feat(appearance): manual toggle to force backdrop blur on lower device tiers

lib/l10n/app_localizations.dart

@@ -2914,6 +2914,18 @@ abstract class AppLocalizations {
   /// **'Fly covers between screens, e.g. when opening the player'**
   String get appearanceHeroAnimationsSubtitle;
 
+  /// Toggle that forces backdrop blur on even when the device profile disabled it
+  ///
+  /// In en, this message translates to:
+  /// **'Always use blur effects'**
+  String get appearanceForceBlur;
+
+  /// Subtitle for the force-blur toggle
+  ///
+  /// In en, this message translates to:
+  /// **'Enable the navigation bar blur even on devices where it is off by default. May cost performance.'**
+  String get appearanceForceBlurSubtitle;
+
   /// Button - clear all queue items
   ///
   /// In en, this message translates to:

lib/l10n/app_localizations_de.dart

@@ -1598,6 +1598,13 @@ class AppLocalizationsDe extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Alles löschen';
 

lib/l10n/app_localizations_en.dart

@@ -1576,6 +1576,13 @@ class AppLocalizationsEn extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Clear All';
 

lib/l10n/app_localizations_es.dart

@@ -1576,6 +1576,13 @@ class AppLocalizationsEs extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Clear All';
 

lib/l10n/app_localizations_fr.dart

@@ -1620,6 +1620,13 @@ class AppLocalizationsFr extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Des fenêtres contextuelles apparaissent entre les écrans, par exemple lors de l\'ouverture du lecteur';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Tout effacer';
 

lib/l10n/app_localizations_id.dart

@@ -1585,6 +1585,13 @@ class AppLocalizationsId extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Hapus Semua';
 

lib/l10n/app_localizations_ja.dart

@@ -1567,6 +1567,13 @@ class AppLocalizationsJa extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'すべて消去';
 

lib/l10n/app_localizations_ko.dart

@@ -1543,6 +1543,13 @@ class AppLocalizationsKo extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       '화면 간 이동 시 표지 이미지가 날아가는 애니메이션을 표시합니다 (예시: 플레이어를 실행할 경우)';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => '모두 지우기';
 

lib/l10n/app_localizations_pt.dart

@@ -1576,6 +1576,13 @@ class AppLocalizationsPt extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Clear All';
 

lib/l10n/app_localizations_ru.dart

@@ -1591,6 +1591,13 @@ class AppLocalizationsRu extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Очистить всё';
 

lib/l10n/app_localizations_tr.dart

@@ -1593,6 +1593,13 @@ class AppLocalizationsTr extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Tümünü Temizle';
 

lib/l10n/app_localizations_uk.dart

@@ -1599,6 +1599,13 @@ class AppLocalizationsUk extends AppLocalizations {
   String get appearanceHeroAnimationsSubtitle =>
       'Fly covers between screens, e.g. when opening the player';
 
+  @override
+  String get appearanceForceBlur => 'Always use blur effects';
+
+  @override
+  String get appearanceForceBlurSubtitle =>
+      'Enable the navigation bar blur even on devices where it is off by default. May cost performance.';
+
   @override
   String get queueClearAll => 'Усі';
 

lib/l10n/arb/app_en.arb

@@ -2091,6 +2091,14 @@
   "@appearanceHeroAnimationsSubtitle": {
     "description": "Subtitle for the Hero animations toggle"
   },
+  "appearanceForceBlur": "Always use blur effects",
+  "@appearanceForceBlur": {
+    "description": "Toggle that forces backdrop blur on even when the device profile disabled it"
+  },
+  "appearanceForceBlurSubtitle": "Enable the navigation bar blur even on devices where it is off by default. May cost performance.",
+  "@appearanceForceBlurSubtitle": {
+    "description": "Subtitle for the force-blur toggle"
+  },
   "queueClearAll": "Clear All",
   "@queueClearAll": {
     "description": "Button - clear all queue items"

lib/main.dart

@@ -56,7 +56,7 @@ void main() {
             lowEndDeviceProvider.overrideWithValue(
               runtimeProfile.disableOverscrollEffects,
             ),
-            backdropBlurEnabledProvider.overrideWithValue(
+            deviceSupportsBackdropBlurProvider.overrideWithValue(
               runtimeProfile.enableBackdropBlur,
             ),
             initialSettingsProvider.overrideWithValue(bootstrapSettings),

