优化底部操作栏样式，调整布局和背景色，并在分类编辑页面添加安全距离

Web/src/views/ClassificationSmart.vue

@@ -27,7 +27,7 @@
     </div>
 
     <!-- 底部操作按钮 -->
-    <div class="action-bar">
+    <div class="bottom-button">
       <van-button 
         type="primary" 
         :loading="classifying"
@@ -351,27 +351,6 @@ onMounted(async () => {
   font-weight: 500;
 }
 
-/* 底部操作栏 */
-.action-bar {
-  position: fixed;
-  bottom: 0;
-  left: 0;
-  right: 0;
-  display: flex;
-  gap: 12px;
-  padding: 12px;
-  background-color: var(--van-background-2, #fff);
-  box-shadow: 0 -2px 8px rgba(0, 0, 0, 0.08);
-  z-index: 100;
-}
-
-@media (prefers-color-scheme: dark) {
-  .action-bar {
-    background-color: var(--van-background-2, #2c2c2c);
-    box-shadow: 0 -2px 8px rgba(0, 0, 0, 0.3);
-  }
-}
-
 .action-btn {
   flex: 1;
   height: 44px;