/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部导航 */
.header {
    background-color: #fff;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo {
    font-size: 26px;
    font-weight: bold;
    color: #1a73e8;
}

.nav {
    display: flex;
    gap: 35px;
}

.nav a {
    text-decoration: none;
    color: #666;
    font-weight: 500;
    transition: color 0.3s;
    font-size: 15px;
}

.nav a:hover,
.nav a.active {
    color: #1a73e8;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    font-size: 15px;
}

.btn-primary {
    background-color: #1a73e8;
    color: #fff;
}

.btn-primary:hover {
    background-color: #1557b0;
}

.btn-secondary {
    background-color: #e8f0fe;
    color: #1a73e8;
}

.btn-secondary:hover {
    background-color: #d2e3fc;
}

.btn-outline {
    background-color: transparent;
    border: 2px solid #1a73e8;
    color: #1a73e8;
}

.btn-outline:hover {
    background-color: #1a73e8;
    color: #fff;
}

.btn-small {
    padding: 8px 18px;
    font-size: 14px;
}

.btn-large {
    padding: 15px 40px;
    font-size: 16px;
}

.btn-link {
    background: none;
    border: none;
    color: #1a73e8;
    cursor: pointer;
    text-decoration: underline;
    padding: 0;
}

/* 首页英雄区 */
.hero {
    background: linear-gradient(135deg, #0066cc 0%, #0099ff 100%);
    color: #fff;
    padding: 80px 0;
}

.hero-content {
    text-align: center;
}

.hero h1 {
    font-size: 48px;
    margin-bottom: 20px;
    font-weight: 700;
}

.subtitle {
    font-size: 20px;
    margin-bottom: 40px;
    opacity: 0.95;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
    margin: 40px 0;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 36px;
    font-weight: bold;
    margin-bottom: 8px;
}

.stat-label {
    font-size: 16px;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-top: 40px;
}

/* 分类卡片 */
.categories {
    padding: 80px 0;
    background-color: #fff;
}

.categories h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 50px;
    color: #333;
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 30px;
}

.category-card {
    background-color: #f8f9fa;
    padding: 40px 30px;
    border-radius: 12px;
    text-align: center;
    transition: all 0.3s;
    text-decoration: none;
    color: #333;
}

.category-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 24px rgba(0,0,0,0.1);
}

.category-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto 20px;
    color: #1a73e8;
}

.category-icon svg {
    width: 100%;
    height: 100%;
    stroke-width: 2;
}

.category-card h3 {
    font-size: 22px;
    margin-bottom: 10px;
}

.category-card p {
    color: #666;
    margin-bottom: 10px;
}

.course-tags {
    font-size: 14px;
    color: #999;
}

/* 精品课程 */
.featured-courses {
    padding: 80px 0;
    background-color: #f5f7fa;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
}

.section-header h2 {
    font-size: 36px;
    color: #333;
}

.view-all {
    color: #1a73e8;
    text-decoration: none;
    font-size: 16px;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
}

.course-card {
    background-color: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
    transition: all 0.3s;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
}

.course-image {
    width: 100%;
    height: 180px;
    background: linear-gradient(135deg, #1a73e8 0%, #4285f4 100%);
    position: relative;
}

.course-badge {
    position: absolute;
    top: 12px;
    left: 12px;
    background-color: rgba(255,255,255,0.95);
    color: #333;
    padding: 5px 12px;
    border-radius: 4px;
    font-size: 13px;
    font-weight: 500;
}

.course-badge.hot {
    background-color: #ff4757;
    color: #fff;
}

.course-badge.new {
    background-color: #1a73e8;
    color: #fff;
}

.course-level {
    position: absolute;
    top: 12px;
    right: 12px;
    background-color: rgba(0,0,0,0.6);
    color: #fff;
    padding: 5px 12px;
    border-radius: 4px;
    font-size: 13px;
}

.course-info {
    padding: 20px;
}

.course-info h3 {
    font-size: 18px;
    margin-bottom: 12px;
    color: #333;
    line-height: 1.4;
}

