:root {
      --bg: #fcfcfc;
      --text: #2c3e50;
      --card-bg: #ffffff;
      --border: #e0e0e0;
      --primary: #3498db;
      --card-shadow: 0 4px 6px rgba(0,0,0,0.05);
      --card-hover-shadow: 0 6px 12px rgba(0,0,0,0.1);
    }
    [data-theme="dark"] {
      --bg: #1a1a1a;
      --text: #e0e0e0;
      --card-bg: #2d2d2d;
      --border: #404040;
      --primary: #2980b9;
      --card-shadow: 0 4px 6px rgba(0,0,0,0.2);
      --card-hover-shadow: 0 6px 12px rgba(0,0,0,0.3);
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    img {
    max-width: 100%;
    height: auto;
    display: block; /* 去除图片底部间隙 */
    }
    html {
        scroll-padding-top: 3.5rem;
    }
    body {
      background: var(--bg);
      color: var(--text);
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      line-height: 1.6;
      transition: background 0.3s, color 0.3s;
      padding: 3.5rem 0 0 0;
    }
    /* 统一广告位样式 */
    .ad-box {
      display: flex;
      justify-content: center;
      align-items: center;
      background: var(--card-bg);
      border: 1px solid var(--border);
      border-radius: 5px;
      max-width: 100%;
      box-shadow: var(--card-shadow);
    }
    .ad-box img {
      max-width: 100%;
      height: auto;
      border-radius: 5px;
    }
        /* 侧边广告位 */
    .side-ad {
      margin: 0.1rem;
      padding: 0.1rem;
      border: 1px dashed var(--border);
      text-align: center;
      border-radius: 5px;
      background: rgba(0,0,0,0.03);
    }
    .side-ad img {
      max-width: 100%;
      height: auto;
      border-radius: 5px;
    }
    /* 导航栏 */
    .nav {
      display: flex;
      align-items: center;
      padding:0 1rem;
      border-bottom: 1px solid var(--border);
      background: var(--card-bg);
      position: fixed; /* 关键属性：固定定位,导航栏位于最前方 */
      top: 0;
      left: 0;
      width: 100%; 
      z-index: 1000;
      box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    }
    .menu-btn {
      background: none;
      border: none;
      font-size: 1.5rem;
      color: var(--text);
      cursor: pointer;
      padding: 0.5rem;
      display: none;
    }
    .nav h1 {
      flex-grow: 1;
      text-align: center;
      font-size: 1.2rem;
      color: var(--primary);
      letter-spacing: 1px;
    }
    /* 主题切换按钮样式 */
    #themeToggle {
      background: none;
      border: none;
      cursor: pointer;
      padding: 0.5rem;
      transition: transform 0.3s;
      width: 40px;
      height: 40px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    #themeToggle:hover {
      transform: rotate(15deg);
    }
    #themeToggle svg {
      width: 24px;
      height: 24px;
      fill: var(--text);
      transition: fill 0.3s;
    }
    .theme-icon {
      width: 24px;
      height: 24px;
    }
    /* 侧边菜单 */
    .side-menu {
      position: fixed;
      left: 0;
      top: 1rem;
      bottom: 0;
      width: 250px;
      background: var(--card-bg);
      border-right: 1px solid var(--border);
      transition: transform 0.3s ease;
      padding: 2rem 1rem;
      overflow-y: auto;
      z-index: 200;
      transform: translateX(-100%);
      box-shadow: 2px 0 10px rgba(0,0,0,0.1);
    }
    .side-menu.active {
      transform: translateX(0);
    }
    .category-list {
      list-style: none;
      padding-left: 15px;
      margin-bottom: 2rem;
    }
    /*手机端左边分类列表*/
    .category-item {
      margin: 0.8rem 0;
    }
    .category-link {
      font-weight: 600;
      color: var(--text);
      text-decoration: none;
      padding: 0.8rem;
      display: block;
      border-radius: 6px;
      transition: background 0.2s, transform 0.2s;
    }
    .category-link:hover {
      background: rgba(0,0,0,0.05);
      transform: translateX(5px);
    }
    /* 遮罩层 */
    .overlay {
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      background: rgba(0,0,0,0.3);
      z-index: 150;
      display: none;
      opacity: 0;
      transition: opacity 0.3s;
    }
    .overlay.active {
      display: block;
      opacity: 1;
    }
    /* 主内容区域 */
    main {
      max-width: 1200px;
      margin: 0 auto;
      padding: 1==rem;
      transition: margin 0.3s;
    }
    /*每个大分类*/
    .section {
      margin-bottom: 0.5rem;
      background: var(--card-bg);
      border-radius: 12px;
      overflow: hidden;
      box-shadow: var(--card-shadow);
    }
    /*分类的标题*/
    .section-title {
      font-size: 1rem;
      padding: 1rem 1.5rem;
      background: rgba(52, 152, 219, 0.1);
      color: var(--primary);
      display: flex;
      align-items: center;
    }
    .section-title::before {
      content: "•";
      margin-right: 8px;
      font-size: 2rem;
    }
    /*每个格子*/
    .card-grid {
      display: grid;
      gap: 1.2rem;
      grid-template-columns: repeat(4,1fr);
      padding: 0.2rem;
    }
    /*每个卡片的具体设置*/
    .card {
      background: var(--card-bg);
      padding: 1.5rem;
      border-radius: 10px;
      border: 1px solid var(--border);
      transition: all 0.2s;
      text-decoration: none;
      color: var(--text);
      display: flex;
      flex-direction: column;
      box-shadow: var(--card-shadow);
      position: relative;
      overflow: hidden;
    }
    .card:hover {
      transform: translateY(-5px);
      box-shadow: var(--card-hover-shadow);
    }
    .card:hover::after {
      content: "";
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 4px;
      background: var(--primary);
    }
    .card-title {
      font-weight: 600;
      margin-bottom: 0.5rem;
      font-size: 1rem;
      display: flex;
      align-items: center;
    }
    .card-title::before {
      content: "❄";
      margin-right: 8px;
      color: var(--primary);
      font-size: 1rem;
    }
    .card-desc {
      font-size: 0.6em;
      color: #7f8c8d;
      margin-top: 0.5rem;
      margin-left: 0.5rem;
      line-height: 1.5;
    }

