<style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: "Microsoft YaHei", sans-serif;
        }

        /* 页面布局 */
        body {
            display: flex;
            flex-direction: column;
            min-height: 100vh;
            background-color: #f5f7fa;
        }

        /* 一级导航栏样式 */
        .navbar {
            background-color: #2c3e50;
            padding: 0 20px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }

        .nav-list {
            display: flex;
            list-style: none;
            overflow-x: auto;
            scrollbar-width: none; /* 隐藏滚动条 */
        }

        .nav-list::-webkit-scrollbar {
            display: none;
        }

        .nav-item {
            padding: 0;
        }

        .nav-link {
            display: block;
            color: white;
            text-decoration: none;
            padding: 16px 20px;
            font-size: 16px;
            transition: background-color 0.3s;
            white-space: nowrap;
        }

        .nav-link:hover, .nav-link.active {
            background-color: #34495e;
            color: #3498db;
        }

        /* 主体内容区 */
        .container {
            display: flex;
            flex: 1;
            padding: 20px;
            gap: 20px;
        }

        /* 二级侧边栏样式 */
        .sidebar {
            width: 260px;
            background-color: white;
            border-radius: 8px;
            box-shadow: 0 2px 10px rgba(0,0,0,0.05);
            padding: 20px;
            height: fit-content;
        }

        .sidebar-title {
            font-size: 18px;
            color: #2c3e50;
            margin-bottom: 15px;
            padding-bottom: 10px;
            border-bottom: 2px solid #3498db;
        }

        .major-list {
            list-style: none;
        }

        .major-item {
            margin-bottom: 10px;
        }

        .major-link {
            color: #34495e;
            text-decoration: none;
            font-size: 15px;
            padding: 8px 10px;
            display: block;
            border-radius: 4px;
            transition: background-color 0.2s;
        }

        .major-link:hover, .major-link.active {
            background-color: #e8f4fd;
            color: #3498db;
            font-weight: 500;
        }

        /* 内容展示区 */
        .content {
            flex: 1;
            background-color: white;
            border-radius: 8px;
            box-shadow: 0 2px 10px rgba(0,0,0,0.05);
            padding: 30px;
            min-height: 600px;
        }

        .content-title {
            font-size: 24px;
            color: #2c3e50;
            margin-bottom: 20px;
        }

        .content-desc {
            color: #666;
            line-height: 1.8;
            font-size: 16px;
        }

        .content-desc h4 {
            color: #2c3e50;
            margin: 15px 0 8px 0;
            font-size: 17px;
        }

        .content-desc .tag {
            display: inline-block;
            background-color: #e8f4fd;
            color: #3498db;
            padding: 2px 8px;
            border-radius: 4px;
            font-size: 14px;
            margin-right: 5px;
            margin-bottom: 5px;
        }

        /* 课程和书籍样式 */
        .course-section, .book-section {
            margin: 25px 0;
        }

        .section-title {
            font-size: 20px;
            color: #2c3e50;
            margin-bottom: 15px;
            padding-bottom: 8px;
            border-bottom: 1px solid #e8f4fd;
        }

        /* 区分公共课/专业课样式 */
        .public-course-list {
            border-left: 3px solid #2ecc71; /* 绿色标识公共课 */
        }
        .professional-course-list {
            border-left: 3px solid #3498db; /* 蓝色标识专业课 */
        }

        .course-list, .book-list {
            list-style: none;
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 12px;
        }

        .course-item, .book-item {
            background-color: #f8fbff;
            padding: 12px 15px;
            border-radius: 6px;
        }

        .book-item .author {
            font-size: 14px;
            color: #999;
            margin-top: 5px;
        }

        /* 返回大类按钮 */
        .back-btn {
            display: inline-block;
            background-color: #3498db;
            color: white;
            padding: 8px 15px;
            border-radius: 4px;
            text-decoration: none;
            font-size: 14px;
            margin-bottom: 20px;
            transition: background-color 0.2s;
        }

        .back-btn:hover {
            background-color: #2980b9;
        }

        /* 响应式适配 */
        @media (max-width: 768px) {
            .container {
                flex-direction: column;
            }
            .sidebar {
                width: 100%;
            }
            .course-list, .book-list {
                grid-template-columns: 1fr;
            }
        }
        /* 书籍链接样式 */
        .book-links {
            margin-top: 8px;
            display: flex;
            gap: 10px;
        }

        .book-link {
            display: inline-block;
            padding: 4px 12px;
            border-radius: 4px;
            font-size: 13px;
            text-decoration: none;
            transition: all 0.2s;
        }

