style(ui): 更新视频背景样式和页面布局调整

- 将视频背景改为图片背景
- 调整ChoosePage页面的文本大小
- 在PosterPage底部添加说明文字

 <!--
  * @Date: 2025-12-26 14:15:46
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-12-31 12:52:38
+ * @LastEditTime: 2025-12-31 16:47:19
  * @FilePath: /mlaj/src/components/ui/VideoBackground.vue
  * @Description: 文件描述
 -->
@@ -122,6 +122,6 @@ const enable_image_fallback = () => {
     right: -1px;
     bottom: -1px;
     left: -1px;
-    background: #000;
+    background-image: url(https://cdn.ipadbiz.cn/mlaj/recall/img/bg01@2x.png?imageMogr2/thumbnail/400x/strip/quality/50);
 }
 </style>

 <!--
  * @Date: 2025-12-30 13:58:55
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-12-31 13:11:28
+ * @LastEditTime: 2025-12-31 14:43:54
  * @FilePath: /mlaj/src/views/recall/ChoosePage.vue
  * @Description: 文件描述
 -->
@@ -17,7 +17,7 @@
     <!-- 容器靠页面底部对齐 -->
     <div class="flex flex-col items-center h-full w-full px-6 pt-16 pb-8 relative mt-auto">
       <div class="text-white text-center space-y-1 tracking-wider text-shadow-md mb-3">
-        <p class="text-base">{{ viewOther.text }}</p>
+        <p class="text-lg">{{ viewOther.text }}</p>
       </div>
       <!-- Bottom Section -->
       <div class="mt-auto w-full flex flex-col items-center text-center animate-fade-in-up delay-200">

 <!--
  * @Date: 2025-12-23 15:50:59
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-12-26 16:06:36
+ * @LastEditTime: 2025-12-31 17:04:10
  * @FilePath: /mlaj/src/views/recall/PosterPage.vue
  * @Description: 分享海报页面
 -->
@@ -23,7 +23,8 @@
     </div>
 
     <!-- Buttons (Fixed at Bottom) -->
-    <div class="fixed bottom-0 left-0 right-0 px-8 py-3 flex gap-4 z-50 max-w-md mx-auto w-full">
+    <div class="fixed bottom-0 left-0 right-0 px-8 py-3 z-50 max-w-md mx-auto w-full">
+      <div class="flex gap-4">
         <van-uploader :after-read="afterRead" accept="image/*" class="flex-1 w-full" :show-upload="false">
           <template #default>
             <van-button block color="#0052D9" plain
@@ -33,6 +34,10 @@
           </template>
         </van-uploader>
       </div>
+      <div class="mt-2 text-[12px] leading-[16px] text-white/80 text-center">
+        上传您参加活动时的照片，制作独有海报
+      </div>
+    </div>
   </div>
 </template>