neon, neon_news, neon_notifications: use error color of the theme

packages/neon/neon/lib/src/pages/home.dart

@@ -77,6 +77,8 @@ class _HomePageState extends State<HomePage> {
   }
 
   Future _showProblem(final String title) async {
+    final colorScheme = Theme.of(context).colorScheme;
+
     await showDialog(
       context: context,
       builder: (final context) => AlertDialog(
@@ -84,8 +86,8 @@ class _HomePageState extends State<HomePage> {
         actions: [
           ElevatedButton(
             style: ElevatedButton.styleFrom(
-              backgroundColor: Colors.red,
+              backgroundColor: colorScheme.error,
-              foregroundColor: Theme.of(context).colorScheme.onPrimary,
+              foregroundColor: colorScheme.onError,
             ),
             onPressed: () {
               Navigator.of(context).pop();

packages/neon/neon/lib/src/pages/settings.dart

@@ -118,10 +118,10 @@ class _SettingsPageState extends State<SettingsPage> {
                             !pushNotificationsEnabledEnabledSnapshot.requireData) ...[
                           NeonTextSettingsTile(
                             text: AppLocalizations.of(context).globalOptionsPushNotificationsEnabledDisabledNotice,
-                            style: const TextStyle(
+                            style: TextStyle(
                               fontWeight: FontWeight.w600,
                               fontStyle: FontStyle.italic,
-                              color: Colors.red,
+                              color: Theme.of(context).colorScheme.error,
                             ),
                           ),
                         ],

packages/neon/neon/lib/src/widgets/cached_image.dart

@@ -71,7 +71,7 @@ class _NeonCachedImageState extends State<NeonCachedImage> {
                 },
                 onlyIcon: true,
                 iconSize: widget.size?.shortestSide,
-                color: widget.iconColor ?? Colors.red,
+                color: widget.iconColor ?? Theme.of(context).colorScheme.error,
               );
             }
             return SizedBox(

packages/neon/neon_news/lib/widgets/feeds_view.dart

@@ -74,8 +74,8 @@ class NewsFeedsView extends StatelessWidget {
                 iconSize: 30,
                 icon: Text(
                   feed.updateErrorCount.toString(),
-                  style: const TextStyle(
+                  style: TextStyle(
-                    color: Colors.red,
+                    color: Theme.of(context).colorScheme.error,
                   ),
                 ),
               ),

packages/neon/neon_notifications/lib/pages/main.dart

@@ -92,6 +92,8 @@ class _NotificationsMainPageState extends State<NotificationsMainPage> {
           final accountsBloc = Provider.of<AccountsBloc>(context, listen: false);
           await accountsBloc.activeAppsBloc.setActiveApp(app.id);
         } else {
+          final colorScheme = Theme.of(context).colorScheme;
+
           await showDialog(
             context: context,
             builder: (final context) => AlertDialog(
@@ -99,8 +101,8 @@ class _NotificationsMainPageState extends State<NotificationsMainPage> {
               actions: [
                 ElevatedButton(
                   style: ElevatedButton.styleFrom(
-                    backgroundColor: Colors.red,
+                    backgroundColor: colorScheme.error,
-                    foregroundColor: Theme.of(context).colorScheme.onPrimary,
+                    foregroundColor: colorScheme.onError,
                   ),
                   onPressed: () {
                     Navigator.of(context).pop();