:root {
            --primary-color: #2c6bb3;
            --secondary-color: #f8b500;
            --accent-color: #34c759;
            --dark-color: #1a365d;
            --light-color: #f8f9fa;
            --text-color: #333;
            --text-light: #666;
            --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            --transition: all 0.3s ease;
        }
        body {
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
            color: var(--text-color);
            line-height: 1.7;
            overflow-x: hidden;
        }
        h1, h2, h3, h4, h5 {
            font-weight: 700;
            color: var(--dark-color);
        }
        .navbar {
            background-color: rgba(255, 255, 255, 0.98);
            box-shadow: var(--shadow);
            padding-top: 0.8rem;
            padding-bottom: 0.8rem;
            transition: var(--transition);
        }
        .navbar-brand {
            font-weight: 800;
            font-size: 1.8rem;
            color: var(--primary-color) !important;
        }
        .nav-link {
            font-weight: 600;
            color: var(--dark-color) !important;
            margin: 0 0.5rem;
            position: relative;
            padding: 0.5rem 0 !important;
        }
        .nav-link::after {
            content: '';
            position: absolute;
            width: 0;
            height: 3px;
            bottom: 0;
            left: 0;
            background-color: var(--secondary-color);
            transition: var(--transition);
        }
        .nav-link:hover::after, .nav-link.active::after {
            width: 100%;
        }
        .hero-section {
            background: linear-gradient(135deg, rgba(44, 107, 179, 0.9) 0%, rgba(26, 54, 93, 0.95) 100%), url('https://images.unsplash.com/photo-1523050854058-8df90110c9f1?ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D&auto=format&fit=crop&w=1920&q=80');
            background-size: cover;
            background-position: center;
            color: white;
            padding: 8rem 0 6rem;
            position: relative;
        }
        .hero-title {
            font-size: 3.2rem;
            font-weight: 800;
            margin-bottom: 1.5rem;
            text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
        }
        .hero-subtitle {
            font-size: 1.3rem;
            margin-bottom: 2.5rem;
            opacity: 0.9;
            max-width: 700px;
        }
        .btn-primary {
            background-color: var(--secondary-color);
            border: none;
            color: var(--dark-color);
            font-weight: 600;
            padding: 0.8rem 2rem;
            border-radius: 50px;
            transition: var(--transition);
        }
        .btn-primary:hover {
            background-color: #ffcc33;
            transform: translateY(-3px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
        }
        .btn-outline-light {
            border-radius: 50px;
            padding: 0.8rem 2rem;
            font-weight: 600;
            transition: var(--transition);
        }
        .btn-outline-light:hover {
            transform: translateY(-3px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
        }
        .section-title {
            position: relative;
            margin-bottom: 3.5rem;
            text-align: center;
        }
        .section-title::after {
            content: '';
            position: absolute;
            width: 80px;
            height: 4px;
            background-color: var(--secondary-color);
            bottom: -15px;
            left: 50%;
            transform: translateX(-50%);
            border-radius: 2px;
        }
        .feature-card {
            background: white;
            border-radius: 12px;
            padding: 2.5rem 2rem;
            height: 100%;
            box-shadow: var(--shadow);
            transition: var(--transition);
            border: 1px solid rgba(0, 0, 0, 0.05);
        }
        .feature-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.12);
        }
        .feature-icon {
            width: 80px;
            height: 80px;
            background: linear-gradient(135deg, var(--primary-color), #4a90e2);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 1.5rem;
            color: white;
            font-size: 2rem;
        }
        .feature-card h4 {
            margin-bottom: 1rem;
            color: var(--dark-color);
        }
        .stat-number {
            font-size: 3rem;
            font-weight: 800;
            color: var(--primary-color);
            line-height: 1;
            margin-bottom: 0.5rem;
        }
        .stat-label {
            font-size: 1.1rem;
            color: var(--text-light);
            font-weight: 600;
        }
        .stat-card {
            text-align: center;
            padding: 2rem;
            transition: var(--transition);
        }
        .stat-card:hover {
            transform: scale(1.05);
        }
        .course-card {
            border-radius: 12px;
            overflow: hidden;
            box-shadow: var(--shadow);
            transition: var(--transition);
            height: 100%;
            background: white;
        }
        .course-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
        }
        .course-img {
            height: 200px;
            object-fit: cover;
            width: 100%;
        }
        .course-body {
            padding: 1.8rem;
        }
        .course-title {
            font-size: 1.3rem;
