/* CSS 样式保持不变 */
        :root {
            --primary: #0699cd;
            --primary-dark: #1e93af;
            --secondary: #f8fafc;
            --text-main: #1e293b;
            --text-light: #64748b;
            --white: #ffffff;
            --border: #e2e8f0;
            --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
            --radius: 12px;
            --container-width: 1200px;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Inter', system-ui, -apple-system, sans-serif;
            color: var(--text-main);
            line-height: 1.6;
            background-color: var(--secondary);
        }

        a {
            text-decoration: none;
            color: inherit;
            transition: 0.2s;
        }

        ul {
            list-style: none;
        }

        img {
            max-width: 100%;
            display: block;
        }

        .container {
            max-width: var(--container-width);
            margin: 0 auto;
            padding: 0 20px;
        }

        section {
            padding: 60px 0;
        }

        .section-title {
            font-size: 2rem;
            font-weight: 700;
            text-align: center;
            margin-bottom: 40px;
            color: var(--text-main);
        }

        /* Header */
        header {
            background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
            color: var(--white);
            padding: 80px 0 100px 0;
            /* 底部增加padding给统计条留空间 */
            text-align: center;
        }

        header h1 {
            font-size: 3rem;
            margin-bottom: 16px;
            letter-spacing: -0.5px;
        }

        header p {
            font-size: 1.25rem;
            opacity: 0.9;
            max-width: 700px;
            margin: 0 auto;
        }

        /* Statistics */
        #statistics {
            background: var(--white);
            padding: 30px 0;
            border-bottom: 1px solid var(--border);
            margin-top: -50px;
            /* 上移重叠效果 */
            position: relative;
            z-index: 10;
            border-radius: var(--radius);
            box-shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1);
            max-width: 1000px;
            margin-left: auto;
            margin-right: auto;
        }

        #statistics .stats-list {
            display: flex;
            justify-content: space-around;
            flex-wrap: wrap;
            gap: 20px;
        }

        #statistics li {
            text-align: center;
            font-size: 1rem;
            color: var(--text-light);
        }

        #statistics li strong {
            display: block;
            font-size: 1.8rem;
            color: var(--primary);
            font-weight: 700;
            margin-bottom: 4px;
        }

        @media (max-width: 768px) {
            #statistics .stats-list {
                flex-wrap: nowrap;
                justify-content: space-between;
                padding: 0 10px;
            }

            #statistics li {
                font-size: 0.8rem;
            }

            #statistics li strong {
                font-size: 1.2rem;
            }
        }

        /* Grid Layout */
        .grid-2 {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 60px;
            align-items: center;
        }

        #audience h2,
        #advantages h2 {
            font-size: 1.5rem;
            margin-bottom: 20px;
            color: var(--text-main);
        }

        #audience ul li {
            position: relative;
            padding-left: 30px;
            margin-bottom: 16px;
            font-size: 1.1rem;
        }

        #audience ul li::before {
            content: "✓";
            position: absolute;
            left: 0;
            top: 2px;
            color: var(--primary);
            font-weight: bold;
        }

        /* Teacher Cards */
        #teachers ul {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
            gap: 30px;
        }

        .teacher-card {
            background: var(--white);
            border-radius: var(--radius);
            box-shadow: var(--shadow);
            overflow: hidden;
            border: 1px solid var(--border);
            transition: transform 0.2s, box-shadow 0.2s;
        }

        .teacher-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1);
        }

        .teacher-link {
            display: flex;
            flex-direction: column;
            height: 100%;
        }

        .teacher-header {
            padding: 24px;
            display: flex;
            align-items: center;
            gap: 16px;
        }

        .teacher-header img {
            width: 70px;
            height: 70px;
            border-radius: 50%;
            object-fit: cover;
            border: 2px solid var(--secondary);
        }

        .teacher-info h3 {
            font-size: 1.2rem;
            font-weight: 700;
            margin-bottom: 4px;
        }

        .teacher-info p {
            color: var(--primary);
            font-size: 0.9rem;
            font-weight: 500;
        }

        .teacher-desc {
            padding: 0 24px 20px 24px;
            font-size: 0.95rem;
            color: var(--text-light);
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }

