style(StudyCoursePage): 移除图片的固定宽高比限制

@@ -6,7 +6,7 @@
 <AppLayout :has-title="false">
     <div class="study-course-page bg-gradient-to-b from-green-50/70 to-white/90 min-h-screen">
         <div v-if="course" class="bg-white">
-            <van-image class="w-full aspect-video object-cover" :src="course?.cover || 'https://cdn.ipadbiz.cn/mlaj/images/default_block.png'" :alt="course?.title" />
+            <van-image class="w-full object-cover" :src="course?.cover || 'https://cdn.ipadbiz.cn/mlaj/images/default_block.png'" :alt="course?.title" />
             <div class="p-4">
                 <div class="flex items-start justify-between gap-3 mb-2">
                     <h1 class="text-black text-xl font-bold flex-1 min-w-0">{{ course?.title }}</h1>