.course-desc {
    font-size: 14px;
    color: #666;
    line-height: 1.6;
    margin-bottom: 15px;
}

.course-meta {
    display: flex;
    gap: 15px;
    font-size: 14px;
    color: #999;
    margin-bottom: 12px;
}

.course-stats {
    display: flex;
    gap: 15px;
    font-size: 13px;
    color: #666;
    margin-bottom: 15px;
}

.rating {
    color: #ffa502;
}

.course-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.price {
    font-size: 16px;
    color: #1a73e8;
    font-weight: 600;
}

/* 学习路径 */
.learning-path {
    padding: 80px 0;
    background-color: #fff;
}

.learning-path h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 15px;
}

.section-desc {
    text-align: center;
    color: #666;
    margin-bottom: 50px;
    font-size: 18px;
}

.path-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.path-card {
    background-color: #f8f9fa;
    padding: 35px;
    border-radius: 12px;
    border: 2px solid #e9ecef;
}

.path-card h3 {
    font-size: 24px;
    margin-bottom: 25px;
    color: #333;
}

.path-steps {
    margin-bottom: 25px;
}

.step {
    padding: 12px 0;
    color: #666;
    border-left: 3px solid #1a73e8;
    padding-left: 15px;
    margin-bottom: 10px;
}

.path-info {
    color: #999;
    font-size: 14px;
    margin-bottom: 20px;
}

/* 名师团队 */
.teachers {
    padding: 80px 0;
    background-color: #f5f7fa;
}

.teachers h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 15px;
}

.teacher-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.teacher-card {
    background-color: #fff;
    padding: 35px 25px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.teacher-avatar {
    width: 80px;
    height: 80px;
    background-color: #1a73e8;
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    font-weight: bold;
    margin: 0 auto 20px;
}

.teacher-card h3 {
    font-size: 22px;
    margin-bottom: 8px;
}

.teacher-title {
    color: #666;
    font-size: 14px;
    margin-bottom: 15px;
}

.teacher-desc {
    color: #666;
    font-size: 14px;
    line-height: 1.6;
    margin-bottom: 15px;
}

.teacher-stats {
    display: flex;
    justify-content: center;
    gap: 20px;
    font-size: 13px;
    color: #999;
}

.text-center {
    text-align: center;
    margin-top: 20px;
}

/* 学员评价 */
.student-reviews {
    padding: 80px 0;
    background-color: #fff;
}

.student-reviews h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 50px;
}

.review-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.review-card {
    background-color: #f8f9fa;
    padding: 30px;
    border-radius: 12px;
}

.review-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 20px;
}

.reviewer-info {
    display: flex;
    gap: 15px;
}

.reviewer-avatar {
    width: 50px;
    height: 50px;
    background-color: #1a73e8;
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: bold;
}

.reviewer-info h4 {
    font-size: 16px;
    margin-bottom: 5px;
}

.reviewer-info p {
    font-size: 13px;
    color: #999;
}

.review-rating {
    color: #ffa502;
    font-size: 16px;
}

.review-content {
    color: #666;
    line-height: 1.8;
    margin-bottom: 15px;
}

.review-date {
    font-size: 13px;
    color: #999;
}

/* CTA区域 */
.cta-section {
    padding: 80px 0;
    background: linear-gradient(135deg, #0066cc 0%, #0099ff 100%);
    color: #fff;
    text-align: center;
}

.cta-section h2 {
    font-size: 42px;
    margin-bottom: 15px;
}

.cta-section p {
    font-size: 20px;
    margin-bottom: 40px;
    opacity: 0.95;
}

.cta-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
}

/* 页面头部 */
.page-header {
    background: linear-gradient(135deg, #0066cc 0%, #0099ff 100%);
    color: #fff;
    padding: 60px 0;
    text-align: center;
}

.page-header h1 {
    font-size: 42px;
    margin-bottom: 15px;
}

.page-header p {
    font-size: 18px;
    opacity: 0.95;
}

/* 页脚 */
.footer {
    background-color: #2c3e50;
    color: #fff;
    padding: 50px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 30px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 20px;
}

