style: 更新活动海报和奖励详情页面的样式

调整活动海报默认图片链接和奖励详情页分享按钮的样式

 <!--
  * @Date: 2022-09-19 14:11:06
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-09-19 14:15:56
+ * @LastEditTime: 2025-09-19 14:27:33
  * @FilePath: /lls_program/src/pages/ActivitiesCover/index.vue
  * @Description: 活动海报页面 - 展示活动信息并处理定位授权
 -->
@@ -146,7 +146,7 @@ import { handleSharePageAuth, addShareFlag } from '@/utils/authRedirect'
 import { THEME_COLORS } from '@/utils/config';
 
 // 默认海报图
-const defaultPoster = 'https://cdn.ipadbiz.cn/lls_prog/images/welcome_7.jpg';
+const defaultPoster = 'https://cdn.ipadbiz.cn/lls_prog/images/welcome_8.jpg';
 /**
  * 活动海报页面组件
  * 功能：展示活动信息、处理定位授权、跳转到活动页面

 <template>
     <view class="min-h-screen bg-white pb-24">
         <!-- 分享按钮 -->
-        <button id="share" data-name="shareBtn" open-type="share" style="font-size: 0.83rem; line-height: 3; padding: 0; position: absolute; right: 40rpx; top: 40rpx; z-index: 1000;color: white; width: 70rpx; height: 70rpx; border-radius: 50%; background: rgba(0, 0, 0, 0.6);">分享</button>
+        <button id="share" data-name="shareBtn" open-type="share" style="font-size: 26rpx; padding: 0; position: absolute; right: 40rpx; top: 40rpx; z-index: 1000;color: white; width: 80rpx; background: rgba(0, 0, 0, 0.6);">分享</button>
         <!-- 内容区域 -->
             <!-- Top Image -->
             <view class="w-full h-48">