style(PdfViewer): 移除zoom-btn的悬停样式以简化UI

 <!--
  * @Date: 2025-01-21
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-10-22 13:36:27
+ * @LastEditTime: 2025-10-22 13:42:16
  * @FilePath: /mlaj/src/components/ui/PdfViewer.vue
  * @Description: PDF预览组件 - 使用pdf-vue3库
 -->
@@ -769,13 +769,13 @@ const applyPinchZoom = (newZoom, centerX, centerY, container) => {
     box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
 }
 
-.zoom-btn:hover {
+/* .zoom-btn:hover {
     background: #4caf50;
     color: #fff;
     border-color: #4caf50;
     transform: scale(1.1);
     box-shadow: 0 4px 12px rgba(25, 137, 250, 0.3);
-}
+} */
 
 .zoom-btn:active {
     transform: scale(0.95);