/* 主内容区域 */
        .main {
            width: 100%;
            max-width: 1200px;
            margin: 120px auto 20px;
            padding: 0 15px;
        }
        
        .section-title {
            font-size: 24px;
            margin-bottom: 20px;
            padding-bottom: 15px;
            border-bottom: 2px solid #1a4b8c;
            color: #1a4b8c;
            position: relative;
            display: inline-block;
        }
        
        .section-title::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            width: 50px;
            height: 2px;
            background-color: #ffd700;
        }

        .category-tabs {
            display: flex;
            justify-content: center;
            margin-bottom: 30px;
            flex-wrap: wrap;
        }

        .category-tab {
            padding: 10px 20px;
            margin: 0 10px 10px;
            background-color: #f0f4f8;
            border-radius: 30px;
            font-size: 16px;
            cursor: pointer;
            transition: all 0.3s;
        }

        .category-tab.active {
            background-color: #1a4b8c;
            color: white;
        }

        .course-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
            gap: 25px;
        }

        .course-card {
            background-color: white;
            border-radius: 8px;
            overflow: hidden;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
            transition: all 0.3s;
            position: relative;
        }

        .course-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
        }

        .course-image {
            height: 180px;
            overflow: hidden;
            position: relative;
        }

        .course-image img {
            width: 100%;
            height: 100%;
            object-fit: cover;
            transition: all 0.5s;
        }

        .course-card:hover .course-image img {
            transform: scale(1.1);
        }

        .course-type {
            position: absolute;
            top: 15px;
            right: 15px;
            padding: 5px 12px;
            border-radius: 15px;
            font-size: 12px;
            font-weight: bold;
        }

        .video-type {
            background-color: #ff4757;
            color: white;
        }

        .audio-type {
            background-color: #00b894;
            color: white;
        }

        .text-image-type {
            background-color: #5352ed;
            color: white;
        }

        .play-icon {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            width: 50px;
            height: 50px;
            background-color: rgba(0, 0, 0, 0.6);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-size: 20px;
            opacity: 0;
            transition: all 0.3s;
        }

        .course-card:hover .play-icon {
            opacity: 1;
        }

        .course-info {
            padding: 20px;
        }

        .course-title {
            font-size: 18px;
            margin-bottom: 10px;
            color: #1a4b8c;
            font-weight: 600;
            display: -webkit-box;
            -webkit-box-orient: vertical;
            -webkit-line-clamp: 2;
            overflow: hidden;
        }

        .course-instructor {
            display: flex;
            align-items: center;
            margin-bottom: 10px;
            font-size: 15px;
            color: #666;
            line-height: 1.6;
            display: -webkit-box;
            -webkit-box-orient: vertical;
            -webkit-line-clamp: 2;
            overflow: hidden;
        }

        .instructor-avatar {
            width: 30px;
            height: 30px;
            border-radius: 50%;
            margin-right: 10px;
        }

        .instructor-name {
            font-size: 14px;
            color: #666;
        }

        .course-meta {
            display: flex;
            justify-content: space-between;
            margin-top: 15px;
            font-size: 14px;
            color: #777;
        }

        .course-rating {
            display: flex;
            align-items: center;
        }

        .course-rating i {
            color: #ffd700;
            margin-right: 5px;
        }

        .course-participants i {
            margin-right: 5px;
        }

        .course-price {
            font-size: 18px;
            font-weight: 600;
            color: #ff4757;
        }

        .free-course {
            color: #00b894;
        }

        /* 课程详情页样式 */
        .course-detail {
            background-color: white;
            border-radius: 8px;
            padding: 30px;
            margin-bottom: 40px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
        }

        .course-header {
            display: flex;
            margin-bottom: 30px;
        }

        .course-thumbnail {
            width: 400px;
            height: 250px;
            border-radius: 8px;
            overflow: hidden;
            margin-right: 30px;
        }

        .course-thumbnail img {
            width: 100%;
            height: 100%;
            object-fit: cover;
        }

        .course-content {
            flex: 1;
        }

        .course-content h1 {
            font-size: 28px;
            margin-bottom: 15px;
            color: #1a4b8c;
        }

        .course-meta-detail {
            display: flex;
            margin-bottom: 20px;
        }

        .course-meta-item {
            display: flex;
            align-items: center;
            margin-right: 20px;
            font-size: 16px;
            color: #666;
        }