.footer-section p {
    color: #bdc3c7;
    margin-bottom: 10px;
    line-height: 1.8;
}

.footer-section a {
    display: block;
    color: #bdc3c7;
    text-decoration: none;
    margin-bottom: 10px;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: #fff;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid #34495e;
    color: #bdc3c7;
}

.footer-bottom a {
    color: #bdc3c7;
    text-decoration: none;
}

.footer-bottom a:hover {
    color: #fff;
}

/* 课程中心页面 */
.courses-section {
    padding: 60px 0;
}

.courses-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 30px;
}

.courses-sidebar {
    background-color: #fff;
    padding: 25px;
    border-radius: 12px;
    height: fit-content;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.filter-group {
    margin-bottom: 30px;
}

.filter-group h3 {
    font-size: 18px;
    margin-bottom: 15px;
    color: #333;
}

.filter-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.filter-list label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    color: #666;
    font-size: 14px;
}

.filter-list input[type="checkbox"] {
    width: 18px;
    height: 18px;
}

.courses-main {
    background-color: #fff;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.courses-toolbar {
    display: flex;
    justify-content: space-between;
    gap: 20px;
    margin-bottom: 30px;
}

.search-box {
    display: flex;
    gap: 10px;
    flex: 1;
}

.search-box input {
    flex: 1;
    padding: 12px 15px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 15px;
}

.search-btn {
    padding: 12px 30px;
    background-color: #1a73e8;
    color: #fff;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 15px;
}

.sort-options select {
    padding: 12px 15px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 14px;
    background-color: #fff;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}

.pagination {
    display: flex;
    justify-content: center;
    gap: 10px;
}

.page-btn {
    padding: 10px 15px;
    border: 1px solid #ddd;
    background-color: #fff;
    color: #666;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s;
}

.page-btn:hover,
.page-btn.active {
    background-color: #1a73e8;
    color: #fff;
    border-color: #1a73e8;
}

/* 课程详情页 */
.course-detail-hero {
    background: linear-gradient(135deg, #0066cc 0%, #0099ff 100%);
    color: #fff;
    padding: 60px 0;
}

.course-detail-header {
    display: grid;
    grid-template-columns: 1fr 400px;
    gap: 50px;
}

.breadcrumb {
    font-size: 14px;
    margin-bottom: 20px;
    opacity: 0.9;
}

.breadcrumb a {
    color: #fff;
    text-decoration: none;
}

.course-detail-info h1 {
    font-size: 38px;
    margin-bottom: 15px;
}

.course-subtitle {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.95;
}

.course-highlights {
    display: flex;
    gap: 30px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.highlight-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 15px;
}

.highlight-item svg {
    width: 20px;
    height: 20px;
    stroke-width: 2;
}

.course-actions {
    display: flex;
    gap: 15px;
}

.course-detail-preview {
    background-color: rgba(255,255,255,0.1);
    border-radius: 12px;
    padding: 20px;
}

.video-preview {
    background-color: rgba(0,0,0,0.3);
    border-radius: 8px;
    height: 250px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    cursor: pointer;
}

.play-button-large {
    width: 80px;
    height: 80px;
    background-color: rgba(255,255,255,0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: #1a73e8;
    margin-bottom: 15px;
}

.course-content {
    padding: 60px 0;
}

.course-layout {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: 30px;
}

.course-main-content {
    background-color: #fff;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.content-tabs {
    display: flex;
    gap: 30px;
    border-bottom: 2px solid #e9ecef;
    margin-bottom: 30px;
}

.tab-btn {
    padding: 15px 0;
    background: none;
    border: none;
    font-size: 16px;
    color: #666;
    cursor: pointer;
    border-bottom: 3px solid transparent;
    transition: all 0.3s;
}

.tab-btn.active {
    color: #1a73e8;
    border-bottom-color: #1a73e8;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.tab-content h2 {
    font-size: 28px;
    margin-bottom: 20px;
}

