/* 全局基础样式重置 */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: "Microsoft Yahei", Arial, sans-serif;
        }
        body {
            background-color: #f5f7fa;
            color: #333;
        }

        /* 头部样式 */
        header {
            background-color: #fff;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
            padding: 0 5%;
            height: 80px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 999;
        }
        .logo img {
            max-height: 62px;
        }
        nav ul {
            display: flex;
            list-style: none;
            gap: 15px;
        }
        nav ul li a {
            text-decoration: none;
            color: #666;
            padding: 8px 15px;
            border-radius: 4px;
            transition: all 0.3s ease;
        }
        .nav-login-btn {
            background-color: #f0f4f8;
            color: #06b6d4 !important;
        }
        .nav-login-btn-highlight {
            background-color: #06b6d4 !important;
            color: #fff !important;
        }
        .nav-register-btn {
            background-color: #818cf8 !important;
            color: #fff !important;
        }
        nav ul li a:hover {
            color: #06b6d4;
        }

        /* 课程频道页核心样式 */
        .course-channel {
            padding: 3rem 5%;
            max-width: 1200px;
            margin: 100px auto 50px; /* 预留头部高度 */
            background: #ffffff;
            border-radius: 12px;
            box-shadow: 0 5px 20px rgba(6, 182, 212, 0.08);
        }

        /* 面包屑导航 */
        .breadcrumbs {
            font-size: 0.9rem;
            color: #64748b;
            margin-bottom: 1.5rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .breadcrumbs a {
            color: #06b6d4;
            text-decoration: none;
        }
        .breadcrumbs a:hover {
            text-decoration: underline;
        }
        .back-btn {
            padding: 0.4rem 1rem;
            background: #f8fafc;
            border: 1px solid rgba(6, 182, 212, 0.2);
            border-radius: 4px;
            color: #06b6d4;
            transition: all 0.3s ease;
            text-decoration: none;
        }
        .back-btn:hover {
            background: #06b6d4;
            color: #fff;
            text-decoration: none;
        }

        /* 课程头部信息 */
        .course-header {
            display: flex;
            gap: 2rem;
            margin-bottom: 2rem;
            padding-bottom: 2rem;
            border-bottom: 1px solid rgba(6, 182, 212, 0.1);
        }
        .course-cover {
            flex: 1;
            max-width: 300px;
            border-radius: 8px;
            overflow: hidden;
            box-shadow: 0 3px 10px rgba(6, 182, 212, 0.1);
        }
        .course-cover img {
            width: 100%;
            height: auto;
            object-fit: cover;
        }
        .course-info {
            flex: 2;
        }
        .course-title {
            font-size: 1.8rem;
            color: #1e293b;
            margin-bottom: 1.2rem;
            line-height: 1.3;
        }
        .course-meta {
            list-style: none;
            display: flex;
            flex-wrap: wrap;
            gap: 1rem 2rem;
            font-size: 0.95rem;
            color: #64748b;
        }
        .course-meta li {
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        .course-meta li i {
            color: #06b6d4;
        }

        /* 标签页导航 */
        .course-tabs {
            margin-top: 2rem;
        }
        .tab-nav {
            display: flex;
            gap: 0;
            border-bottom: 1px solid rgba(6, 182, 212, 0.2);
        }
        .tab-btn {
            padding: 1rem 2rem;
            background: #f8fafc;
            border: none;
            border-bottom: 3px solid transparent;
            font-size: 1.1rem;
            font-weight: 500;
            color: #64748b;
            cursor: pointer;
            transition: all 0.3s ease;
        }
        .tab-btn.active {
            border-bottom: 3px solid #06b6d4;
            background: #ffffff;
            color: #06b6d4;
        }
        .tab-btn:hover {
            color: #06b6d4;
        }

        /* 标签页内容 */
        .tab-content {
            padding: 2rem 0;
        }
        .tab-panel {
            display: none;
        }
        .tab-panel.active {
            display: block;
        }

        /* 课程介绍内容 */
        .intro-content {
            font-size: 1rem;
            color: #64748b;
            line-height: 1.8;
            padding: 0 1rem;
        }
        .intro-content p {
            margin-bottom: 1rem;
        }

        /* 课程目录内容 */
        .catalog-content {
            padding: 0 1rem;
        }
        .catalog-section {
            margin-bottom: 2rem;
        }
        .catalog-section h3 {
            font-size: 1.2rem;
            color: #1e293b;
            margin-bottom: 1rem;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        .catalog-section h3 i {
            color: #06b6d4;
        }
        .lesson-list {
            list-style: none;
            gap: 0.8rem;
            display: flex;
            flex-direction: column;
        }
        .lesson-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 1rem;
            background: #f8fafc;
            border-radius: 8px;
            border: 1px solid rgba(6, 182, 212, 0.1);
            color: #334155;
            text-decoration: none;
            transition: all 0.3s ease;
        }
        .lesson-item:hover {
            background: #ffffff;
            box-shadow: 0 3px 10px rgba(6, 182, 212, 0.1);
            border-color: #06b6d4;
        }
        .lesson-item i {
            color: #06b6d4;
            margin-right: 0.5rem;
        }
        .lesson-time {
            font-size: 0.85rem;
            color: #64748b;
            margin-right: 1rem;
        }
        .lesson-status i {
            color: #10b981;
        }

        /* 教师团队内容 */
        .teacher-content {
            display: flex;
            flex-wrap: wrap;
            gap: 2rem;
            padding: 0 1rem;
        }
        .teacher-card {
            display: flex;
            align-items: center;
            gap: 1.5rem;
            padding: 1.5rem;
            background: #f8fafc;
            border-radius: 8px;
            border: 1px solid rgba(6, 182, 212, 0.1);
            width: 100%;
            max-width: 500px;
        }
        .teacher-avatar {
            width: 80px;
            height: 80px;
            border-radius: 50%;
            overflow: hidden;
            border: 2px solid #06b6d4;
        }
        .teacher-avatar img {
            width: 100%;
            height: 100%;
            object-fit: cover;
        }
        .teacher-info h3 {
            font-size: 1.2rem;
            color: #1e293b;
            margin-bottom: 0.5rem;
        }
        .teacher-info p {
            font-size: 0.95rem;
            color: #64748b;
            line-height: 1.5;
        }

        /* 底部样式 */
        footer {
            text-align: center;
            padding: 2rem 0;
            color: #999;
            font-size: 0.9rem;
            border-top: 1px solid #eee;
        }
        footer a {
            color: #999;
            text-decoration: none;
        }
        footer a:hover {
            color: #06b6d4;
            text-decoration: underline;
        }

        /* 响应式适配 */
        @media (max-width: 768px) {
            header {
                height: auto;
                padding: 1rem 3%;
                flex-direction: column;
                gap: 1rem;
            }
            nav ul {
                flex-wrap: wrap;
                justify-content: center;
            }
            .course-channel {
                padding: 2rem 3%;
                margin: 180px auto 30px;
            }
            .course-header {
                flex-direction: column;
                gap: 1.5rem;
            }
            .course-cover {
                max-width: 100%;
            }
            .tab-btn {
                padding: 0.8rem 1.2rem;
                font-size: 1rem;
            }
            .lesson-item {
                flex-direction: column;
                align-items: flex-start;
                gap: 0.5rem;
            }
            .teacher-card {
                max-width: 100%;
            }
        }