style(StudyPage): 调整按钮的样式以提升视觉一致性

将按钮的内边距和字体大小调整为更小的尺寸，以保持页面元素的视觉一致性

@@ -31,12 +31,12 @@
             <van-tab title="学习记录" name="record">
                 <div class="p-4">
                     <div class="flex space-x-4 mb-4">
-                        <button class="rounded-full px-6 py-2 text-sm transition-colors"
+                        <button class="rounded-full px-4 py-1 text-xs transition-colors"
                             :class="courseType === 'column' ? 'bg-green-500 text-white' : 'bg-gray-100 text-gray-600'"
                             @click="courseType = 'column'">
                             专栏
                         </button>
-                        <button class="rounded-full px-6 py-2 text-sm transition-colors"
+                        <button class="rounded-full px-4 py-1 text-xs transition-colors"
                             :class="courseType === 'single' ? 'bg-green-500 text-white' : 'bg-gray-100 text-gray-600'"
                             @click="courseType = 'single'">
                             单课