.tab-content h3 {
    font-size: 22px;
    margin: 30px 0 15px;
}

.learning-outcomes {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 15px;
    margin: 20px 0;
}

.outcome-item {
    padding: 12px;
    background-color: #e8f0fe;
    border-radius: 6px;
    color: #333;
}

.target-audience {
    list-style: none;
    padding-left: 0;
}

.target-audience li {
    padding: 10px 0;
    padding-left: 25px;
    position: relative;
}

.target-audience li:before {
    content: "→";
    position: absolute;
    left: 0;
    color: #1a73e8;
}

.course-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.feature-box {
    padding: 25px;
    background-color: #f8f9fa;
    border-radius: 8px;
}

.feature-box h4 {
    font-size: 18px;
    margin-bottom: 10px;
    color: #333;
}

.feature-box p {
    color: #666;
    font-size: 14px;
    line-height: 1.6;
}

.teacher-intro {
    display: flex;
    gap: 25px;
    padding: 25px;
    background-color: #f8f9fa;
    border-radius: 8px;
}

.teacher-avatar-large {
    width: 100px;
    height: 100px;
    background-color: #1a73e8;
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 40px;
    font-weight: bold;
    flex-shrink: 0;
}

.teacher-info-detail h4 {
    font-size: 22px;
    margin-bottom: 5px;
}

.teacher-bio {
    color: #666;
    line-height: 1.8;
    margin: 15px 0;
}

.teacher-achievements {
    display: flex;
    gap: 20px;
    font-size: 14px;
    color: #999;
}

.chapter-info {
    color: #666;
    margin-bottom: 30px;
}

.chapter-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.chapter-item {
    border: 1px solid #e9ecef;
    border-radius: 8px;
    overflow: hidden;
}

.chapter-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    background-color: #f8f9fa;
    cursor: pointer;
}

.chapter-header h3 {
    font-size: 18px;
    margin: 0;
}

.expand-btn {
    background: none;
    border: none;
    color: #1a73e8;
    cursor: pointer;
    font-size: 14px;
}

.lesson-list {
    padding: 15px;
}

.lesson-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 12px;
    border-bottom: 1px solid #f0f0f0;
}

.lesson-item:last-child {
    border-bottom: none;
}

.lesson-number {
    color: #999;
    font-size: 14px;
    min-width: 40px;
}

.lesson-title {
    flex: 1;
    color: #333;
}

.lesson-duration {
    color: #999;
    font-size: 14px;
}

.btn-trial {
    padding: 5px 15px;
    background-color: #e8f0fe;
    color: #1a73e8;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 13px;
}

.lesson-lock {
    font-size: 16px;
}

.reviews-summary {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 40px;
    margin-bottom: 40px;
    padding: 30px;
    background-color: #f8f9fa;
    border-radius: 8px;
}

.rating-score {
    text-align: center;
}

.score-number {
    font-size: 56px;
    font-weight: bold;
    color: #1a73e8;
    margin-bottom: 10px;
}

.score-stars {
    font-size: 24px;
    color: #ffa502;
    margin-bottom: 10px;
}

.rating-breakdown {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.rating-bar {
    display: flex;
    align-items: center;
    gap: 15px;
}

.rating-bar span:first-child {
    min-width: 40px;
    color: #666;
}

.bar {
    flex: 1;
    height: 8px;
    background-color: #e9ecef;
    border-radius: 4px;
    overflow: hidden;
}

.fill {
    height: 100%;
    background-color: #ffa502;
}

.rating-bar span:last-child {
    min-width: 40px;
    color: #999;
    font-size: 14px;
}

.reviews-list {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.review-item {
    padding: 25px;
    background-color: #f8f9fa;
    border-radius: 8px;
}

.review-text {
    color: #666;
    line-height: 1.8;
    margin-bottom: 15px;
}

.review-helpful button {
    padding: 8px 15px;
    background-color: #fff;
    border: 1px solid #ddd;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
}

.course-sidebar {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.sidebar-card {
    background-color: #fff;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.sidebar-card h3 {
    font-size: 20px;
    margin-bottom: 20px;
}

