diff --git a/src/app/cart/page.tsx b/src/app/cart/page.tsx
index a18b321..dec07fb 100644
--- a/src/app/cart/page.tsx
+++ b/src/app/cart/page.tsx
@@ -12,7 +12,14 @@ export default function CartPage() {
   const removeItem = useCart((s) => s.removeItem);
   const setQuantity = useCart((s) => s.setQuantity);
   const total = useCart((s) => s.total());
-  const hasCustomDesign = items.some((item) => item.designJson.front.length > 0 || item.designJson.back.length > 0);
+  const hasCustomDesign = items.some((item) => {
+    try {
+      const design = typeof item.designJson === 'string' ? JSON.parse(item.designJson) : item.designJson;
+      return (design.front?.length ?? 0) > 0 || (design.back?.length ?? 0) > 0;
+    } catch {
+      return false;
+    }
+  });
 
   useEffect(() => setMounted(true), []);