        .course-meta-item i {
            margin-right: 8px;
            color: #1a4b8c;
        }

        .course-description {
            margin-bottom: 25px;
            line-height: 1.8;
            color: #555;
        }

        .course-instructor-detail {
            display: flex;
            align-items: center;
            margin-bottom: 30px;
        }

        .instructor-avatar-large {
            width: 80px;
            height: 80px;
            border-radius: 50%;
            margin-right: 20px;
        }

        .instructor-info h3 {
            font-size: 20px;
            margin-bottom: 8px;
            color: #1a4b8c;
        }

        .instructor-info p {
            font-size: 15px;
            color: #666;
        }

        .course-chapters {
            margin-top: 40px;
        }

        .chapter-title {
            font-size: 22px;
            margin-bottom: 20px;
            color: #1a4b8c;
            padding-bottom: 10px;
            border-bottom: 1px solid #e9ecef;
        }

        .chapter-list {
            list-style: none;
        }

        .chapter-item {
            display: flex;
            justify-content: space-between;
            padding: 15px 0;
            border-bottom: 1px solid #f0f4f8;
            transition: all 0.3s;
        }

        .chapter-item:hover {
            background-color: #f9f9f9;
        }

        .chapter-info {
            display: flex;
            align-items: center;
        }

        .chapter-icon {
            margin-right: 15px;
            color: #1a4b8c;
        }

        .chapter-name {
            font-size: 16px;
        }

        .chapter-meta {
            font-size: 14px;
            color: #777;
        }

        .chapter-actions {
            display: flex;
            align-items: center;
        }

        .preview-btn {
            margin-right: 15px;
        }

        .preview-btn i,
        .download-btn i {
            cursor: pointer;
            color: #666;
            font-size: 18px;
        }

        .preview-btn i:hover {
            color: #ffd700;
        }

        .download-btn i:hover {
            color: #00b894;
        }

        .enroll-btn {
            display: inline-block;
            padding: 12px 25px;
            background-color: #1a4b8c;
            color: white;
            border-radius: 6px;
            font-size: 16px;
            text-decoration: none;
            margin-top: 15px;
            transition: all 0.3s;
            display: inline-flex;
            align-items: center;
        }

        .enroll-btn i {
            margin-right: 10px;
        }

        .enroll-btn:hover {
            background-color: #153a6d;
            box-shadow: 0 5px 15px rgba(26, 75, 140, 0.3);
        }
        

        .course-detail {
            background-color: white;
            border-radius: 8px;
            padding: 30px;
            margin-bottom: 40px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
        }

        .course-header {
            display: flex;
            margin-bottom: 30px;
        }

        .course-thumbnail {
            width: 400px;
            height: 250px;
            border-radius: 8px;
            overflow: hidden;
            margin-right: 30px;
        }

        .course-thumbnail img {
            width: 100%;
            height: 100%;
            object-fit: cover;
        }

        .course-content {
            flex: 1;
        }

        .course-content h1 {
            font-size: 28px;
            margin-bottom: 15px;
            color: #1a4b8c;
        }

        .course-meta-detail {
            display: flex;
            margin-bottom: 20px;
        }

        .course-meta-item {
            display: flex;
            align-items: center;
            margin-right: 20px;
            font-size: 16px;
            color: #666;
        }

        .course-meta-item i {
            margin-right: 8px;
            color: #1a4b8c;
        }

        .course-description {
            margin-bottom: 25px;
            line-height: 1.8;
            color: #555;
        }

        .course-instructor-detail {
            display: flex;
            align-items: center;
            margin-bottom: 30px;
        }

        .instructor-avatar-large {
            width: 80px;
            height: 80px;
            border-radius: 50%;
            margin-right: 20px;
        }

        .instructor-info h3 {
            font-size: 20px;
            margin-bottom: 8px;
            color: #1a4b8c;
        }

        .instructor-info p {
            font-size: 15px;
            color: #666;
        }

        .enroll-btn {
            display: inline-block;
            padding: 12px 25px;
            background-color: #1a4b8c;
            color: white;
            border-radius: 6px;
            font-size: 16px;
            text-decoration: none;
            margin-top: 15px;
            transition: all 0.3s;
            display: inline-flex;
            align-items: center;
        }

