diff --git a/frontend/src/components/ai/ChatWindow.tsx b/frontend/src/components/ai/ChatWindow.tsx
index 726020d..56a0444 100644
--- a/frontend/src/components/ai/ChatWindow.tsx
+++ b/frontend/src/components/ai/ChatWindow.tsx
@@ -160,7 +160,7 @@ export function ChatWindow({ sessionId, agentId, className, compact }: ChatWindo
             <div className={clsx('text-xs font-medium mb-1', msg.role === 'user' ? 'text-primary-600' : 'text-secondary-400')}>
               {msg.role === 'user' ? 'Du' : 'KI'}
             </div>
-            <div className="text-sm text-secondary-900">
+            <div className={clsx('rounded-lg px-4 py-2 text-sm', msg.role === 'user' ? 'bg-primary-50 border border-primary-100' : '')}>
               <MessageContent content={msg.content} role={msg.role} />
               {msg.tool_calls && msg.tool_calls.length > 0 && (
                 <div className="mt-2 text-xs text-secondary-400 border-l-2 border-secondary-200 pl-2">