* {
             margin: 0;
             padding: 0;
             box-sizing: border-box;
             font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
         }
         body {
             background-color: #f5f5f5;
         }
         /* 顶部导航栏 */
         .header {
             background-color: #d92222;
             color: white;
             padding: 16px 20px;
             display: flex;
             align-items: center;
             gap: 12px;
             box-shadow: 0 2px 4px rgba(0,0,0,0.1);
         }
         .header .logo-icon {
             font-size: 32px;
         }
         .header .title {
             font-size: 34px;
             font-weight: bold;
         }
         /* 公告栏 */
         .notice-bar {
             background-color: #333333;
             color: white;
             margin: 12px 16px;
             padding: 12px 16px;
             border-radius: 12px;
             display: flex;
             align-items: center;
             justify-content: space-between;
         }
         .notice-bar .notice-text {
             font-size: 16px;
         }
         .notice-bar .close-btn {
             background-color: #666;
             border: none;
             color: white;
             width: 32px;
             height: 32px;
             border-radius: 50%;
             font-size: 18px;
             cursor: pointer;
             display: flex;
             align-items: center;
             justify-content: center;
         }
         /* 下载区域 */
         .download-section {
             padding: 24px 16px;
         }
         .download-title {
             font-size: 26px;
             font-weight: bold;
             margin-bottom: 24px;
             display: flex;
             align-items: center;
             gap: 8px;
         }
         .download-title::before {
             content: "";
             display: inline-block;
             width: 6px;
             height: 28px;
             background-color: #d92222;
         }
         .download-container {
             display: grid;
             grid-template-columns: 1fr 1fr;
             gap: 20px;
         }
         .download-card {
             background-color: white;
             border-radius: 16px;
             overflow: hidden;
             box-shadow: 0 2px 8px rgba(0,0,0,0.08);
             display: flex;
             flex-direction: column;
             align-items: center;
             padding: 24px 16px;
             text-align: center;
         }
         .download-card .icon {
             font-size: 64px;
             margin-bottom: 16px;
         }
         .download-card.android .icon {
             color: #3ddc84;
         }
         .download-card.windows .icon {
             color: #0078d4;
         }
         .download-card .platform-name {
             font-size: 20px;
             font-weight: bold;
             margin-bottom: 8px;
         }
         .download-card .desc {
             font-size: 14px;
             color: #666;
             margin-bottom: 20px;
             line-height: 1.5;
         }
         .download-btn {
             background-color: #d92222;
             color: white;
             border: none;
             padding: 12px 32px;
             border-radius: 24px;
             font-size: 16px;
             font-weight: bold;
             cursor: pointer;
             transition: background-color 0.2s ease;
         }
         .download-btn:hover {
             background-color: #b81b1b;
         }
         /* 底部导航 */
         .bottom-nav {
             position: fixed;
             bottom: 0;
             left: 0;
             right: 0;
             background-color: white;
             display: flex;
             justify-content: space-around;
             padding: 12px 0;
             border-top: 1px solid #eee;
         }
         .nav-item {
             display: flex;
             flex-direction: column;
             align-items: center;
             color: #888;
             text-decoration: none;
             font-size: 14px;
         }
         .nav-item.active {
             color: #d92222;
         }
         .nav-item .nav-icon {
             font-size: 28px;
             margin-bottom: 4px;
         }
         /* 适配移动端 */
         @media (max-width: 600px) {
             .download-container {
                 grid-template-columns: 1fr;
             }
         }