        .enroll-btn i {
            margin-right: 10px;
        }

        .enroll-btn:hover {
            background-color: #153a6d;
            box-shadow: 0 5px 15px rgba(26, 75, 140, 0.3);
        }

        .course-content-image {
            width: 100%;
            border-radius: 8px;
            margin: 20px 0;
            max-height: 400px;
            object-fit: cover;
        }

        .content-section {
            margin-bottom: 30px;
        }

        .content-section h3 {
            font-size: 22px;
            color: #1a4b8c;
            margin-bottom: 15px;
            padding-bottom: 10px;
            border-bottom: 1px solid #f0f4f8;
        }

        .content-section p {
            margin-bottom: 15px;
            line-height: 1.8;
        }

        .chapter-title {
            font-size: 22px;
            margin-bottom: 20px;
            color: #1a4b8c;
            padding-bottom: 10px;
            border-bottom: 1px solid #e9ecef;
        }

        .chapter-list {
            list-style: none;
        }

        .chapter-item {
            display: flex;
            justify-content: space-between;
            padding: 15px 0;
            border-bottom: 1px solid #f0f4f8;
            transition: all 0.3s;
        }

        .chapter-item:hover {
            background-color: #f9f9f9;
        }

        .chapter-info {
            display: flex;
            align-items: center;
        }

        .chapter-icon {
            margin-right: 15px;
            color: #1a4b8c;
        }

        .chapter-name {
            font-size: 16px;
        }

        .chapter-meta {
            font-size: 14px;
            color: #777;
        }

        .chapter-actions {
            display: flex;
            align-items: center;
        }

        .preview-btn {
            margin-right: 15px;
        }

        .preview-btn i,
        .download-btn i {
            cursor: pointer;
            color: #666;
            font-size: 18px;
        }

        .preview-btn i:hover {
            color: #ffd700;
        }

        .download-btn i:hover {
            color: #00b894;
        }

        .related-courses {
            margin-top: 50px;
        }

        .related-courses h3 {
            font-size: 22px;
            margin-bottom: 20px;
            color: #1a4b8c;
        }

        .related-course-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
            gap: 25px;
        }

        .related-course-card {
            background-color: white;
            border-radius: 8px;
            overflow: hidden;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
            transition: all 0.3s;
            position: relative;
        }

        .related-course-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
        }

        .related-course-image {
            height: 180px;
            overflow: hidden;
            position: relative;
        }

        .related-course-image img {
            width: 100%;
            height: 100%;
            object-fit: cover;
            transition: all 0.5s;
        }

        .related-course-card:hover .related-course-image img {
            transform: scale(1.1);
        }

        .related-course-info {
            padding: 20px;
        }

        .related-course-title {
            font-size: 18px;
            margin-bottom: 10px;
            color: #1a4b8c;
        }

        .related-course-meta {
            display: flex;
            justify-content: space-between;
            margin-top: 15px;
            font-size: 14px;
            color: #777;
        }
        
        .related-services {
            background-color: white;
            border-radius: 8px;
            padding: 30px;
            margin-bottom: 30px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
        }
        
        .related-services h2 {
            font-size: 22px;
            margin-bottom: 20px;
            color: #1a4b8c;
            padding-bottom: 10px;
            border-bottom: 2px solid #f0f0f0;
        }
        
        .related-services-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 20px;
        }
        
        .related-service {
            display: flex;
            background-color: #f9f9f9;
            border-radius: 6px;
            overflow: hidden;
            transition: transform 0.3s ease;
        }
        
        .related-service:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
        }
        
        .related-service-image {
            flex: 0 0 100px;
        }
        
        .related-service-image img {
            width: 100%;
            height: 100%;
            object-fit: cover;
        }
        
        .related-service-content {
            flex: 1;
            padding: 15px;
        }
        
        .related-service-content h3 {
            font-size: 16px;
            margin-bottom: 10px;
            color: #1a4b8c;
        }
        
        .related-service-content p {
            font-size: 13px;
            color: #666;
            margin-bottom: 10px;
        }
        
        .related-service-link {
            display: inline-block;
            padding: 5px 10px;
            background-color: #1a4b8c;
            color: white;
            text-decoration: none;
            border-radius: 4px;
            font-size: 12px;
            transition: background-color 0.3s ease;
        }
        
