fix(组件样式): 修复DemoCard和VideoCard的背景透明度样式

修正了两个卡片组件中错误的背景透明度设置，将bg-transparen/0改为正确的bg-transparent，确保UI显示一致

src/components/VideoCard.tsx

@@ -158,7 +158,7 @@ export default function VideoCard({
       )}${year ? `&year=${year}` : ''}${from ? `&from=${from}` : ''}`}
     >
       <div
-        className={`group relative w-full rounded-lg bg-transparent/0 flex flex-col cursor-pointer transition-all duration-300 ease-in-out ${
+        className={`group relative w-full rounded-lg bg-transparent flex flex-col cursor-pointer transition-all duration-300 ease-in-out ${
           isDeleting ? 'opacity-0 scale-90' : ''
         }`}
       >