        .teacher-footer {
            padding: 16px 24px;
            background: #f8fafc;
            border-top: 1px solid var(--border);
            margin-top: auto;
            font-size: 0.85rem;
            color: var(--text-light);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .tag {
            background: #dbeafe;
            color: var(--primary-dark);
            padding: 2px 8px;
            border-radius: 4px;
            font-size: 0.75rem;
            font-weight: 600;
        }

        /* Course Cards - New Design */
        #courses ul {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: 20px;
            margin-top: 20px;
        }

        .course-card {
            background: var(--white);
            border-radius: var(--radius);
            box-shadow: var(--shadow);
            border: 1px solid var(--border);
            overflow: hidden;
            transition: transform 0.2s, box-shadow 0.2s;
            display: flex;
            flex-direction: column;
        }

        .course-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.08);
        }

        .course-link {
            display: flex;
            flex-direction: column;
            height: 100%;
            text-decoration: none;
            color: inherit;
        }

        .course-img-wrapper {
            width: 100%;
            padding-bottom: 56.25%;
            /* 16:9 Aspect Ratio */
            position: relative;
            background: #f1f5f9;
        }

        .course-img-wrapper img {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            object-fit: cover;
        }

        .course-content {
            padding: 20px;
            flex-grow: 1;
            display: flex;
            flex-direction: column;
        }

        .course-title {
            font-size: 1.15rem;
            font-weight: 700;
            margin-bottom: 8px;
            line-height: 1.4;
            color: var(--text-main);
            /* Truncate 2 lines */
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }

        .course-desc {
            font-size: 0.9rem;
            color: var(--text-light);
            margin-bottom: 16px;
            line-height: 1.5;
            /* Truncate 2 lines */
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }

        .course-meta {
            display: flex;
            justify-content: space-between;
            font-size: 0.85rem;
            color: #64748b;
            padding-top: 15px;
            margin-top: auto;
            border-top: 1px solid #f1f5f9;
        }

        .course-meta span {
            display: flex;
            align-items: center;
            gap: 4px;
        }

        .course-price-row {
            margin-top: 15px;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .course-price {
            font-size: 1.25rem;
            font-weight: 700;
            color: var(--primary);
        }

        .course-btn {
            font-size: 0.85rem;
            font-weight: 600;
            color: var(--primary);
        }

        /* Reviews */
        .review-card {
            background: var(--white);
            padding: 30px;
            border-radius: var(--radius);
            border: 1px solid var(--border);
            box-shadow: var(--shadow);
        }

        .review-text {
            font-style: italic;
            font-size: 1rem;
            color: var(--text-main);
            margin-bottom: 20px;
        }

        .review-author {
            display: flex;
            align-items: center;
            gap: 10px;
            font-weight: 600;
            color: var(--text-main);
        }

        .review-author span {
            color: var(--text-light);
            font-weight: 400;
            font-size: 0.9rem;
        }

        /* CTA */
        #cta {
            text-align: center;
            background: var(--primary-dark);
            color: var(--white);
            padding: 100px 0;
            background-image: radial-gradient(circle at center, #2563eb 0%, #1e40af 100%);
        }

        .btn-cta {
            background: var(--white);
            color: var(--primary);
            padding: 18px 48px;
            font-size: 1.2rem;
            border-radius: 50px;
            font-weight: 700;
            display: inline-block;
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
        }

        /* Footer */
        footer {
            background: #0f172a;
            color: #94a3b8;
            padding: 60px 0;
            text-align: center;
        }

        footer a {
            color: #cbd5e1;
            font-size: 0.9em;
        }
        footer a:hover{
            color: #dde3e9;
            text-decoration: underline;

        }

        @media (max-width: 768px) {
            .grid-2 {
                grid-template-columns: 1fr;
                gap: 40px;
            }

            header h1 {
                font-size: 2.2rem;
            }

            #statistics {
                margin-top: 0;
                border-radius: 0;
            }
        }

        /* Header Wrapper Styles */
        .HeaderWrapper {
            background: #fff;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
            position: sticky;
            top: 0;
            z-index: 1000;
            width: 100%;
        }

