style(home): 调整使用说明模块的间距和标题样式

移除顶部外边距并为标题添加上内边距，使布局更加紧凑美观

src/pages/home/index.vue

@@ -130,10 +130,10 @@
     </div>
 
     <!-- 使用说明 -->
-    <div class="p-4 mt-6" v-if="![2, 3].includes(activityInfo.status)">
+    <div class="p-4" v-if="![2, 3].includes(activityInfo.status)">
       <div class="w-full relative">
         <div class="h-full">
-          <h3 class="h-9 text-lg text-[#E8424D] font-bold flex items-center justify-center"
+          <h3 class="h-9 text-lg text-[#E8424D] font-bold flex items-center justify-center pt-4"
             style="background: url('/并集.png') no-repeat center center / cover; background-size: 100% 100%;">
             <svg class="w-5 h-5 mr-2" fill="none" stroke="currentColor" viewBox="0 0 24 24">
               <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2"