:root {
            --primary-color: #1a5f7a;
            --secondary-color: #2a9d8f;
            --accent-color: #e9c46a;
            --light-color: #f8f9fa;
            --dark-color: #343a40;
            --transition: all 0.3s ease;
        }
        body {
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
            color: #333;
            overflow-x: hidden;
        }
        h1, h2, h3, h4, h5 {
            font-weight: 700;
            color: var(--primary-color);
        }
        .navbar {
            background-color: rgba(255, 255, 255, 0.95);
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
            padding: 1rem 0;
            transition: var(--transition);
        }
        .navbar-brand {
            font-weight: 700;
            font-size: 1.8rem;
            color: var(--primary-color);
        }
        .navbar-brand span {
            color: var(--secondary-color);
        }
        .nav-link {
            font-weight: 600;
            margin: 0 5px;
            color: var(--dark-color);
            transition: var(--transition);
        }
        .nav-link:hover, .nav-link.active {
            color: var(--primary-color);
        }
        .hero {
            background: linear-gradient(rgba(26, 95, 122, 0.85), rgba(42, 157, 143, 0.8)), url('https://images.unsplash.com/photo-1559757148-5c350d0d3c56?ixlib=rb-4.0.3&auto=format&fit=crop&w=2070&q=80') center/cover no-repeat;
            color: white;
            padding: 120px 0 80px;
            position: relative;
        }
        .hero h1 {
            color: white;
            font-size: 3.5rem;
            margin-bottom: 1.5rem;
        }
        .hero p {
            font-size: 1.2rem;
            max-width: 700px;
            margin: 0 auto 2rem;
        }
        .section-title {
            position: relative;
            margin-bottom: 3rem;
            text-align: center;
        }
        .section-title:after {
            content: '';
            position: absolute;
            width: 80px;
            height: 4px;
            background: var(--secondary-color);
            bottom: -15px;
            left: 50%;
            transform: translateX(-50%);
            border-radius: 2px;
        }
        .card {
            border: none;
            border-radius: 10px;
            overflow: hidden;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
            transition: var(--transition);
            height: 100%;
        }
        .card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
        }
        .card-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
        }
        .service-card {
            border-top: 4px solid var(--secondary-color);
        }
        .product-card {
            border-top: 4px solid var(--accent-color);
        }
        .btn-primary {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
            padding: 10px 25px;
            font-weight: 600;
        }
        .btn-primary:hover {
            background-color: #14495e;
            border-color: #14495e;
        }
        .btn-secondary {
            background-color: var(--secondary-color);
            border-color: var(--secondary-color);
            padding: 10px 25px;
            font-weight: 600;
        }
        .btn-secondary:hover {
            background-color: #21867a;
            border-color: #21867a;
        }
        .feature-box {
            padding: 30px;
            background: white;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
            height: 100%;
            transition: var(--transition);
        }
        .feature-box:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
        }
        .about-img {
            border-radius: 10px;
            overflow: hidden;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
        }
        .stats-box {
            background: var(--primary-color);
            color: white;
            padding: 30px;
            border-radius: 10px;
            text-align: center;
        }
        .stats-number {
            font-size: 3rem;
            font-weight: 700;
            margin-bottom: 0.5rem;
        }
        .timeline {
            position: relative;
            padding-left: 30px;
        }
        .timeline:before {
            content: '';
            position: absolute;
            left: 0;
            top: 0;
            bottom: 0;
            width: 4px;
            background: var(--secondary-color);
            border-radius: 2px;
        }
        .timeline-item {
            position: relative;
            margin-bottom: 30px;
        }
        .timeline-item:before {
            content: '';
            position: absolute;
            left: -36px;
            top: 5px;
            width: 16px;
            height: 16px;
            border-radius: 50%;
            background: var(--secondary-color);
            border: 3px solid white;
            box-shadow: 0 0 0 3px var(--secondary-color);
        }
        .contact-info-box {
            background: var(--light-color);
            padding: 25px;
            border-radius: 10px;
            margin-bottom: 20px;
            height: 100%;
        }
        .contact-icon {
            font-size: 2rem;
            color: var(--primary-color);
            margin-bottom: 1rem;
        }
        .flink {
            display: inline-block;
            background: var(--light-color);
            padding: 10px 20px;
            margin: 5px 10px;
            border-radius: 5px;
            color: var(--dark-color);
            text-decoration: none;
            transition: var(--transition);
        }
        .flink:hover {
            background: var(--primary-color);
            color: white;
            transform: translateY(-3px);
        }
        .footer {
            background: var(--dark-color);
            color: white;
            padding: 60px 0 20px;
        }
        .footer a {
            color: #ddd;
            text-decoration: none;
            transition: var(--transition);
        }
        .footer a:hover {
            color: white;
        }
        .footer-bottom {
            border-top: 1px solid #444;
            padding-top: 20px;
            margin-top: 40px;
        }
        .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: 1.2rem;
            text-decoration: none;
            opacity: 0;
            visibility: hidden;
            transition: var(--transition);
            z-index: 1000;
        }
        .back-to-top.active {
            opacity: 1;
            visibility: visible;
        }
        .back-to-top:hover {
            background: var(--secondary-color);
            color: white;
        }
        @media (max-width: 768px) {
            .hero h1 {
                font-size: 2.5rem;
            }
            .hero p {
                font-size: 1rem;
            }
            .section-title {
                font-size: 1.8rem;
            }
        }