* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
       
        :root {
            --primary: #3498db;
            --secondary: #2c3e50;
            --accent: #e74c3c;
            --light: #ecf0f1;
            --dark: #2c3e50;
            --success: #27ae60;
            --text: #333;
            --text-light: #777;
            --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
            --transition: all 0.3s ease;
        }
       
        body {
            background-color: #f5f7fa;
            color: var(--text);
            line-height: 1.6;
        }
       
        .container {
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 15px;
        }
       
        /* 头部样式 */
        header {
            background: linear-gradient(135deg, var(--secondary) 0%, var(--primary) 100%);
            color: white;
            padding: 1rem 0;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 100;
        }
       
        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
       
        .logo {
            font-size: 1.8rem;
            font-weight: bold;
            display: flex;
            align-items: center;
        }
       
        .logo i {
            margin-right: 10px;
            color: var(--accent);
        }
       
        /* 导航菜单 */
        nav ul {
            display: flex;
            list-style: none;
        }
       
        nav ul li {
            margin-left: 1.5rem;
            position: relative;
        }
       
        nav ul li a {
            color: white;
            text-decoration: none;
            font-weight: 500;
            transition: var(--transition);
            padding: 0.5rem 0.8rem;
            border-radius: 4px;
        }
       
        nav ul li a:hover {
            color: var(--accent);
            background: rgba(255, 255, 255, 0.1);
        }
       
        nav ul li a.active {
            background: var(--accent);
            color: white;
        }
       
        /* 移动端菜单按钮 */
        .menu-toggle {
            display: none;
            font-size: 1.5rem;
            cursor: pointer;
            color: white;
        }
       
        /* 主内容区 */
        main {
            padding: 2rem 0;
            min-height: calc(100vh - 180px);
        }
       
        .page-header {
            text-align: center;
            margin-bottom: 2rem;
        }
       
        .page-header h1 {
            font-size: 2.5rem;
            color: var(--secondary);
            margin-bottom: 0.5rem;
        }
       
        .page-header p {
            color: var(--text-light);
            font-size: 1.2rem;
        }
       
        /* 分类网格 */
        .category-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 25px;
            margin-top: 2rem;
        }
       
        .category-card {
            background: white;
            border-radius: 10px;
            overflow: hidden;
            box-shadow: var(--shadow);
            transition: var(--transition);
            text-align: center;
        }
       
        .category-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
        }
       
        .category-card img {
            width: 100%;
            height: 135px;
            object-fit: cover;
            border-bottom: 3px solid var(--primary);
        }
       
        .category-content {
            padding: 1.5rem;
        }
       
        .category-content h3 {
            margin-bottom: 0.5rem;
            color: var(--secondary);
            font-size: 1.4rem;
        }
       
        .category-content p {
            color: var(--text-light);
            margin-bottom: 1.5rem;
        }
       
        .btn {
            display: inline-block;
            background: var(--primary);
            color: white;
            padding: 0.7rem 1.5rem;
            border-radius: 50px;
            text-decoration: none;
            font-weight: 500;
            transition: var(--transition);
            border: 2px solid var(--primary);
        }
       
        .btn:hover {
            background: transparent;
            color: var(--primary);
        }
       
        /* 产品表格 */
        .table-container {
            width: 100%;
            overflow-x: auto;
            margin-top: 2rem;
            background: white;
            box-shadow: var(--shadow);
            border-radius: 10px;
            padding: 1rem;
        }
       
        .product-table {
            width: 100%;
            border-collapse: collapse;
            table-layout: fixed;
        }
       
        .product-table th,
        .product-table td {
            padding: 1rem;
            text-align: center;
            border-bottom: 1px solid #e0e0e0;
            word-wrap: break-word;
            vertical-align: middle;
        }
       
        .product-table th {
            background: var(--light);
            font-weight: 600;
            color: var(--secondary);
            position: sticky;
            top: 0;
        }
       