        .related-service-link:hover {
            background-color: #0f3a75;
        }
        
        
        /* 视频播放器样式 */
        .video-modal {
            display: none;
            position: fixed;
            z-index: 2000;
            left: 0;
            top: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.8);
        }

        .video-content {
            position: relative;
            width: 80%;
            max-width: 800px;
            margin: 5% auto;
        }

        .video-close {
            position: absolute;
            z-index: 999;
            top: 10px;
            right: 20px;
            color: white;
            font-size: 28px;
            font-weight: bold;
            cursor: pointer;
        }

        .video-player {
            width: 100%;
            aspect-ratio: 16/9;
            border-radius: 8px;
        }
        
        /* 音频播放器样式 */
        .audio-player {
            width: 100%;
            margin: 20px 0;
            background-color: #fff;
            border-radius: 8px;
            padding: 15px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
        }

        .audio-player-controls {
            display: flex;
            align-items: center;
            margin-bottom: 10px;
        }

        .play-btn {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background-color: #1a4b8c;
            color: white;
            display: flex;
            justify-content: center;
            align-items: center;
            cursor: pointer;
            margin-right: 15px;
            transition: all 0.3s;
        }

        .play-btn:hover {
            background-color: #153a6d;
        }

        .play-btn i {
            font-size: 16px;
        }

        .audio-info {
            flex: 1;
        }

        .audio-title {
            font-size: 16px;
            font-weight: 600;
            margin-bottom: 5px;
            color: #333;
        }

        .audio-time {
            font-size: 14px;
            color: #777;
            display: flex;
            justify-content: space-between;
        }

        .audio-progress {
            height: 4px;
            background-color: #e9ecef;
            border-radius: 2px;
            margin-top: 10px;
            position: relative;
            cursor: pointer;
        }

        .audio-progress-bar {
            height: 100%;
            background-color: #1a4b8c;
            border-radius: 2px;
            width: 0;
        }

        .audio-volume {
            display: flex;
            align-items: center;
            margin-left: 15px;
        }

        .audio-volume i {
            margin-right: 8px;
            color: #555;
        }

        .audio-volume-slider {
            width: 80px;
            height: 4px;
            background-color: #e9ecef;
            border-radius: 2px;
            position: relative;
            cursor: pointer;
        }

        .audio-volume-level {
            height: 100%;
            background-color: #1a4b8c;
            border-radius: 2px;
            width: 70%;
        }
        
        /* 音频播放器样式 */
        .audio-player {
            width: 100%;
            margin: 20px 0;
        }
        .audio-player-controls {
            display: flex;
            align-items: center;
            gap: 15px;
            padding: 10px;
            background-color: #f5f5f5;
            border-radius: 5px;
        }
        .play-btn, .fast-forward-btn {
            cursor: pointer;
            font-size: 16px;
        }
        .audio-info {
            flex-grow: 1;
        }
        .audio-title {
            font-weight: bold;
            margin-bottom: 5px;
        }
        .audio-time {
            display: flex;
            align-items: center;
            gap: 5px;
            font-size: 12px;
            color: #666;
        }
        .audio-volume {
            width: 60px;
            display: flex;
            align-items: center;
            gap: 5px;
            cursor: pointer;
        }
        .audio-volume-slider {
            flex-grow: 1;
            height: 5px;
            background-color: #ccc;
            border-radius: 5px;
            position: relative;
        }
        .audio-volume-level {
            height: 100%;
            background-color: #3498db;
            border-radius: 5px;
            width: 70%; /* 默认音量 */
        }
        .audio-progress {
            width: 100%;
            height: 5px;
            background-color: #ccc;
            border-radius: 5px;
            margin-top: 10px;
            cursor: pointer;
            position: relative;
        }
        .audio-progress-bar {
            height: 100%;
            background-color: #3498db;
            border-radius: 5px;
            width: 0%;
        }

        @media (max-width: 768px) {
            .audio-player-controls {
                flex-direction: column;
                align-items: flex-start;
            }

            .audio-info {
                width: 100%;
                margin-top: 10px;
            }

            .audio-volume {
                margin-top: 10px;
                margin-left: 0;
                width: 100%;
            }
        }

        /* 针对不同课程类型的样式 */
        #videoCourse .preview-btn i {
            display: block;
        }

        #audioCourse .preview-btn i {
            display: block;
        }

        #textImageCourse .download-btn i {
            display: block;
        }