        .read-link {
            background-color: #e8f4fd;
            color: #3498db;
            border: 1px solid #3498db;
        }

        .read-link:hover {
            background-color: #3498db;
            color: white;
        }

        .buy-link {
            background-color: #f0f9eb;
            color: #67c23a;
            border: 1px solid #67c23a;
        }

        .buy-link:hover {
            background-color: #67c23a;
            color: white;
        }

        .book-title {
            font-weight: 500;
            color: #2c3e50;
            margin-bottom: 5px;
        }

        /* B站视频样式 */
        .bilibili-course {
            display: flex;
            flex-direction: column;
            gap: 10px;
            padding: 15px !important;
        }

        .bilibili-link {
            text-decoration: none;
            color: inherit;
            display: block;
            overflow: hidden;
            border-radius: 8px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.1);
            transition: transform 0.3s, box-shadow 0.3s;
        }

        .bilibili-link:hover {
            transform: translateY(-3px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.15);
        }

        .bilibili-thumbnail {
            position: relative;
            width: 100%;
            height: 180px;
            overflow: hidden;
            background-color: #f4f4f4;
        }

        .bilibili-thumbnail img {
            width: 100%;
            height: 100%;
            object-fit: cover;
        }

        .bilibili-play-icon {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            width: 60px;
            height: 60px;
            background: rgba(0, 161, 214, 0.85);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            opacity: 0.9;
            transition: opacity 0.3s, transform 0.3s;
        }

        .bilibili-link:hover .bilibili-play-icon {
            opacity: 1;
            transform: translate(-50%, -50%) scale(1.1);
        }

        .bilibili-title {
            padding: 12px 15px;
            background: white;
            font-size: 14px;
            line-height: 1.4;
            color: #333;
            border-top: 1px solid #eee;
            max-height: 60px;
            overflow: hidden;
            text-overflow: ellipsis;
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
        }

        .course-name {
            font-weight: 600;
            color: #2c3e50;
            font-size: 15px;
            margin-bottom: 5px;
        }

        /* 调整课程列表布局 */
        .course-list {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 20px;
            list-style: none;
        }

        .course-item {
            background-color: #f8fbff;
            padding: 12px 15px;
            border-radius: 6px;
            border-left: 3px solid #2ecc71;
        }

        .course-item.professional-course-list {
            border-left: 3px solid #3498db;
        }

        .course-item.bilibili-course {
            border-left: 3px solid #f25d8e; /* B站粉色 */
        }
/* 关于页面样式 */
.about-content {
    max-width: 1000px;
    margin: 0 auto;
}

.about-header {
    text-align: center;
    padding: 30px 0 40px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    margin-bottom: 40px;
    color: white;
    position: relative;
    overflow: hidden;
}

.about-header::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 1px, transparent 1px);
    background-size: 20px 20px;
    animation: float 20s linear infinite;
    pointer-events: none;
}

@keyframes float {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.university-title {
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 10px;
    letter-spacing: 2px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.university-subtitle {
    font-size: 20px;
    opacity: 0.95;
    margin-bottom: 15px;
}

.university-badge {
    display: inline-block;
    background: rgba(255,255,255,0.2);
    padding: 8px 20px;
    border-radius: 25px;
    font-size: 14px;
    backdrop-filter: blur(10px);
}

.about-section {
    margin: 40px 0;
    padding: 30px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    position: relative;
}

.about-section h3 {
    font-size: 24px;
    color: #2c3e50;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.section-icon {
    font-size: 28px;
    margin-right: 10px;
}

.about-list {
    list-style: none;
    margin: 20px 0;
    padding: 0;
}

.about-list li {
    padding: 10px 0;
    border-bottom: 1px solid #eee;
    display: flex;
    align-items: center;
    gap: 10px;
}

.about-list li:last-child {
    border-bottom: none;
}

.check {
    color: #2ecc71;
    font-weight: bold;
    font-size: 18px;
}

/* 特色网格 */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 25px;
    margin-top: 25px;
}

.feature-card {
    background: linear-gradient(145deg, #f8fbff, #e8f4fd);
    padding: 25px;
    border-radius: 12px;
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
    border: 1px solid rgba(52, 152, 219, 0.2);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(52, 152, 219, 0.15);
}

.feature-icon {
    font-size: 36px;
    margin-bottom: 15px;
}

.feature-card h4 {
    font-size: 18px;
    color: #2c3e50;
    margin-bottom: 10px;
}

