style(AD): 优化广告页面样式和布局

- 调整按钮显示逻辑，增加对 hasShare 变量的判断
- 修改按钮样式和位置，使其适应不同设备和场景

src/views/AD/Index.vue

@@ -48,25 +48,16 @@ function handleButtonClick() {
     </article>
 
     <section
-      v-if="bannerInfo?.is_display_button"
-      style="
-        width: 100vw;
-        display: flex;
-        justify-content: center;
-        align-items: center;
-        position: fixed;
-        left: 0;
-        bottom: 10px;
-      "
+      v-if="bannerInfo?.is_display_button && !hasShare"
+      style="margin-top: 20px; width: 100%; position: sticky; bottom: 10px"
     >
       <!--    立即进入   -->
       <el-button
-        v-if="hasShare"
-        style="width: 95%; height: 50px; border-radius: 15px"
+        style="width: 100%; height: 50px; border-radius: 15px"
         color="#70b937"
         @click="handleButtonClick"
       >
-        <el-text style="color: white">{{ bannerInfo.button_name }}</el-text>
+        <el-text style="color: white">{{ bannerInfo?.button_name }}</el-text>
       </el-button>
     </section>
   </section>
@@ -77,7 +68,6 @@ function handleButtonClick() {
 
 .banner-container {
   padding: $gap * 2;
-  margin-bottom: $gap * 6;
   .msg-info {
     font-family: PingFangSC-Medium;
     h2 {