feat: 新增'分类展开/收起'按钮

assets/style.css

@@ -626,6 +626,42 @@ body .content.expanded {
     z-index: 10;
 }
 
+/* 分类切换按钮 */
+.category-toggle {
+    position: fixed;
+    bottom: 5rem;
+    right: 2rem;
+    width: 40px;
+    height: 40px;
+    border-radius: 10px;
+    background: linear-gradient(145deg, var(--site-card-bg-gradient-1), var(--site-card-bg-gradient-2));
+    color: var(--text-bright);
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    cursor: pointer;
+    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
+    z-index: 100;
+    box-shadow: 0 4px 16px var(--shadow-color);
+    border: 1px solid var(--border-color);
+}
+
+.category-toggle:hover {
+    transform: translateY(-2px);
+    background: linear-gradient(145deg, var(--secondary-bg), var(--site-card-bg-gradient-1));
+    box-shadow: 0 6px 20px var(--shadow-color);
+    color: var(--accent-color);
+}
+
+.category-toggle:active {
+    transform: translateY(0);
+    box-shadow: 0 2px 8px var(--shadow-color);
+}
+
+.category-toggle i {
+    font-size: 18px;
+}
+
 /* 搜索框 */
 .search-box {
     position: relative;
@@ -1730,6 +1766,12 @@ body .content.expanded {
         animation: glow 3s ease-in-out infinite alternate;
     }
 
+    /* 移动端分类切换按钮 */
+    .category-toggle {
+        bottom: 4rem;
+        right: 1rem;
+    }
+
     /* 分类样式优化 */
     .category {
         margin: 0 0.15rem 1.5rem 0.15rem;
@@ -1792,6 +1834,7 @@ body .content.expanded {
 }
 
 @media (max-width: 480px) {
+
     .welcome-section {
         padding: 0 1rem;
         margin-bottom: 2rem;