓝主题与印尼语适配

lib/core/config/locale_controller.dart

@@ -3,6 +3,19 @@
 import 'package:flutter/widgets.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
+/// Resolves the selected or system language to one of the supported app locales.
+///
+/// Indonesian is the launch-market fallback when a device uses an unsupported
+/// language. The legacy `in` code is treated as Indonesian as well.
+Locale resolveAppLocale(Locale? selected, Locale? deviceLocale) {
+  final code = (selected ?? deviceLocale)?.languageCode;
+  return switch (code) {
+    'zh' => const Locale('zh'),
+    'en' => const Locale('en'),
+    _ => const Locale('id'),
+  };
+}
+
 class LocaleController extends ChangeNotifier {
   LocaleController({SharedPreferencesAsync? preferences})
     : _preferences = preferences ?? SharedPreferencesAsync();
@@ -17,6 +30,7 @@ class LocaleController extends ChangeNotifier {
       _locale = switch (code) {
         'en' => const Locale('en'),
         'zh' => const Locale('zh'),
+        'id' => const Locale('id'),
         _ => null,
       };
       notifyListeners();
@@ -29,6 +43,7 @@ class LocaleController extends ChangeNotifier {
     _locale = switch (code) {
       'en' => const Locale('en'),
       'zh' => const Locale('zh'),
+      'id' => const Locale('id'),
       _ => null,
     };
     notifyListeners();

lib/core/formatting/localized_date_time.dart

@@ -0,0 +1,15 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/material.dart';
+
+/// Formats a timestamp with the active Material locale and 12/24-hour setting.
+String formatLocalizedDateTime(BuildContext context, DateTime value) {
+  final localizations = MaterialLocalizations.of(context);
+  final local = value.toLocal();
+  final date = localizations.formatCompactDate(local);
+  final time = localizations.formatTimeOfDay(
+    TimeOfDay.fromDateTime(local),
+    alwaysUse24HourFormat: MediaQuery.alwaysUse24HourFormatOf(context),
+  );
+  return '$date $time';
+}

lib/core/theme/app_colors.dart

@@ -2,8 +2,17 @@ import 'package:flutter/material.dart';
 
 /// Shared colors. Blue is the primary action color.
 abstract final class AppColors {
-  static const blue = Color(0xFF2F7BFF);
-  static const blueSoft = Color(0xFF8FB4FF);
+  /// Klein Blue primary used by actions and selected states.
+  static const blue = Color(0xFF002FA7);
+
+  /// Pressed/active shade for blue surfaces.
+  static const bluePressed = Color(0xFF00227A);
+
+  /// High-contrast blue for text and icons on dark surfaces.
+  static const blueSoft = Color(0xFF5B7BE0);
+
+  /// Text and icons placed directly on [blue].
+  static const onPrimary = Color(0xFFFFFFFF);
   static const ink = Color(0xFF0B0C10);
   static const bar = Color(0xFF101114);
   static const card = Color(0xFF17191F);

lib/core/theme/app_theme.dart

@@ -0,0 +1,106 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/material.dart';
+
+import 'app_colors.dart';
+
+/// App-wide light and dark themes built from the approved Klein Blue palette.
+abstract final class AppTheme {
+  static const _lightBackground = Color(0xFFF8F7FC);
+  static const _darkBackground = Color(0xFF101019);
+
+  /// Light theme for system light mode.
+  static ThemeData light() => _build(
+    brightness: Brightness.light,
+    surface: _lightBackground,
+    accent: AppColors.blue,
+  );
+
+  /// Dark theme for system dark mode.
+  static ThemeData dark() => _build(
+    brightness: Brightness.dark,
+    surface: _darkBackground,
+    accent: AppColors.blueSoft,
+  );
+
+  static ThemeData _build({
+    required Brightness brightness,
+    required Color surface,
+    required Color accent,
+  }) {
+    final dark = brightness == Brightness.dark;
+    final scheme = dark
+        ? const ColorScheme.dark(
+            primary: AppColors.blue,
+            onPrimary: AppColors.onPrimary,
+            secondary: AppColors.blueSoft,
+            onSecondary: AppColors.ink,
+            primaryContainer: AppColors.bluePressed,
+            onPrimaryContainer: AppColors.onPrimary,
+            secondaryContainer: AppColors.bluePressed,
+            onSecondaryContainer: AppColors.onPrimary,
+            surface: _darkBackground,
+            onSurface: Colors.white,
+            surfaceTint: AppColors.blueSoft,
+            inversePrimary: AppColors.blueSoft,
+          )
+        : ColorScheme.light(
+            primary: AppColors.blue,
+            onPrimary: AppColors.onPrimary,
+            secondary: AppColors.blue,
+            onSecondary: AppColors.onPrimary,
+            primaryContainer: AppColors.blueSoft.withValues(alpha: 0.22),
+            onPrimaryContainer: AppColors.ink,
+            secondaryContainer: AppColors.blueSoft.withValues(alpha: 0.22),
+            onSecondaryContainer: AppColors.ink,
+            surface: _lightBackground,
+            onSurface: AppColors.ink,
+            surfaceTint: AppColors.blue,
+            inversePrimary: AppColors.blueSoft,
+          );
+    return ThemeData(
+      useMaterial3: true,
+      brightness: brightness,
+      colorScheme: scheme,
+      scaffoldBackgroundColor: surface,
+      progressIndicatorTheme: ProgressIndicatorThemeData(color: accent),
+      sliderTheme: SliderThemeData(
+        activeTrackColor: accent,
+        thumbColor: AppColors.onPrimary,
+      ),
+      tabBarTheme: TabBarThemeData(labelColor: accent, indicatorColor: accent),
+      textButtonTheme: TextButtonThemeData(
+        style: TextButton.styleFrom(foregroundColor: accent),
+      ),
+      filledButtonTheme: FilledButtonThemeData(
+        style: ButtonStyle(
+          backgroundColor: WidgetStateProperty.resolveWith(_buttonColor),
+          foregroundColor: const WidgetStatePropertyAll(AppColors.onPrimary),
+        ),
+      ),
+      switchTheme: SwitchThemeData(
+        thumbColor: WidgetStateProperty.resolveWith(
+          (states) => states.contains(WidgetState.selected)
+              ? AppColors.onPrimary
+              : null,
+        ),
+        trackColor: WidgetStateProperty.resolveWith(
+          (states) => states.contains(WidgetState.selected) ? accent : null,
+        ),
+      ),
+      snackBarTheme: SnackBarThemeData(
+        backgroundColor: AppColors.bluePressed,
+        contentTextStyle: const TextStyle(color: AppColors.onPrimary),
+      ),
+    );
+  }
+
+  static Color _buttonColor(Set<WidgetState> states) {
+    if (states.contains(WidgetState.pressed) ||
+        states.contains(WidgetState.hovered) ||
+        states.contains(WidgetState.focused)) {
+      return AppColors.bluePressed;
+    }
+    return AppColors.blue;
+  }
+}