lib/models/settings.dart

@@ -49,6 +49,11 @@ class AppSettings {
   /// Shared-element (Hero) flights, e.g. the mini player artwork expanding
   /// into the full player. Off skips the flights entirely.
   final bool heroAnimationsEnabled;
+
+  /// Forces the shell's backdrop blur on even when the startup runtime
+  /// profile disabled it for this device tier. Off means "follow the
+  /// device default".
+  final bool forceBackdropBlur;
   final String
   extensionVerificationBrowserMode; // 'external_first' or 'in_app_first'
   final String locale;
@@ -139,6 +144,7 @@ class AppSettings {
     this.albumFolderStructure = 'artist_album',
     this.showExtensionStore = true,
     this.heroAnimationsEnabled = true,
+    this.forceBackdropBlur = false,
     this.extensionVerificationBrowserMode = 'in_app_first',
     this.locale = 'system',
     this.lyricsMode = 'embed',
@@ -211,6 +217,7 @@ class AppSettings {
     String? albumFolderStructure,
     bool? showExtensionStore,
     bool? heroAnimationsEnabled,
+    bool? forceBackdropBlur,
     String? extensionVerificationBrowserMode,
     String? locale,
     String? lyricsMode,
@@ -293,6 +300,7 @@ class AppSettings {
       showExtensionStore: showExtensionStore ?? this.showExtensionStore,
       heroAnimationsEnabled:
           heroAnimationsEnabled ?? this.heroAnimationsEnabled,
+      forceBackdropBlur: forceBackdropBlur ?? this.forceBackdropBlur,
       extensionVerificationBrowserMode:
           extensionVerificationBrowserMode ??
           this.extensionVerificationBrowserMode,

lib/models/settings.g.dart

@@ -50,6 +50,7 @@ AppSettings _$AppSettingsFromJson(Map<String, dynamic> json) => AppSettings(
       json['albumFolderStructure'] as String? ?? 'artist_album',
   showExtensionStore: json['showExtensionStore'] as bool? ?? true,
   heroAnimationsEnabled: json['heroAnimationsEnabled'] as bool? ?? true,
+  forceBackdropBlur: json['forceBackdropBlur'] as bool? ?? false,
   extensionVerificationBrowserMode:
       json['extensionVerificationBrowserMode'] as String? ?? 'in_app_first',
   locale: json['locale'] as String? ?? 'system',
@@ -133,6 +134,7 @@ Map<String, dynamic> _$AppSettingsToJson(
   'albumFolderStructure': instance.albumFolderStructure,
   'showExtensionStore': instance.showExtensionStore,
   'heroAnimationsEnabled': instance.heroAnimationsEnabled,
+  'forceBackdropBlur': instance.forceBackdropBlur,
   'extensionVerificationBrowserMode': instance.extensionVerificationBrowserMode,
   'locale': instance.locale,
   'lyricsMode': instance.lyricsMode,

lib/providers/runtime_profile_provider.dart

@@ -1,10 +1,19 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:spotiflac_android/providers/settings_provider.dart';
 
 /// True on low-end hardware (arm32-only or low-RAM, resolved at startup in
 /// main.dart via a ProviderScope override). UI uses it to skip expensive
 /// effects like the shell's backdrop blur.
 final lowEndDeviceProvider = Provider<bool>((ref) => false);
 
-/// Generic visual capability decided by the startup runtime profile. Effects
-/// can consume this without hardcoding a device model or platform source.
-final backdropBlurEnabledProvider = Provider<bool>((ref) => false);
+/// Raw device capability decided by the startup runtime profile (overridden
+/// in main.dart). Only the `high` tier enables blur by default.
+final deviceSupportsBackdropBlurProvider = Provider<bool>((ref) => false);
+
+/// Whether backdrop blur effects should render: the device default, or the
+/// user's manual override from appearance settings (issue #488 — let lower
+/// tiers opt back in).
+final backdropBlurEnabledProvider = Provider<bool>((ref) {
+  return ref.watch(deviceSupportsBackdropBlurProvider) ||
+      ref.watch(settingsProvider.select((s) => s.forceBackdropBlur));
+});

lib/providers/settings_provider.dart

@@ -658,6 +658,11 @@ class SettingsNotifier extends Notifier<AppSettings> {
     _saveSettings();
   }
 
+  void setForceBackdropBlur(bool enabled) {
+    state = state.copyWith(forceBackdropBlur: enabled);
+    _saveSettings();
+  }
+
   void setExtensionVerificationBrowserMode(String mode) {
     state = state.copyWith(
       extensionVerificationBrowserMode:

lib/screens/main_shell.dart

@@ -891,8 +891,9 @@ class _MainShellState extends ConsumerState<MainShell>
               ],
             );
             // The backdrop blur re-filters everything scrolling underneath on
-            // every frame; low-end devices get an opaque base instead.
-            if (!ref.read(backdropBlurEnabledProvider)) {
+            // every frame; low-end devices get an opaque base instead unless
+            // the user forces blur on in appearance settings.
+            if (!ref.watch(backdropBlurEnabledProvider)) {
               return ColoredBox(
                 color: settingsGroupColor(context),
                 child: bottomBar,

lib/screens/settings/appearance_settings_page.dart

@@ -101,6 +101,15 @@ class AppearanceSettingsPage extends ConsumerWidget {
                     onChanged: (value) => ref
                         .read(settingsProvider.notifier)
                         .setHeroAnimationsEnabled(value),
+                  ),
+                  SettingsSwitchItem(
+                    icon: Icons.blur_on,
+                    title: context.l10n.appearanceForceBlur,
+                    subtitle: context.l10n.appearanceForceBlurSubtitle,
+                    value: settings.forceBackdropBlur,
+                    onChanged: (value) => ref
+                        .read(settingsProvider.notifier)
+                        .setForceBackdropBlur(value),
                     showDivider: false,
                   ),
                 ],