.info-item {
    display: flex;
    justify-content: space-between;
    padding: 12px 0;
    border-bottom: 1px solid #f0f0f0;
}

.info-item:last-child {
    border-bottom: none;
}

.info-label {
    color: #666;
}

.info-value {
    color: #333;
    font-weight: 500;
}

.related-course {
    padding: 15px 0;
    border-bottom: 1px solid #f0f0f0;
}

.related-course:last-child {
    border-bottom: none;
}

.related-course h4 {
    font-size: 16px;
    margin-bottom: 5px;
}

.related-course p {
    font-size: 13px;
    color: #999;
    margin-bottom: 8px;
}

.related-course a {
    color: #1a73e8;
    text-decoration: none;
    font-size: 14px;
}

/* 会员购买页面 */
.pricing-section {
    padding: 60px 0;
}

.billing-toggle {
    text-align: center;
    margin-bottom: 50px;
}

.toggle-btn {
    padding: 12px 30px;
    border: 2px solid #1a73e8;
    background-color: #fff;
    color: #1a73e8;
    cursor: pointer;
    font-size: 15px;
    transition: all 0.3s;
    margin: 0 -1px;
}

.toggle-btn:first-child {
    border-radius: 6px 0 0 6px;
}

.toggle-btn:last-child {
    border-radius: 0 6px 6px 0;
}

.toggle-btn.active {
    background-color: #1a73e8;
    color: #fff;
}

.discount {
    background-color: #ff4757;
    color: #fff;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 12px;
    margin-left: 5px;
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.pricing-detail-card {
    background-color: #fff;
    border-radius: 12px;
    padding: 40px 30px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
    position: relative;
    border: 2px solid transparent;
    transition: all 0.3s;
}

.pricing-detail-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
}

.pricing-detail-card.featured {
    border-color: #1a73e8;
    transform: scale(1.05);
}

.popular-badge {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    background-color: #1a73e8;
    color: #fff;
    padding: 5px 20px;
    border-radius: 20px;
    font-size: 14px;
}

.pricing-detail-card h3 {
    font-size: 26px;
    margin-bottom: 20px;
    color: #333;
}

.price-display {
    margin: 20px 0;
}

.price {
    font-size: 48px;
    font-weight: bold;
    color: #1a73e8;
}

.period {
    font-size: 18px;
    color: #666;
}

.plan-desc {
    color: #666;
    margin-bottom: 30px;
    line-height: 1.8;
}

.features-list {
    margin: 30px 0;
}

.features-list h4 {
    font-size: 16px;
    margin-bottom: 15px;
    color: #333;
}

.feature-item {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 10px 0;
    color: #666;
}

.check {
    color: #1a73e8;
    font-weight: bold;
    font-size: 18px;
}

.buy-btn {
    width: 100%;
    margin-top: 20px;
}

/* 会员权益 */
.membership-benefits {
    padding: 80px 0;
    background-color: #f5f7fa;
}

.membership-benefits h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 50px;
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.benefit-card {
    background-color: #fff;
    padding: 35px 25px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.benefit-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto 20px;
    color: #1a73e8;
}

.benefit-icon svg {
    width: 100%;
    height: 100%;
    stroke-width: 2;
}

.benefit-card h3 {
    font-size: 20px;
    margin-bottom: 12px;
}

.benefit-card p {
    color: #666;
    line-height: 1.8;
}

/* 对比表格 */
.comparison-section {
    padding: 80px 0;
    background-color: #fff;
}

.comparison-section h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 40px;
}

.comparison-table {
    overflow-x: auto;
}

.comparison-table table {
    width: 100%;
    border-collapse: collapse;
    background-color: #fff;
}

.comparison-table th,
.comparison-table td {
    padding: 15px;
    text-align: center;
    border: 1px solid #e9ecef;
}

.comparison-table th {
    background-color: #f8f9fa;
    font-weight: 600;
    color: #333;
}

