style(UploadMedia): 调整上传页面按钮和提示文字样式

@@ -12,7 +12,7 @@
         <view class="text-gray-400 mb-4">
           <Photograph size="48" />
         </view>
-        <view class="text-center text-gray-600 mb-2">选择图片或视频</view>
+        <view class="text-center text-gray-600 mb-2 text-sm">选择图片或视频</view>
         <view class="text-center text-gray-400 text-sm">
           支持图片格式（jpg、png）最大10MB或60秒内视频
         </view>
@@ -75,14 +75,14 @@
       <view class="flex gap-3">
         <view
           @tap="chooseMedia"
-          class="flex-1 bg-gray-100 text-gray-700 py-3 rounded-lg text-center"
+          class="flex-1 bg-gray-100 text-gray-700 py-3 rounded-lg text-center text-sm"
         >
           {{ uploadedFile ? '重新选择' : '选择文件' }}
         </view>
         <view
           v-if="uploadedFile"
           @tap="saveMedia"
-          class="flex-1 bg-blue-500 text-white py-3 rounded-lg text-center"
+          class="flex-1 bg-blue-500 text-white py-3 rounded-lg text-center text-sm"
         >
           提交
         </view>