.feature-card p {
    color: #666;
    font-size: 14px;
    line-height: 1.5;
}

/* 校区标签 */
.campus-tabs {
    display: flex;
    gap: 10px;
    margin: 20px 0 30px;
    flex-wrap: wrap;
}

.campus-tab {
    padding: 12px 24px;
    background: #f8f9fa;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 15px;
    cursor: pointer;
    transition: all 0.3s;
    flex: 1;
    min-width: 140px;
    text-align: center;
}

.campus-tab:hover {
    background: #e9ecef;
    border-color: #dee2e6;
}

.campus-tab.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-color: #667eea;
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.campus-content {
    display: none;
    padding: 20px;
    background: #f8fbff;
    border-radius: 10px;
    border-left: 4px solid #667eea;
    margin-bottom: 20px;
}

.campus-content.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 认证网格 */
.certificate-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 20px;
    margin-top: 25px;
}

.certificate-item {
    background: white;
    padding: 20px;
    border-radius: 10px;
    text-align: center;
    border: 1px solid #e8f4fd;
    transition: transform 0.3s;
}

.certificate-item:hover {
    transform: translateY(-5px);
    border-color: #3498db;
}

.badge-icon {
    font-size: 32px;
    margin-bottom: 10px;
}

/* 引用样式 */
.about-quote {
    margin: 40px 0;
    padding: 30px;
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    border-radius: 12px;
    color: white;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.about-quote::before {
    content: '"';
    font-size: 120px;
    position: absolute;
    top: -20px;
    left: 20px;
    opacity: 0.3;
    font-family: serif;
}

.about-quote blockquote {
    font-size: 24px;
    font-style: italic;
    margin: 0;
    line-height: 1.6;
}

.about-quote footer {
    margin-top: 15px;
    font-size: 16px;
    opacity: 0.9;
}

/* 页脚样式 */
.about-footer {
    text-align: center;
    padding: 40px 0 20px;
    margin-top: 40px;
    border-top: 2px solid #e8f4fd;
}

.join-call {
    font-size: 20px;
    color: #2c3e50;
    margin-bottom: 25px;
    font-weight: 500;
}

.action-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.action-btn {
    padding: 14px 32px;
    border-radius: 30px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    border: none;
    min-width: 180px;
}

.action-btn.primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.action-btn.secondary {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(79, 172, 254, 0.3);
}

.action-btn.outline {
    background: transparent;
    color: #667eea;
    border: 2px solid #667eea;
}

.action-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 7px 20px rgba(0,0,0,0.15);
}

.contact-info {
    color: #666;
    font-size: 14px;
    line-height: 1.8;
    margin-top: 30px;
}

.contact-info p {
    margin: 5px 0;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .university-title {
        font-size: 36px;
    }
    
    .features-grid,
    .certificate-grid {
        grid-template-columns: 1fr;
    }
    
    .action-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .action-btn {
        width: 100%;
        max-width: 300px;
    }
    
    .campus-tabs {
        flex-direction: column;
    }
}
 
  

/* 最简单返回顶部按钮样式 */
.back-to-top-btn {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    display: none;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.back-to-top-btn:hover {
    background-color: #2980b9;
}

.back-to-top-btn:active {
    transform: scale(0.95);
}

/* 移动端适配基础样式 */
* {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent; /* 移除移动端点击高亮 */
}

body {
    margin: 0;
    padding: 0;
    min-height: 100vh;
    overflow-x: hidden;
}

/* 移动端字体优化 */
@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    body {
        font-size: 16px;
        line-height: 1.6;
        -webkit-font-smoothing: antialiased;
        -moz-osx-font-smoothing: grayscale;
    }
}

/* 移动端触摸反馈优化 */
button, a, .nav-link, .major-link {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    user-select: none;
}

/* 主容器响应式布局 */
.container {
    display: flex;
    flex-direction: row;
    min-height: 100vh;
}

@media (max-width: 768px) {
    .container {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        max-height: 60vh;
        overflow-y: auto;
        position: relative;
        border-right: none;
        border-bottom: 1px solid #ddd;
        padding-bottom: 40px; /* 为移动菜单预留空间 */
    }
    
    .content {
        margin-left: 0 !important;
        width: 100%;
        padding: 15px;
        max-width: 100% !important;
    }
}

