:root {
            --primary-color: #0d6efd;
            --secondary-color: #6c757d;
            --accent-color: #198754;
            --dark-color: #212529;
            --light-color: #f8f9fa;
        }
        body {
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
            color: var(--dark-color);
            line-height: 1.8;
        }
        h1, h2, h3, h4, h5, h6 {
            font-weight: 700;
            margin-bottom: 1rem;
        }
        .hero-section {
            background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
            color: white;
            padding: 6rem 0;
        }
        .section-padding {
            padding: 5rem 0;
        }
        .card {
            border: none;
            border-radius: 15px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.08);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            height: 100%;
        }
        .card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 40px rgba(0,0,0,0.15);
        }
        .btn-primary {
            background-color: var(--primary-color);
            border: none;
            padding: 0.75rem 2rem;
            border-radius: 50px;
            font-weight: 600;
            transition: all 0.3s ease;
        }
        .btn-primary:hover {
            background-color: #0b5ed7;
            transform: scale(1.05);
        }
        .navbar {
            box-shadow: 0 4px 12px rgba(0,0,0,0.1);
            padding: 1rem 0;
        }
        .navbar-brand {
            font-size: 1.8rem;
            font-weight: 800;
            color: var(--primary-color) !important;
        }
        .nav-link {
            font-weight: 500;
            margin: 0 0.5rem;
            transition: color 0.3s ease;
        }
        .nav-link:hover {
            color: var(--primary-color) !important;
        }
        .footer {
            background-color: var(--dark-color);
            color: var(--light-color);
            padding: 3rem 0 1.5rem;
        }
        .footer a {
            color: #adb5bd;
            text-decoration: none;
            transition: color 0.3s ease;
        }
        .footer a:hover {
            color: white;
        }
        .friendlink {
            background-color: #f1f5f9;
            padding: 3rem 0;
        }
        .flink {
            display: inline-block;
            margin: 0.5rem 1rem;
            padding: 0.5rem 1.5rem;
            background: white;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
            transition: all 0.3s ease;
            color: var(--dark-color);
            text-decoration: none;
            font-weight: 500;
        }
        .flink:hover {
            background: var(--primary-color);
            color: white;
            transform: translateY(-3px);
        }
        .img-hover {
            overflow: hidden;
            border-radius: 15px;
        }
        .img-hover img {
            transition: transform 0.5s ease;
        }
        .img-hover img:hover {
            transform: scale(1.05);
        }
        @media (max-width: 768px) {
            .hero-section {
                padding: 4rem 0;
                text-align: center;
            }
            .section-padding {
                padding: 3rem 0;
            }
            .display-4 {
                font-size: 2.5rem;
            }
        }