style: update card background colors in templates

frontend/src/app/feature/game/blackjack/components/dealer-hand/dealer-hand.component.ts

@@ -10,7 +10,7 @@ import { Card } from '../../models/card.model';
   template: `
     <div class="space-y-4">
       <h3 class="section-heading text-2xl mb-4">Croupier's Karten</h3>
-      <div class="card p-6 !bg-red-500">
+      <div class="card p-6 !bg-accent-red">
         <div class="flex justify-center gap-4 min-h-[160px] p-4 border-2 border-red-400 rounded-lg">
           <app-playing-card
             *ngFor="let card of cards"