/* 一级导航栏移动端布局 */
.nav-list {
    display: flex;
    flex-wrap: nowrap;  /* 改为不换行 */
    flex-direction: row; /* 改为水平方向 */
    overflow-x: auto;   /* 允许横向滚动 */
    overflow-y: hidden;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch; /* iOS平滑滚动 */
    padding: 0;
    margin: 0;
    height: 60px; /* 固定高度 */
}

@media (max-width: 768px) {
    .nav-container {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        height: 60px;
        background: #2c3e50;
        z-index: 1000;
        box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    }
    
    .nav-list {
        display: flex;
        flex-direction: row;
        overflow-x: auto;
        overflow-y: hidden;
        -webkit-overflow-scrolling: touch;
        white-space: nowrap;
        height: 60px;
        padding: 0 10px;
    }
    
    .nav-item {
        flex: 0 0 auto; /* 不自动伸缩 */
        width: auto;
    }
    
    .nav-link {
        height: 60px;
        padding: 0 20px;
        display: flex;
        align-items: center;
        justify-content: center;
        white-space: nowrap;
    }
    
    /* 隐藏导航图标以节省空间 */
    .nav-icon {
        display: none;
    }
}

/* 侧边栏移动端样式 */
@media (max-width: 768px) {
    .sidebar {
        margin-top: 60px; /* 为固定导航栏留出空间 */
        width: 100%;
    }
    
    .sidebar-content {
        padding: 15px;
    }
    
    #sidebar-title {
        font-size: 20px;
        padding: 15px 0;
        text-align: center;
    }
    
    .major-list {
        max-height: 40vh;
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
    }
    
    .major-link {
        padding: 12px 15px;
        font-size: 16px;
        border-radius: 10px;
        margin-bottom: 8px;
    }
}

/* 内容区域移动端优化 */
@media (max-width: 768px) {
    #content-title {
        font-size: 22px;
        margin: 15px 0;
        padding: 15px;
        text-align: center;
        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        color: white;
        border-radius: 8px;
    }
    
    #content-desc {
        padding: 15px;
        line-height: 1.6;
    }
    
    /* 关于页面移动端优化 */
    .about-content {
        padding: 15px;
    }
    
    .about-header {
        padding: 25px 15px;
        border-radius: 8px;
        margin-bottom: 25px;
    }
    
    .university-title {
        font-size: 32px;
    }
    
    .university-subtitle {
        font-size: 16px;
    }
}

/* 课程列表移动端样式 */
@media (max-width: 768px) {
    .course-section {
        margin: 25px 0;
        padding: 15px;
        border-radius: 8px;
    }
    
    .section-title {
        font-size: 18px;
        margin-bottom: 15px;
        padding: 12px 0;
    }
    
    .course-list, .book-list {
        padding: 0;
    }
    
    .course-item, .book-item {
        padding: 15px;
        margin-bottom: 10px;
        border-radius: 8px;
    }
    
    .course-name {
        font-size: 16px;
        font-weight: 600;
        margin-bottom: 8px;
    }
    
    /* B站视频缩略图优化 */
    .bilibili-thumbnail {
        width: 100%;
        margin: 10px 0;
    }
    
    .bilibili-thumbnail img {
        width: 100%;
        height: auto;
        max-height: 200px;
        object-fit: cover;
    }
    
    .bilibili-title {
        font-size: 14px;
        line-height: 1.4;
    }
}

/* 书籍列表移动端样式 */
@media (max-width: 768px) {
    .book-item {
        padding: 12px;
    }
    
    .book-title {
        font-size: 16px;
        font-weight: 500;
        margin-bottom: 5px;
    }
    
    .author {
        font-size: 14px;
        color: #666;
        margin-bottom: 10px;
    }
    
    .book-links {
        display: flex;
        flex-direction: column;
        gap: 8px;
    }
    
    .book-link {
        padding: 8px 12px;
        text-align: center;
        border-radius: 6px;
        font-size: 14px;
    }
}

/* 返回顶部按钮移动端优化 */
@media (max-width: 768px) {
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 50px;
        height: 50px;
        font-size: 20px;
        box-shadow: 0 3px 8px rgba(0,0,0,0.2);
    }
    
    /* 防止移动端误触 */
    .back-to-top:active {
        transform: scale(0.95);
    }
}

/* 底部安全区域适配 */
@supports (padding-bottom: env(safe-area-inset-bottom)) {
    @media (max-width: 768px) {
        .container {
            padding-bottom: env(safe-area-inset-bottom);
        }
        
        .back-to-top {
            bottom: calc(20px + env(safe-area-inset-bottom));
        }
    }
}


    </style>