:root {
            --primary-color: #1a365d;
            --secondary-color: #2d74b4;
            --accent-color: #e63946;
            --light-color: #f8f9fa;
            --dark-color: #212529;
            --gray-color: #6c757d;
            --transition: all 0.3s ease;
        }
        body {
            font-family: 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
            color: var(--dark-color);
            line-height: 1.7;
            overflow-x: hidden;
        }
        h1, h2, h3, h4, h5, h6 {
            font-weight: 700;
            color: var(--primary-color);
        }
        .section-title {
            position: relative;
            padding-bottom: 15px;
            margin-bottom: 50px;
        }
        .section-title:after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 80px;
            height: 4px;
            background: var(--accent-color);
        }
        .section-title.center:after {
            left: 50%;
            transform: translateX(-50%);
        }
        .navbar {
            background-color: rgba(255, 255, 255, 0.95);
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            padding: 15px 0;
            transition: var(--transition);
        }
        .navbar-brand {
            font-weight: 800;
            font-size: 1.8rem;
            color: var(--primary-color);
        }
        .navbar-brand span {
            color: var(--accent-color);
        }
        .nav-link {
            font-weight: 600;
            color: var(--primary-color) !important;
            margin: 0 10px;
            padding: 8px 16px !important;
            border-radius: 4px;
            transition: var(--transition);
        }
        .nav-link:hover, .nav-link.active {
            background-color: var(--primary-color);
            color: white !important;
        }
        .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');
            background-size: cover;
            background-position: center;
            background-attachment: fixed;
            color: white;
            padding: 180px 0 120px;
            min-height: 100vh;
            display: flex;
            align-items: center;
        }
        .hero-content h1 {
            color: white;
            font-size: 3.5rem;
            margin-bottom: 25px;
            text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.5);
        }
        @media (max-width: 768px) {
            .hero-content h1 {
                font-size: 2.5rem;
            }
        }
        .hero-content p {
            font-size: 1.2rem;
            margin-bottom: 35px;
            max-width: 700px;
        }
        .btn-primary {
            background-color: var(--accent-color);
            border-color: var(--accent-color);
            padding: 12px 30px;
            font-weight: 600;
            border-radius: 4px;
            transition: var(--transition);
        }
        .btn-primary:hover {
            background-color: #c53030;
            border-color: #c53030;
            transform: translateY(-3px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
        }
        .feature-card {
            background: white;
            border-radius: 10px;
            padding: 40px 30px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
            transition: var(--transition);
            height: 100%;
            border-top: 5px solid transparent;
        }
        .feature-card:hover {
            transform: translateY(-10px);
            border-top-color: var(--accent-color);
            box-shadow: 0 15px 35px rgba(0, 0, 0, 0.12);
        }
        .feature-icon {
            width: 80px;
            height: 80px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 25px;
            color: white;
            font-size: 2rem;
        }
        .product-card {
            border-radius: 10px;
            overflow: hidden;
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
            transition: var(--transition);
            height: 100%;
        }
        .product-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 35px rgba(0, 0, 0,0.15);
        }
        .product-img {
            height: 250px;
            overflow: hidden;
        }
        .product-img img {
            width: 100%;
            height: 100%;
            object-fit: cover;
            transition: var(--transition);
        }
        .product-card:hover .product-img img {
            transform: scale(1.05);
        }
        .timeline {
            position: relative;
            padding-left: 30px;
        }
        .timeline:before {
            content: '';
            position: absolute;
            left: 0;
            top: 0;
            bottom: 0;
            width: 4px;
            background: linear-gradient(to bottom, var(--primary-color), var(--secondary-color));
        }
        .timeline-item {
            position: relative;
            margin-bottom: 40px;
            padding-left: 30px;
        }
        .timeline-item:before {
            content: '';
            position: absolute;
            left: -38px;
            top: 5px;
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background-color: var(--accent-color);
            border: 4px solid white;
            box-shadow: 0 0 0 3px var(--accent-color);
        }
        .contact-card {
            background: white;
            border-radius: 10px;
            padding: 30px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
            height: 100%;
            text-align: center;
            transition: var(--transition);
        }
        .contact-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 35px rgba(0, 0, 0, 0.12);
        }
        .contact-icon {
            width: 70px;
            height: 70px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 25px;
            color: white;
            font-size: 1.8rem;
        }
        friendlink {
            display: block;
            width: 100%;
            margin-top: 40px;
            padding-top: 40px;
            border-top: 1px solid #eee;
        }
        .flink {
            display: inline-block;
            background-color: white;
            border-radius: 6px;
            padding: 12px 25px;
            margin: 8px;
            color: var(--primary-color);
            font-weight: 500;
            text-decoration: none;
            border: 1px solid #e0e0e0;
            transition: var(--transition);
        }
        .flink:hover {
            background-color: var(--primary-color);
            color: white;
            transform: translateY(-3px);
            box-shadow: 0 8px 20px rgba(26, 54, 93, 0.15);
            border-color: var(--primary-color);
        }
        footer {
            background-color: var(--primary-color);
            color: rgba(255, 255, 255, 0.85);
            padding-top: 70px;
        }
        footer h5 {
            color: white;
            margin-bottom: 25px;
            font-size: 1.2rem;
        }
        footer a {
            color: rgba(255, 255, 255, 0.85);
            text-decoration: none;
            transition: var(--transition);
        }
        footer a:hover {
            color: white;
            padding-left: 5px;
        }
        .footer-bottom {
            background-color: rgba(0, 0, 0, 0.2);
            padding: 20px 0;
            margin-top: 60px;
        }
        @media (max-width: 768px) {
            .hero-section {
                padding: 140px 0 80px;
                text-align: center;
            }
            .section-title {
                text-align: center;
            }
            .section-title:after {
                left: 50%;
                transform: translateX(-50%);
            }
            .navbar-nav {
                text-align: center;
                padding-top: 20px;
            }
            .nav-link {
                margin: 5px 0;
            }
        }
        .fade-in {
            opacity: 0;
            transform: translateY(30px);
            transition: opacity 0.6s ease, transform 0.6s ease;
        }
        .fade-in.visible {
            opacity: 1;
            transform: translateY(0);
        }
        .scroll-progress {
            position: fixed;
            top: 0;
            left: 0;
            width: 0%;
            height: 4px;
            background: linear-gradient(to right, var(--primary-color), var(--accent-color));
            z-index: 9999;
            transition: width 0.3s ease;
        }
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 50px;
            height: 50px;
            background-color: var(--accent-color);
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.2rem;
            cursor: pointer;
            opacity: 0;
            visibility: hidden;
            transition: var(--transition);
            z-index: 99;
        }
        .back-to-top.show {
            opacity: 1;
            visibility: visible;
        }
        .back-to-top:hover {
            background-color: var(--primary-color);
            transform: translateY(-5px);
        }