feat: zufällige Hintergrundfarbe aus 8 Pastelltönen beim Start

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

index.html

@@ -165,6 +165,10 @@
     </div>
   </div>
 
+  <script>
+    const _bg = ['#F5DFE3','#F5E6DF','#F5F2DF','#E3F5DF','#DFF5F0','#E9DFF5','#F5DFF0','#DFE9F5'];
+    document.body.style.background = _bg[Math.floor(Math.random() * _bg.length)];
+  </script>
   <script src="https://cdnjs.cloudflare.com/ajax/libs/lottie-web/5.12.2/lottie.min.js"></script>
   <script type="module" src="js/app.js"></script>
   <script>