:root {
            --primary-color: #3498db;
            --secondary-color: #2ecc71;
            --accent-color: #e74c3c;
            --dark-color: #2c3e50;
            --light-color: #ecf0f1;
        }
        
        body {
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
            padding-top: 76px; /* 导航栏高度 */
            background-color: #f8f9fa;
        }
        
        .navbar {
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
            background-color: #2c3e50 !important;
            border-bottom: none !important;
        }
        
        .nav-link {
            padding: 0.5rem 1rem;
            transition: all 0.3s ease;
        }
        
        .nav-link:hover, .nav-link.active {
            background-color: rgba(255,255,255,0.1);
            border-radius: 4px;
        }
        
        /* 内容区域紧贴header */
        .page-content {
            margin-top: -76px; /* 负边距让内容上移 */
        }
        
        /* 英雄区域紧贴header */
        .hero-section {
            margin-top: 50px; /* 抵消body的padding-top */
            border-radius: 0 !important;
        }
        
        /* 分类下拉菜单样式 */
        .dropdown-menu {
            border-radius: 8px;
            box-shadow: 0 4px 20px rgba(0,0,0,0.15);
            border: 1px solid rgba(0,0,0,0.1);
        }
        
        .dropdown-item {
            padding: 8px 16px;
            transition: all 0.2s ease;
        }
        
        .dropdown-item:hover {
            background-color: #f8f9fa;
            padding-left: 20px;
        }
        
        /* 搜索框样式 */
        .navbar .input-group {
            max-width: 300px;
        }
        
        @media (max-width: 768px) {
            body {
                padding-top: 70px;
            }
            
            .page-content {
                margin-top: -70px;
            }
            
            .hero-section {
                margin-top: 44px;
            }
            
            .navbar .input-group {
                max-width: 100%;
                margin-top: 10px;
            }
        }
        
        @media (max-width: 576px) {
            .navbar-brand {
                font-size: 1rem;
            }
            
            .nav-link {
                padding: 0.5rem 0.75rem;
            }
            
            .dropdown-menu {
                border: none;
                box-shadow: none;
                background-color: rgba(255,255,255,0.05);
            }
            
            .dropdown-item {
                color: rgba(255,255,255,0.8);
                padding: 6px 15px;
            }
            
            .dropdown-item:hover {
                background-color: rgba(255,255,255,0.1);
                color: white;
            }
        }