:root {
            --primary-color: #1a3a6d;
            --secondary-color: #2e5aa7;
            --light-bg: #f5f7fa;
            --card-bg: #ffffff;
            --text-dark: #333333;
            --text-medium: #555555;
            --text-light: #777777;
            --border-color: #e1e5eb;
            --hover-color: #f0f5ff;
            --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            --radius: 8px;
            --transition: all 0.3s ease;
        }
        

        .container {
            max-width: 1400px;
            margin: 0 auto;
            padding:50px 0;
            box-sizing: border-box;
        }
        

        /* 内容区域 */
        .content-area {
            display: flex;
            gap: 30px;
            padding:0 0 50px 0;
        }
        
        /* 左侧导航 - 简洁版 */
        .category-nav {
            flex: 0 0 220px;
            background: var(--card-bg);
            border-radius: var(--radius);
            box-shadow: var(--shadow);
            height: fit-content;
            position: sticky;
            top: 30px;
        }
        
        .category-nav h2 {
            color: var(--primary-color);
            padding: 20px;
            border-bottom: 1px solid var(--border-color);
            margin-bottom: 0;
            font-size: 1.3rem;
            position: sticky;
            top: 0;
            background: var(--card-bg);
            z-index: 2;
        }
        
        .category-list {
            list-style: none;
            padding: 15px 0;
        }
        
        .category-item {
            padding: 14px 24px;
            transition: var(--transition);
            cursor: pointer;
            display: flex;
            align-items: center;
            position: relative;
            font-size: 1.05rem;
        }
        
        .category-item:hover {
            background: var(--hover-color);
        }
        
        .category-item.active {
            color: var(--primary-color);
            font-weight: 600;
        }
        
        .category-item.active::before {
            content: '';
            position: absolute;
            left: 0;
            top: 0;
            height: 100%;
            width: 4px;
            background: var(--primary-color);
            border-radius: 0 4px 4px 0;
        }
        
        /* 产品网格 */
        .products-grid {
            flex: 1;
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 25px;
        }
        
        .product-card {
            background: var(--card-bg);
            border-radius: var(--radius);
            overflow: hidden;
            box-shadow: var(--shadow);
            transition: var(--transition);
            display: flex;
            flex-direction: column;
            height: 100%;
        }
        
        .product-card:hover {
            transform: translateY(-8px);
            box-shadow: 0 12px 20px rgba(0, 0, 0, 0.12);
        }
        
        /* 产品图片 - 满框无边距 */
        .product-image {
            height: 300px;
            display: flex;
            align-items: center;
            justify-content: center;
            overflow: hidden;
            background: linear-gradient(135deg, #f0f5ff, #e6eeff);
        }
        
        .product-image img {
            width: auto;
            height: 100%;
            object-fit: cover;
            transition: transform 0.4s ease;
        }
        
        .product-card:hover .product-image img {
            transform: scale(1.05);
        }
        
        .product-info {
            padding: 20px;
            flex-grow: 1;
        }
        
        .product-name {
            color: var(--primary-color);
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: 12px;
            line-height: 1.3;
        }
        
        .product-brand {
            color: var(--secondary-color);
            font-weight: 600;
            margin-bottom: 5px;
            display: block;
        }
        
        .product-model {
            color: var(--text-light);
            font-size: 0.95rem;
            margin-bottom: 15px;
            padding: 6px 0;
            display: block;
            border-bottom: 1px dashed var(--border-color);
        }
        
        .product-description {
            color: var(--text-medium);
            font-size: 0.95rem;
            line-height: 1.7;
        }
        
        .product-actions {
            padding: 0 20px 20px;
        }
        
        .btn-details {
            display: inline-flex;
            align-items: center;
            color: #1a3a6d;
            font-weight: 600;
            text-decoration: none;
            transition: all 0.3s ease;
            margin-top: 10px;
        }
        
        .btn-details i {
            margin-left: 8px;
            transition: transform 0.3s ease;
            font-size: 0.9rem;
        }
        
        .btn-details:hover {
            color: #3182ce;
        }
        
        .btn-details:hover i {
            transform: translateX(5px);
        }
        
        /* 响应式设计优化 */
        @media (max-width: 1200px) {
            .products-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .content-area {
                gap: 20px;
            }
            
            .category-nav {
                flex: 0 0 200px;
            }
        }
        
        @media (max-width: 900px) {
            .content-area {
                flex-direction: column;
            }
            
            .category-nav {
                width: 100%;
                position: relative;
                top: 0;
            }
            
            .category-list {
                display: grid;
                grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
                gap: 5px;
                padding: 10px;
            }
            
            .category-item {
                padding: 12px 15px;
                border-radius: 6px;
                font-size: 1rem;
            }
            
            .category-item.active::before {
                width: 100%;
                height: 4px;
                top: auto;
                bottom: 0;
                border-radius: 4px 4px 0 0;
            }
            
            .page-header h1 {
                font-size: 2.2rem;
            }
        }
        
        @media (max-width: 768px) {
            .products-grid {
                grid-template-columns: 1fr;
                gap: 20px;
            }
            
            .page-header {
                padding: 10px 0 30px;
            }
            
            .page-header h1 {
                font-size: 2rem;
            }
            
            .page-header p {
                font-size: 1rem;
            }
            
            .product-image {
                height: 266px;
            }
        }
        
        @media (max-width: 480px) {
            body {
                padding: 0 0;
            }
            
            .container{
                padding: 15px 15px;
            }
            .category-list {
                grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
            }
            
            .category-item {
                padding: 10px 12px;
                font-size: 0.95rem;
            }
            
            .product-info {
                padding: 15px;
            }
            
            .product-name {
                font-size: 1.2rem;
            }
        }
        
        /* 小屏幕下的导航切换 */
        .mobile-category-toggle {
            display: none;
            background: var(--primary-color);
            color: white;
            padding: 12px 20px;
            border-radius: var(--radius);
            margin-bottom: 20px;
            cursor: pointer;
            font-weight: 600;
            justify-content: space-between;
            align-items: center;
        }
        
        @media (max-width: 900px) {
            .mobile-category-toggle {
                display: flex;
            }
            
            .category-nav {
                display: none;
            }
            
            .category-nav.active {
                display: block;
            }
        }
        
        /* 页脚 */
        footer {
            margin-top: 50px;
            text-align: center;
            color: var(--text-light);
            padding: 20px;
            font-size: 0.9rem;
        }
        
        /* 滚动条美化 */
        .category-nav::-webkit-scrollbar {
            width: 6px;
        }
        
        .category-nav::-webkit-scrollbar-track {
            background: #f1f1f1;
            border-radius: 10px;
        }
        
        .category-nav::-webkit-scrollbar-thumb {
            background: #c1c9e0;
            border-radius: 10px;
        }
        
        .category-nav::-webkit-scrollbar-thumb:hover {
            background: #a1abcc;
        }