            font-weight: 700;
            margin-bottom: 0.8rem;
            color: var(--dark-color);
        }
        .course-meta {
            display: flex;
            justify-content: space-between;
            margin-top: 1.2rem;
            color: var(--text-light);
            font-size: 0.9rem;
        }
        .badge-category {
            background-color: #e7f1ff;
            color: var(--primary-color);
            padding: 0.3rem 0.8rem;
            border-radius: 50px;
            font-size: 0.85rem;
            font-weight: 600;
        }
        .team-card {
            text-align: center;
            padding: 2rem;
            border-radius: 12px;
            transition: var(--transition);
            height: 100%;
            background: white;
            box-shadow: var(--shadow);
        }
        .team-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.12);
        }
        .team-img {
            width: 150px;
            height: 150px;
            border-radius: 50%;
            object-fit: cover;
            margin: 0 auto 1.5rem;
            border: 5px solid #f0f5ff;
        }
        .testimonial-card {
            background: white;
            border-radius: 12px;
            padding: 2rem;
            box-shadow: var(--shadow);
            height: 100%;
            position: relative;
        }
        .testimonial-card::before {
            content: '"';
            position: absolute;
            font-size: 6rem;
            color: rgba(44, 107, 179, 0.1);
            top: -20px;
            left: 15px;
            font-family: Georgia, serif;
        }
        .client-info {
            display: flex;
            align-items: center;
            margin-top: 1.5rem;
        }
        .client-img {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            object-fit: cover;
            margin-right: 1rem;
            border: 3px solid #f0f5ff;
        }
        .friendlink {
            background-color: #f8f9fa;
            padding: 4rem 0;
        }
        .flink {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 1rem 1.5rem;
            margin: 0.5rem;
            background: white;
            border-radius: 8px;
            color: var(--text-color);
            font-weight: 600;
            text-decoration: none;
            box-shadow: var(--shadow);
            transition: var(--transition);
            border: 1px solid #eee;
            min-width: 150px;
        }
        .flink:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
            color: var(--primary-color);
            border-color: var(--primary-color);
        }
        .flink i {
            margin-right: 8px;
            font-size: 1.2rem;
        }
        footer {
            background-color: var(--dark-color);
            color: rgba(255, 255, 255, 0.85);
            padding: 4rem 0 2rem;
        }
        .footer-logo {
            font-size: 2rem;
            font-weight: 800;
            color: white;
            margin-bottom: 1.5rem;
            display: inline-block;
        }
        .footer-links h5 {
            color: white;
            margin-bottom: 1.5rem;
            font-size: 1.2rem;
        }
        .footer-links ul {
            list-style: none;
            padding: 0;
        }
        .footer-links li {
            margin-bottom: 0.8rem;
        }
        .footer-links a {
            color: rgba(255, 255, 255, 0.75);
            text-decoration: none;
            transition: var(--transition);
        }
        .footer-links a:hover {
            color: var(--secondary-color);
            padding-left: 5px;
        }
        .contact-info li {
            display: flex;
            align-items: flex-start;
            margin-bottom: 1.2rem;
        }
        .contact-info i {
            color: var(--secondary-color);
            margin-right: 12px;
            margin-top: 5px;
            font-size: 1.1rem;
        }
        .copyright {
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            padding-top: 2rem;
            margin-top: 3rem;
            text-align: center;
            font-size: 0.9rem;
            color: rgba(255, 255, 255, 0.6);
        }
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 50px;
            height: 50px;
            background-color: var(--primary-color);
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.2rem;
            text-decoration: none;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
            z-index: 1000;
            transition: var(--transition);
            opacity: 0;
            visibility: hidden;
        }
        .back-to-top.active {
            opacity: 1;
            visibility: visible;
        }
        .back-to-top:hover {
            background-color: #1a5bb8;
            transform: translateY(-3px);
        }
        @media (max-width: 768px) {
            .hero-title {
                font-size: 2.5rem;
            }
            .hero-subtitle {
                font-size: 1.1rem;
            }
            .section-title {
                font-size: 2rem;
            }
            .flink {
                min-width: 130px;
                padding: 0.8rem 1rem;
                font-size: 0.9rem;
            }
        }
        @media (max-width: 576px) {
            .hero-section {
                padding: 6rem 0 4rem;
            }
            .hero-title {
                font-size: 2rem;
            }
            .stat-number {
                font-size: 2.5rem;
            }
        }