:root {
            --primary-color: #0066cc;
            --secondary-color: #00a859;
            --accent-color: #ff6600;
            --dark-color: #1a365d;
            --light-color: #f8f9fa;
            --text-color: #333;
            --gray-color: #6c757d;
        }
        body {
            font-family: 'Helvetica Neue', 'Microsoft YaHei', Arial, sans-serif;
            color: var(--text-color);
            line-height: 1.7;
            overflow-x: hidden;
        }
        h1, h2, h3, h4, h5, h6 {
            font-weight: 700;
            color: var(--dark-color);
            margin-bottom: 1rem;
        }
        .section-title {
            position: relative;
            padding-bottom: 15px;
            margin-bottom: 3rem;
            text-align: center;
        }
        .section-title:after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 80px;
            height: 4px;
            background: var(--secondary-color);
            border-radius: 2px;
        }
        .section-title.left:after {
            left: 0;
            transform: none;
        }
        .navbar {
            background-color: rgba(255, 255, 255, 0.98);
            box-shadow: 0 2px 15px rgba(0, 0, 0, 0.1);
            padding: 1rem 0;
            transition: all 0.3s ease;
        }
        .navbar-brand {
            font-weight: 800;
            font-size: 1.8rem;
            color: var(--primary-color);
        }
        .navbar-brand span {
            color: var(--secondary-color);
        }
        .nav-link {
            font-weight: 600;
            color: var(--dark-color) !important;
            margin: 0 0.5rem;
            padding: 0.5rem 1rem !important;
            border-radius: 4px;
            transition: all 0.3s ease;
        }
        .nav-link:hover, .nav-link.active {
            color: white !important;
            background-color: var(--primary-color);
        }
        .hero-section {
            background: linear-gradient(rgba(0, 50, 100, 0.85), rgba(0, 80, 120, 0.9)), url('https://images.unsplash.com/photo-1579684385127-1ef15d508118?ixlib=rb-4.0.3&auto=format&fit=crop&w=1920&q=80');
            background-size: cover;
            background-position: center;
            color: white;
            padding: 150px 0 100px;
            margin-top: 76px;
        }
        .hero-title {
            font-size: 3.5rem;
            font-weight: 800;
            margin-bottom: 1.5rem;
            text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.3);
        }
        @media (max-width: 768px) {
            .hero-title {
                font-size: 2.5rem;
            }
        }
        .hero-subtitle {
            font-size: 1.3rem;
            margin-bottom: 2.5rem;
            opacity: 0.9;
        }
        .feature-card, .product-card, .news-card {
            border-radius: 10px;
            overflow: hidden;
            box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
            transition: all 0.3s ease;
            height: 100%;
            background: white;
        }
        .feature-card:hover, .product-card:hover, .news-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
        }
        .feature-icon {
            width: 80px;
            height: 80px;
            border-radius: 50%;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 1.5rem;
            color: white;
            font-size: 2rem;
        }
        .product-img {
            height: 220px;
            object-fit: cover;
            width: 100%;
        }
        .product-card .card-body {
            padding: 1.5rem;
        }
        .product-title {
            color: var(--dark-color);
            font-size: 1.3rem;
            margin-bottom: 0.8rem;
        }
        .news-img {
            height: 200px;
            object-fit: cover;
            width: 100%;
        }
        .news-date {
            color: var(--gray-color);
            font-size: 0.9rem;
            margin-bottom: 0.5rem;
        }
        .news-title {
            font-size: 1.2rem;
            margin-bottom: 1rem;
            color: var(--dark-color);
        }
        .contact-info {
            background: var(--light-color);
            padding: 2rem;
            border-radius: 10px;
            height: 100%;
        }
        .contact-icon {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            background: var(--primary-color);
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-size: 1.5rem;
            margin-bottom: 1.5rem;
        }
        .friendlink {
            background-color: #f8f9fa;
            padding: 80px 0;
        }
        .flink {
            display: inline-block;
            padding: 10px 25px;
            margin: 8px;
            background: white;
            border-radius: 8px;
            color: var(--dark-color);
            font-weight: 500;
            text-decoration: none;
            box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
            transition: all 0.3s ease;
            border: 1px solid #eaeaea;
        }
        .flink:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
            color: var(--primary-color);
            border-color: var(--primary-color);
        }
        .footer {
            background-color: var(--dark-color);
            color: white;
            padding: 60px 0 30px;
        }
        .footer a {
            color: #ddd;
            text-decoration: none;
            transition: color 0.3s ease;
        }
        .footer a:hover {
            color: white;
        }
        .footer-title {
            color: white;
            font-size: 1.3rem;
            margin-bottom: 1.5rem;
            position: relative;
            padding-bottom: 10px;
        }
        .footer-title:after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 50px;
            height: 3px;
            background: var(--secondary-color);
        }
        .footer-links li {
            margin-bottom: 10px;
        }
        .copyright {
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            padding-top: 20px;
            margin-top: 40px;
            text-align: center;
            color: #aaa;
            font-size: 0.9rem;
        }
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 50px;
            height: 50px;
            border-radius: 50%;
            background-color: var(--primary-color);
            color: white;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.2rem;
            z-index: 1000;
            cursor: pointer;
            opacity: 0;
            visibility: hidden;
            transition: all 0.3s ease;
            box-shadow: 0 3px 10px rgba(0, 102, 204, 0.3);
        }
        .back-to-top.active {
            opacity: 1;
            visibility: visible;
        }
        .back-to-top:hover {
            background-color: var(--secondary-color);
            transform: translateY(-5px);
        }
        .fade-in {
            opacity: 0;
            transform: translateY(30px);
            transition: opacity 0.8s ease, transform 0.8s ease;
        }
        .fade-in.visible {
            opacity: 1;
            transform: translateY(0);
        }
        @media (max-width: 768px) {
            .hero-section {
                padding: 100px 0 60px;
                text-align: center;
            }
            .section-title {
                font-size: 1.8rem;
            }
            .contact-form {
                margin-top: 2rem;
            }
        }