:root {
            --primary-color: #c62828;
            --secondary-color: #263238;
            --accent-color: #ff9800;
            --light-color: #f5f5f5;
            --dark-color: #212121;
            --transition: all 0.3s ease;
        }
        body {
            font-family: 'Microsoft YaHei', 'Segoe UI', sans-serif;
            line-height: 1.6;
            color: #333;
            overflow-x: hidden;
        }
        .navbar-brand {
            font-weight: 700;
            font-size: 1.8rem;
        }
        .navbar-brand span {
            color: var(--primary-color);
        }
        .hero-section {
            background: linear-gradient(rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.7)), url('https://images.unsplash.com/photo-1581094794329-c8112a89af12?ixlib=rb-4.0.3&auto=format&fit=crop&w=1920&q=80') center/cover no-repeat;
            color: white;
            padding: 150px 0 100px;
            position: relative;
        }
        .hero-section h1 {
            font-size: 3.5rem;
            font-weight: 700;
            margin-bottom: 20px;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
        }
        @media (max-width: 768px) {
            .hero-section h1 {
                font-size: 2.5rem;
            }
            .hero-section {
                padding: 100px 0 60px;
            }
        }
        .section-title {
            position: relative;
            margin-bottom: 50px;
            text-align: center;
        }
        .section-title h2 {
            font-weight: 700;
            color: var(--secondary-color);
            display: inline-block;
            padding-bottom: 15px;
        }
        .section-title h2:after {
            content: '';
            position: absolute;
            width: 80px;
            height: 4px;
            background: var(--primary-color);
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
        }
        .card-hover {
            transition: var(--transition);
            height: 100%;
            border: 1px solid #eee;
        }
        .card-hover:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0,0,0,0.1);
            border-color: var(--primary-color);
        }
        .btn-primary-custom {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
            padding: 12px 30px;
            font-weight: 600;
            transition: var(--transition);
        }
        .btn-primary-custom:hover {
            background-color: #a01515;
            border-color: #a01515;
            transform: translateY(-3px);
            box-shadow: 0 5px 15px rgba(198, 40, 40, 0.3);
        }
        .service-icon {
            font-size: 3rem;
            color: var(--primary-color);
            margin-bottom: 20px;
        }
        .product-img {
            height: 220px;
            object-fit: cover;
            transition: var(--transition);
        }
        .product-card:hover .product-img {
            transform: scale(1.05);
        }
        .bg-light-custom {
            background-color: #f9f9f9;
        }
        .contact-info-box {
            padding: 30px;
            background: white;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
            height: 100%;
            transition: var(--transition);
        }
        .contact-info-box:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 30px rgba(0,0,0,0.1);
        }
        .contact-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 20px;
        }
        footer {
            background-color: var(--secondary-color);
            color: white;
            padding: 60px 0 30px;
        }
        footer a {
            color: #ccc;
            text-decoration: none;
            transition: var(--transition);
        }
        footer a:hover {
            color: white;
            padding-left: 5px;
        }
        .footer-bottom {
            border-top: 1px solid #444;
            padding-top: 20px;
            margin-top: 40px;
        }
        .flink {
            display: inline-block;
            padding: 8px 15px;
            margin: 5px;
            background: rgba(255,255,255,0.1);
            border-radius: 5px;
            transition: var(--transition);
            color: #ddd;
        }
        .flink:hover {
            background: var(--primary-color);
            color: white;
            transform: translateY(-3px);
            text-decoration: none;
        }
        .timeline {
            position: relative;
            padding-left: 30px;
            margin-bottom: 30px;
        }
        .timeline:before {
            content: '';
            position: absolute;
            left: 0;
            top: 0;
            bottom: 0;
            width: 3px;
            background: var(--primary-color);
        }
        .timeline-item {
            position: relative;
            margin-bottom: 30px;
        }
        .timeline-item:before {
            content: '';
            position: absolute;
            left: -36px;
            top: 5px;
            width: 15px;
            height: 15px;
            border-radius: 50%;
            background: var(--primary-color);
            border: 3px solid white;
            box-shadow: 0 0 0 3px var(--primary-color);
        }
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 50px;
            height: 50px;
            background: var(--primary-color);
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            z-index: 1000;
            opacity: 0;
            visibility: hidden;
            transition: var(--transition);
        }
        .back-to-top.active {
            opacity: 1;
            visibility: visible;
        }
        .back-to-top:hover {
            background: #a01515;
            color: white;
            transform: translateY(-5px);
        }
        .nav-link {
            font-weight: 500;
            transition: var(--transition);
            margin: 0 5px;
        }
        .nav-link:hover, .nav-link.active {
            color: var(--primary-color) !important;
        }
        .sticky-nav {
            background-color: rgba(255, 255, 255, 0.95);
            box-shadow: 0 5px 20px rgba(0,0,0,0.1);
            transition: var(--transition);
        }