src/pages/ChangeCalculatorPage.tsx

@@ -34,7 +34,8 @@ const ChangeCalculatorPage: React.FC = () => {
   useEffect(() => {
     const total = moneyItems.reduce((sum, item) => sum + item.value * item.count, 0);
     setCustomerTotal(total);
-    setChangeAmount(Math.max(0, total - cartTotal));
+    // Allow negative values when customer hasn't paid enough
+    setChangeAmount(total - cartTotal);
   }, [moneyItems, cartTotal]);
 
   const handleDenominationClick = (index: number) => {
@@ -90,7 +91,14 @@ const ChangeCalculatorPage: React.FC = () => {
           </div>
           <div className="total-item highlight">
             <span>Restgeld:</span>
-            <span>{changeAmount.toFixed(2)} €</span>
+            <span 
+              style={{ 
+                color: changeAmount < 0 ? '#ff0000' : 'inherit',
+                fontWeight: changeAmount < 0 ? 'bold' : 'inherit'
+              }}
+            >
+              {changeAmount.toFixed(2)} €
+            </span>
           </div>
         </div>
 

src/pages/HomePage.tsx

@@ -39,8 +39,7 @@ const HomePage: React.FC = () => {
             </button>
           </div>
           
-          <h2 className="section-title">{activeTab === 'food' ? 'Essen' : 'Getränke'}</h2>
-          <ProductList 
+          <ProductList
             products={productsData[activeTab]} 
             category={activeTab} 
           />