        .header-inner {
            /* max-width: var(--container-width, 1200px); */
            margin: 0 auto;
            padding: 0 20px;
            height: 60px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 0.8rem;
        }

        .header-left {
            display: flex;
            align-items: center;
            gap: 40px;
        }

        .header-logo img {
            height: 40px;
            width: auto;
        }

        .header-nav {
            display: flex;
            gap: 25px;
            list-style: none;
            margin: 0;
            padding: 0;
            height: 40px;
            align-items: center;
        }

        .header-nav li {
            height: 40px;
            display: flex;
            align-items: center;
        }

        .header-nav a {
            font-weight: 600;
            color: #0699cd;
            /* font-size: 1rem; */
            position: relative;
            text-decoration: none;
            display: inline-flex;
            align-items: center;
            height: 100%;
            padding: 0 5px;
        }

        .header-nav a::after {
            content: '';
            position: absolute;
            width: 100%;
            height: 2px;
            bottom: 0;
            left: 0;
            background-color: #0699cd;
            transform: scaleX(0);
            transform-origin: center;
            transition: transform 0.3s ease-in-out;
        }

        .header-nav a:hover::after {
            transform: scaleX(1);
        }

        .header-nav a:hover {
            color: #0699cd;
        }

        .header-right {
            display: flex;
            align-items: center;
            gap: 30px;
        }

        .header-actions {
            display: flex;
            align-items: center;
            gap: 25px;
        }

        .lang-selector {
            display: flex;
            align-items: center;
            background: #f2f7fd;
            border-radius: 8px;
            padding: 0 8px;
        }

        .lang-selector img {
            width: 20px;
            margin-right: 5px;
        }

        .lang-selector select {
            border: none;
            background: transparent;
            font-size: 0.9rem;
            color: var(--text-main);
            padding: 5px;
            cursor: pointer;
        }

        .lang-selector select:focus {
            outline: none;
            box-shadow: none !important;
        }

        .btn-text {
            font-weight: 600;
            color: #0699cd;
            position: relative;
            text-decoration: none;
            display: inline-flex;
            align-items: center;
            height: 40px;
            padding: 0 5px;
        }

        .btn-text::after {
            content: '';
            position: absolute;
            width: 100%;
            height: 2px;
            bottom: 0;
            left: 0;
            background-color: #0699cd;
            transform: scaleX(0);
            transform-origin: center;
            transition: transform 0.3s ease-in-out;
        }

        .btn-text:hover::after {
            transform: scaleX(1);
        }

        .btn-text:hover {
            color: #0699cd;
            text-decoration: none;
        }

        .btn-primary {
            background-color: #0699cd;
            color: white;
            border: none;
            padding: 8px 20px;
            border-radius: 20px;
            font-weight: 700;
            cursor: pointer;
            transition: background 0.2s;
        }

        .btn-primary:hover {
            background-color: #0588b6;
        }

        /* Mobile */
        .mobile-show {
            display: none;
        }

        .mobile-hide {
            display: flex;
        }

        @media (max-width: 900px) {
            .mobile-hide {
                display: none !important;
            }

            .mobile-show {
                display: block !important;
            }

            .header-nav {
                display: none;
            }
        }

        .footerItem {
            text-align: left;
        }

        .flex {
            display: -webkit-box;
            display: -webkit-flex;
            display: -ms-flexbox;
            display: flex;
        }

        .flex-direction-row {
            -webkit-box-orient: horizontal;
            /* -webkit-box-direction: normal; */
            /* -webkit-flex-direction: row; */
            -ms-flex-direction: row;
            flex-direction: row;
        }

        .flex-2 {
            -webkit-box-flex: 2;
            -webkit-flex: 2;
            -ms-flex: 2;
            flex: 2;
        }

        .flex-1 {
            -webkit-box-flex: 1;
            -webkit-flex: 1;
            -ms-flex: 1;
            flex: 1;
        }

        .flex-direction-column {
            /* -webkit-box-orient: vertical; */
            /* -webkit-box-direction: normal; */
            -webkit-flex-direction: column;
            -ms-flex-direction: column;
            flex-direction: column;
        }

        #MainApp {
            display: block;
        }