:root {
            --primary-color: #0056b3;
            --secondary-color: #6c757d;
            --accent-color: #28a745;
            --dark-color: #343a40;
            --light-color: #f8f9fa;
            --border-radius: 8px;
            --box-shadow: 0 5px 15px rgba(0,0,0,0.08);
            --transition: all 0.3s ease;
        }
        body {
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
            color: #333;
            line-height: 1.6;
            overflow-x: hidden;
        }
        .navbar-brand {
            font-weight: 700;
            font-size: 1.8rem;
        }
        .nav-link {
            font-weight: 500;
            transition: var(--transition);
            position: relative;
        }
        .nav-link:hover {
            color: var(--primary-color) !important;
        }
        .nav-link::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 0;
            height: 2px;
            background: var(--primary-color);
            transition: var(--transition);
        }
        .nav-link:hover::after {
            width: 80%;
        }
        .hero-section {
            background: linear-gradient(rgba(0, 40, 80, 0.85), rgba(0, 60, 120, 0.9)), url('https://images.unsplash.com/photo-1581094794329-c8112a89af12?ixlib=rb-4.0.3&auto=format&fit=crop&w=2070&q=80') center/cover no-repeat;
            color: white;
            padding: 120px 0;
            margin-top: 76px;
        }
        .section-title {
            position: relative;
            padding-bottom: 15px;
            margin-bottom: 40px;
            text-align: center;
            font-weight: 700;
        }
        .section-title::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 80px;
            height: 4px;
            background: var(--primary-color);
            border-radius: 2px;
        }
        .card {
            border: none;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
            transition: var(--transition);
            height: 100%;
            overflow: hidden;
        }
        .card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0,0,0,0.15);
        }
        .card-img-top {
            height: 220px;
            object-fit: cover;
            transition: var(--transition);
        }
        .card:hover .card-img-top {
            transform: scale(1.05);
        }
        .icon-box {
            width: 70px;
            height: 70px;
            border-radius: 50%;
            background: var(--primary-color);
            color: white;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 20px;
            font-size: 1.8rem;
        }
        .btn-primary {
            background-color: var(--primary-color);
            border-color: var(--primary-color);
            padding: 10px 25px;
            border-radius: 30px;
            font-weight: 600;
            transition: var(--transition);
        }
        .btn-primary:hover {
            background-color: #004494;
            border-color: #004494;
            transform: translateY(-3px);
        }
        .feature-list li {
            padding: 8px 0;
            border-bottom: 1px dashed #eee;
        }
        .feature-list li i {
            color: var(--accent-color);
            margin-right: 10px;
        }
        .contact-info-box {
            background: var(--light-color);
            border-left: 4px solid var(--primary-color);
            padding: 20px;
            border-radius: 0 var(--border-radius) var(--border-radius) 0;
            margin-bottom: 20px;
        }
        .flink {
            display: inline-block;
            background: var(--light-color);
            padding: 10px 20px;
            margin: 5px 10px;
            border-radius: 30px;
            color: var(--dark-color);
            text-decoration: none;
            transition: var(--transition);
            border: 1px solid #ddd;
        }
        .flink:hover {
            background: var(--primary-color);
            color: white;
            transform: translateY(-3px);
            text-decoration: none;
        }
        footer {
            background: var(--dark-color);
            color: #aaa;
        }
        footer a {
            color: #ddd;
            text-decoration: none;
            transition: var(--transition);
        }
        footer a:hover {
            color: white;
            text-decoration: underline;
        }
        .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;
            text-decoration: none;
            font-size: 1.5rem;
            z-index: 1000;
            opacity: 0.8;
            transition: var(--transition);
        }
        .back-to-top:hover {
            opacity: 1;
            color: white;
            transform: translateY(-5px);
        }
        @media (max-width: 768px) {
            .hero-section {
                padding: 80px 0;
                margin-top: 66px;
            }
            .section-title {
                font-size: 1.8rem;
            }
            .card-img-top {
                height: 180px;
            }
        }