properly organize custom colors

app/lib/features/geckoview/features/browser/presentation/dialogs/tab_tree.dart

@@ -27,6 +27,7 @@ import 'package:graphview/GraphView.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:nullability/nullability.dart';
 import 'package:skeletonizer/skeletonizer.dart';
+import 'package:weblibre/core/design/app_colors.dart';
 import 'package:weblibre/core/routing/routes.dart';
 import 'package:weblibre/features/geckoview/domain/controllers/bottom_sheet.dart';
 import 'package:weblibre/features/geckoview/domain/providers/selected_tab.dart';
@@ -82,7 +83,7 @@ class TabTreeDialog extends HookConsumerWidget {
     return Dialog.fullscreen(
       child: Scaffold(
         appBar: AppBar(
-          backgroundColor: const Color(0x44000000),
+          backgroundColor: AppColors.dialogOverlay,
           elevation: 0,
           leading: const CloseButton(),
         ),

app/lib/features/geckoview/features/browser/presentation/widgets/browser_modules/app_bar_title.dart

@@ -23,6 +23,7 @@ import 'package:flutter_material_design_icons/flutter_material_design_icons.dart
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:skeletonizer/skeletonizer.dart';
 import 'package:text_scroll/text_scroll.dart';
+import 'package:weblibre/core/design/app_colors.dart';
 import 'package:weblibre/features/geckoview/domain/providers/tab_state.dart';
 import 'package:weblibre/features/geckoview/features/browser/presentation/widgets/tab_icon.dart';
 import 'package:weblibre/presentation/widgets/uri_breadcrumb.dart';
@@ -109,7 +110,7 @@ class AppBarTitle extends HookConsumerWidget {
                   if (tabState.isPrivate) ...[
                     const Icon(
                       MdiIcons.dominoMask,
-                      color: Color(0xFF8000D7),
+                      color: AppColors.privateTabPurple,
                       size: 14,
                     ),
                     const SizedBox(width: 4),

app/lib/features/geckoview/features/browser/presentation/widgets/browser_modules/bottom_app_bar.dart

@@ -25,6 +25,7 @@ import 'package:flutter_material_design_icons/flutter_material_design_icons.dart
 import 'package:flutter_mozilla_components/flutter_mozilla_components.dart';
 import 'package:go_router/go_router.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:weblibre/core/design/app_colors.dart';
 import 'package:weblibre/core/routing/routes.dart';
 import 'package:weblibre/features/geckoview/domain/controllers/bottom_sheet.dart';
 import 'package:weblibre/features/geckoview/domain/entities/states/readerable.dart';
@@ -475,7 +476,7 @@ class QuickTabSwitcher extends HookConsumerWidget {
                     padding: EdgeInsets.only(left: 8.0),
                     child: Icon(
                       MdiIcons.dominoMask,
-                      color: Color(0xFF8000D7),
+                      color: AppColors.privateTabPurple,
                       size: 20,
                     ),
                   ),
@@ -777,7 +778,7 @@ class NavigationMenuButton extends HookConsumerWidget {
 
               return Badge(
                 isLabelVisible: torConnected,
-                backgroundColor: const Color(0xFF68B030),
+                backgroundColor: AppColors.torActiveGreen,
                 child: child,
               );
             },

app/lib/features/geckoview/features/browser/presentation/widgets/tab_view/tab_preview.dart

@@ -24,6 +24,7 @@ import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:flutter_material_design_icons/flutter_material_design_icons.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:nullability/nullability.dart';
+import 'package:weblibre/core/design/app_colors.dart';
 import 'package:weblibre/features/geckoview/domain/entities/states/tab.dart';
 import 'package:weblibre/features/geckoview/domain/providers/tab_state.dart';
 import 'package:weblibre/features/geckoview/domain/repositories/tab.dart';
@@ -61,7 +62,7 @@ class GridTabItemContainer extends StatelessWidget {
       ),
       child: Material(
         color: isPrivate
-            ? const Color(0xFF25003E)
+            ? AppColors.privateTabBackground
             : colorScheme.surfaceContainerHighest,
         borderRadius: const BorderRadius.all(Radius.circular(14.0)),
         child: child,
@@ -193,7 +194,7 @@ class GridTabPreview extends HookConsumerWidget {
                           top: -4,
                           child: Icon(
                             MdiIcons.dominoMask,
-                            color: Color(0xFF8000D7),
+                            color: AppColors.privateTabPurple,
                           ),
                         ),
                       ],
@@ -271,7 +272,7 @@ class ListTabPreview extends HookConsumerWidget {
 
     return Container(
       decoration: BoxDecoration(
-        color: tabState.isPrivate ? const Color(0xFF25003E) : null,
+        color: tabState.isPrivate ? AppColors.privateTabBackground : null,
         border: isActive ? Border.all(color: colorScheme.primary) : null,
         borderRadius: const BorderRadius.all(Radius.circular(4.0)),
       ),
@@ -304,7 +305,7 @@ class ListTabPreview extends HookConsumerWidget {
                   if (tabState.isPrivate) ...[
                     const Icon(
                       MdiIcons.dominoMask,
-                      color: Color(0xFF8000D7),
+                      color: AppColors.privateTabPurple,
                       size: 14,
                     ),
                     const SizedBox(width: 4),