:root {
            --primary-color: #0056b3;
            --secondary-color: #28a745;
            --accent-color: #ffc107;
            --dark-color: #343a40;
            --light-color: #f8f9fa;
        }
        body {
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
            color: #333;
            line-height: 1.8;
            overflow-x: hidden;
        }
        .navbar-brand {
            font-weight: 700;
            font-size: 1.8rem;
            color: var(--primary-color);
        }
        .nav-link {
            font-weight: 500;
            transition: color 0.3s;
        }
        .nav-link:hover {
            color: var(--primary-color);
        }
        .hero-section {
            background: linear-gradient(rgba(0, 84, 179, 0.85), rgba(0, 84, 179, 0.9)), url('https://images.unsplash.com/photo-1451187580459-43490279c0fa?ixlib=rb-4.0.3&auto=format&fit=crop&w=1352&q=80') center/cover no-repeat;
            color: white;
            padding: 120px 0;
            text-align: center;
        }
        .hero-section h1 {
            font-size: 3.5rem;
            font-weight: 800;
            margin-bottom: 20px;
        }
        .section-title {
            font-size: 2.5rem;
            font-weight: 700;
            color: var(--primary-color);
            margin-bottom: 40px;
            position: relative;
            display: inline-block;
        }
        .section-title::after {
            content: '';
            position: absolute;
            bottom: -10px;
            left: 50%;
            transform: translateX(-50%);
            width: 80px;
            height: 4px;
            background-color: var(--accent-color);
        }
        .card {
            border: none;
            border-radius: 15px;
            overflow: hidden;
            transition: transform 0.3s, box-shadow 0.3s;
            height: 100%;
        }
        .card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
        }
        .card-img-top {
            height: 220px;
            object-fit: cover;
        }
        .btn-primary {
            background-color: var(--primary-color);
            border: none;
            padding: 12px 30px;
            border-radius: 50px;
            font-weight: 600;
            transition: background-color 0.3s, transform 0.3s;
        }
        .btn-primary:hover {
            background-color: #004494;
            transform: scale(1.05);
        }
        .footer {
            background-color: var(--dark-color);
            color: var(--light-color);
            padding: 60px 0 20px;
        }
        .footer a {
            color: #ccc;
            text-decoration: none;
            transition: color 0.3s;
        }
        .footer a:hover {
            color: white;
        }
        .friendlink {
            background-color: #f8f9fa;
            padding: 40px 0;
        }
        .flink {
            display: inline-block;
            margin: 10px 15px;
            padding: 10px 20px;
            background: white;
            border-radius: 10px;
            color: var(--primary-color);
            font-weight: 600;
            text-decoration: none;
            transition: all 0.3s;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
        }
        .flink:hover {
            background-color: var(--primary-color);
            color: white;
            transform: translateY(-3px);
        }
        .contact-info i {
            color: var(--secondary-color);
            margin-right: 10px;
        }
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            background-color: var(--primary-color);
            color: white;
            width: 50px;
            height: 50px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            text-decoration: none;
            opacity: 0.8;
            transition: opacity 0.3s;
            z-index: 1000;
        }
        .back-to-top:hover {
            opacity: 1;
        }
        @media (max-width: 768px) {
            .hero-section h1 {
                font-size: 2.5rem;
            }
            .section-title {
                font-size: 2rem;
            }
            .card-img-top {
                height: 180px;
            }
        }