:root {
            --primary-color: #0066cc;
            --secondary-color: #003366;
            --accent-color: #ff9900;
            --light-color: #f8f9fa;
            --dark-color: #343a40;
        }
        body {
            font-family: "Microsoft YaHei", "Segoe UI", sans-serif;
            line-height: 1.8;
            color: #333;
            overflow-x: hidden;
        }
        .navbar-brand {
            font-weight: 700;
            font-size: 1.8rem;
            color: var(--primary-color);
        }
        .navbar-nav .nav-link {
            font-weight: 500;
            padding: 0.5rem 1rem;
            transition: color 0.3s ease;
        }
        .navbar-nav .nav-link:hover {
            color: var(--accent-color);
        }
        .hero-section {
            background: linear-gradient(rgba(0, 51, 102, 0.85), rgba(0, 102, 204, 0.9)), url('https://images.unsplash.com/photo-1541888946425-d81bb19240f5?ixlib=rb-4.0.3&auto=format&fit=crop&w=1950&q=80') no-repeat center center;
            background-size: cover;
            color: white;
            padding: 150px 0;
        }
        .hero-section h1 {
            font-size: 3.5rem;
            font-weight: 700;
            margin-bottom: 1.5rem;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
        }
        .hero-section p {
            font-size: 1.3rem;
            max-width: 800px;
            margin: 0 auto 2rem;
        }
        .section-title {
            color: var(--secondary-color);
            font-weight: 700;
            margin-bottom: 3rem;
            position: relative;
            padding-bottom: 15px;
        }
        .section-title::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 100px;
            height: 4px;
            background: var(--accent-color);
            border-radius: 2px;
        }
        .service-card, .case-card, .news-card {
            border: none;
            border-radius: 15px;
            overflow: hidden;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            height: 100%;
            box-shadow: 0 10px 20px rgba(0,0,0,0.08);
        }
        .service-card:hover, .case-card:hover, .news-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 20px 40px rgba(0,0,0,0.15);
        }
        .service-icon {
            font-size: 3rem;
            color: var(--primary-color);
            margin-bottom: 1.5rem;
        }
        .case-card img, .news-card img {
            height: 250px;
            object-fit: cover;
            transition: transform 0.5s ease;
        }
        .case-card:hover img, .news-card:hover img {
            transform: scale(1.05);
        }
        .contact-info i {
            color: var(--accent-color);
            margin-right: 10px;
            font-size: 1.5rem;
            vertical-align: middle;
        }
        .contact-form .form-control {
            border-radius: 10px;
            padding: 12px 15px;
            border: 1px solid #ddd;
            transition: border-color 0.3s ease;
        }
        .contact-form .form-control:focus {
            border-color: var(--primary-color);
            box-shadow: 0 0 0 0.25rem rgba(0,102,204,0.25);
        }
        .btn-primary {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
            padding: 12px 30px;
            border-radius: 50px;
            font-weight: 600;
            transition: all 0.3s ease;
        }
        .btn-primary:hover {
            background-color: var(--secondary-color);
            border-color: var(--secondary-color);
            transform: translateY(-3px);
        }
        .friendlink {
            background-color: var(--light-color);
            padding: 60px 0;
        }
        .flink {
            display: inline-block;
            padding: 12px 25px;
            margin: 10px;
            background: white;
            border-radius: 10px;
            color: var(--dark-color);
            text-decoration: none;
            font-weight: 500;
            border: 2px solid transparent;
            transition: all 0.3s ease;
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
        }
        .flink:hover {
            border-color: var(--accent-color);
            color: var(--primary-color);
            transform: translateY(-5px);
        }
        footer {
            background-color: var(--secondary-color);
            color: white;
            padding: 40px 0 20px;
        }
        footer a {
            color: #ccc;
            text-decoration: none;
            transition: color 0.3s ease;
        }
        footer a:hover {
            color: var(--accent-color);
        }
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 50px;
            height: 50px;
            background: var(--accent-color);
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            text-decoration: none;
            opacity: 0;
            transition: opacity 0.3s ease, transform 0.3s ease;
            z-index: 1000;
        }
        .back-to-top.show {
            opacity: 1;
        }
        .back-to-top:hover {
            transform: scale(1.1);
        }
        @media (max-width: 768px) {
            .hero-section h1 {
                font-size: 2.5rem;
            }
            .hero-section p {
                font-size: 1.1rem;
            }
            .section-title {
                font-size: 2rem;
            }
        }