        .product-table tr:last-child td {
            border-bottom: none;
        }
       
        .product-table img {
            object-fit: cover;
            border-radius: 8px;
            border: 2px solid var(--light);
            transition: var(--transition);
        }
       
        /* 固定列宽比例 */
        .col-name {
            width: 40%;
        }
       
        .col-image {
            width: 35%;
        }
       
        .col-download {
            width: 25%;
        }
       
        /* 表格内容样式 */
        .product-name {
            font-weight: 600;
            color: var(--secondary);
            line-height: 1.4;
        }
       
        .download-link {
            display: inline-block;
            background: var(--success);
            color: white;
            padding: 0.6rem 1rem;
            border-radius: 4px;
            text-decoration: none;
            font-weight: 500;
            transition: var(--transition);
            text-align: center;
            font-size: 0.9rem;
        }
       
        .download-link:hover {
            background: #219653;
            transform: translateY(-2px);
        }
       
        .download-link i {
            margin-right: 5px;
        }
       
        /* 返回按钮 */
        .back-btn {
            display: inline-flex;
            align-items: center;
            margin-bottom: 1.5rem;
            color: var(--primary);
            text-decoration: none;
            font-weight: 500;
            transition: var(--transition);
        }
       
        .back-btn:hover {
            color: var(--accent);
        }
       
        .back-btn i {
            margin-right: 5px;
        }
       
        /* 页脚 */
        footer {
            background: var(--secondary);
            color: white;
            text-align: center;
            padding: 2rem 0;
            margin-top: 3rem;
        }
       
        .footer-content {
            display: flex;
            flex-direction: column;
            align-items: center;
        }
       
        .footer-logo {
            font-size: 1.8rem;
            font-weight: bold;
            margin-bottom: 1rem;
        }
       
        .footer-links {
            display: flex;
            gap: 20px;
            margin-bottom: 1.5rem;
        }
       
        .footer-links a {
            color: white;
            text-decoration: none;
            transition: var(--transition);
        }
       
        .footer-links a:hover {
            color: var(--accent);
        }
       
        .copyright {
            color: #aaa;
            font-size: 0.9rem;
        }
       
        /* 响应式设计 */
        @media (max-width: 992px) {
            .category-grid {
                grid-template-columns: repeat(2, 1fr);
            }
           
            /* 调整表格列宽比例 */
            .col-name {
                width: 40%;
            }
           
            .col-image {
                width: 35%;
            }
           
            .col-download {
                width: 25%;
            }
        }
       
        @media (max-width: 768px) {
            .menu-toggle {
                display: block;
            }
           
            nav {
                position: absolute;
                top: 70px;
                left: 0;
                width: 100%;
                background: var(--secondary);
                display: none;
                padding: 1rem 0;
                box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
            }
           
            nav.active {
                display: block;
            }
           
            nav ul {
                flex-direction: column;
            }
           
            nav ul li {
                margin: 0;
                text-align: center;
                padding: 0.5rem 0;
            }
           
            .category-grid {
                grid-template-columns: 1fr;
            }
           
            /* 移动端表格样式调整 */
            .product-table {
                font-size: 0.9rem;
            }
           
            .product-table th,
            .product-table td {
                padding: 0.7rem 0.5rem;
            }
           
            .product-table img {
                width: 70px;
                height: 70px;
            }
           
            .download-link {
                padding: 0.5rem 0.7rem;
                font-size: 0.8rem;
            }
        }
       
        @media (max-width: 576px) {
            .page-header h1 {
                font-size: 2rem;
            }
           
            /* 移动端表格进一步调整 */
            .product-table {
                font-size: 0.85rem;
            }
           
            .product-table th,
            .product-table td {
                padding: 0.6rem 0.4rem;
            }
           
            .product-table img {
                width: 60px;
                height: 60px;
            }
           
            .download-link {
                padding: 0.4rem 0.6rem;
                font-size: 0.75rem;
            }
           
            /* 确保列宽比例 */
            .col-name {
                width: 35%;
            }
           
            .col-image {
                width: 25%;
            }
           
            .col-download {
                width: 40%;
            }
        }