    /* 页脚 */
    footer {
      text-align: center;
      padding: 0.5rem;
      background: var(--card-bg);
      border-top: 1px solid var(--border);
      font-size: 0.9rem;
      color: #7f8c8d;
    }
    /* 加载指示器 */
    .loader {
      display: flex;
      justify-content: center;
      align-items: center;
      min-height: 300px;
      font-size: 1.2rem;
      color: var(--text);
    }
    .loader::after {
      content: "❄";
      display: inline-block;
      margin-left: 10px;
      animation: spin 1s linear infinite;
    }
    
    @keyframes spin {
      0% { transform: rotate(0deg); }
      100% { transform: rotate(360deg); }
    }   
    @media (max-width: 768px) {
      .menu-btn {
        display: block;
      }
      .side-menu {
        width: 60%;
        padding-top: 3rem;
      }
      main {
        padding: 0.5rem;
      }
      .card-grid {
        grid-template-columns: repeat(2,1fr);
        gap: 0.8rem;
        padding: 1rem;
      }
      .card {
        padding: 1rem;
      }
      .section-title {
        padding: 1rem;
        font-size: 1.3rem;
      }
    }
    /*友链*/
    .footer-links {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      align-items: center;
      gap: 1px;
      padding: 2px 0;
      border-top: 1px solid rgba(255, 255, 255, 0.1);
    }
    
    .footer-links a,p {
      color: inherit;
      text-decoration: none;
      /*font-size: 1rem;*/
      padding: 3px 10px;
      border-radius: 4px;
      transition: all 0.3s ease;
    }
    
    .footer-links a:hover {
      color: var(--text);
      background: rgba(255, 255, 255, 0.1);
    }