design: Minor color changes

lib/config/themes.dart

@@ -135,7 +135,7 @@ abstract class FluffyThemes {
               primary: FluffyThemes.lighten(AppConfig.chatColor, 0.33),
               secondary: FluffyThemes.lighten(AppConfig.chatColor, 0.33),
               secondaryVariant: AppConfig.secondaryColor,
-              surface: FluffyThemes.darken(AppConfig.chatColor, 0.4),
+              surface: FluffyThemes.darken(AppConfig.chatColor, 0.35),
             ),
         secondaryHeaderColor: Colors.blueGrey.shade900,
         textTheme: Typography.material2018().white.merge(fallbackTextTheme),

lib/pages/chat/chat_view.dart

@@ -331,7 +331,7 @@ class ChatView extends StatelessWidget {
                             .secondaryHeaderColor
                             .withAlpha(100),
                         clipBehavior: Clip.hardEdge,
-                        color: Theme.of(context).backgroundColor,
+                        color: Theme.of(context).appBarTheme.backgroundColor,
                         child: SafeArea(
                           child: Column(
                             mainAxisSize: MainAxisSize.min,