.comparison-table td {
    color: #666;
}

/* FAQ */
.faq-section {
    padding: 80px 0;
    background-color: #f5f7fa;
}

.faq-section h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 40px;
}

.faq-list {
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    background-color: #fff;
    padding: 25px;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.faq-item h4 {
    font-size: 18px;
    color: #333;
    margin-bottom: 12px;
}

.faq-item p {
    color: #666;
    line-height: 1.8;
}

/* 学习中心 */
.learning-dashboard {
    padding: 60px 0;
}

.dashboard-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 30px;
}

.dashboard-sidebar {
    background-color: #fff;
    border-radius: 12px;
    padding: 30px;
    height: fit-content;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.user-profile {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 30px;
    border-bottom: 1px solid #e9ecef;
}

.avatar {
    width: 80px;
    height: 80px;
    background-color: #1a73e8;
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    font-weight: bold;
    margin: 0 auto 15px;
}

.user-profile h3 {
    font-size: 20px;
    margin-bottom: 5px;
    color: #333;
}

.user-profile p {
    font-size: 14px;
    color: #999;
}

.member-expire {
    font-size: 13px;
    color: #666;
    margin-top: 5px;
}

.dashboard-nav {
    display: flex;
    flex-direction: column;
}

.dashboard-nav .nav-item {
    padding: 12px 15px;
    text-decoration: none;
    color: #666;
    border-radius: 6px;
    margin-bottom: 5px;
    transition: all 0.3s;
}

.dashboard-nav .nav-item:hover,
.dashboard-nav .nav-item.active {
    background-color: #e8f0fe;
    color: #1a73e8;
}

.dashboard-content {
    background-color: #fff;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.content-section {
    display: none;
}

.content-section.active {
    display: block;
}

.content-section h2 {
    font-size: 28px;
    margin-bottom: 30px;
    color: #333;
}

.filter-tabs {
    display: flex;
    gap: 15px;
}

.filter-tab {
    padding: 8px 20px;
    background-color: #f8f9fa;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    color: #666;
    transition: all 0.3s;
}

.filter-tab.active {
    background-color: #1a73e8;
    color: #fff;
}

.learning-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.stat-card {
    background-color: #f8f9fa;
    padding: 25px;
    border-radius: 8px;
}

.stat-card h3 {
    font-size: 14px;
    color: #999;
    margin-bottom: 10px;
}

.stat-value {
    font-size: 28px;
    font-weight: bold;
    color: #1a73e8;
}

.my-courses-list {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.my-course-card {
    display: grid;
    grid-template-columns: 200px 1fr auto;
    gap: 25px;
    padding: 25px;
    background-color: #f8f9fa;
    border-radius: 8px;
}

.course-thumbnail {
    width: 200px;
    height: 120px;
    background: linear-gradient(135deg, #1a73e8 0%, #4285f4 100%);
    border-radius: 8px;
}

.course-details h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.course-teacher {
    font-size: 14px;
    color: #999;
    margin-bottom: 15px;
}

.progress-info {
    margin-bottom: 10px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: #e9ecef;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 8px;
}

.progress-fill {
    height: 100%;
    background-color: #1a73e8;
    transition: width 0.3s;
}

.progress-text {
    font-size: 13px;
    color: #666;
}

.last-learn {
    font-size: 13px;
    color: #999;
}

.course-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.progress-overview {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

.progress-chart,
.progress-summary {
    background-color: #f8f9fa;
    padding: 30px;
    border-radius: 8px;
}

.chart-placeholder {
    text-align: center;
    padding: 40px 20px;
}

.chart-bars {
    display: flex;
    justify-content: space-around;
    align-items: flex-end;
    height: 200px;
    margin-top: 20px;
}

.bar {
    width: 40px;
    background-color: #1a73e8;
    border-radius: 4px 4px 0 0;
    position: relative;
    display: flex;
    align-items: flex-end;
    justify-content: center;
}

.bar span {
    position: absolute;
    bottom: -25px;
    font-size: 12px;
    color: #666;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    padding: 15px 0;
    border-bottom: 1px solid #e9ecef;
}

.summary-item:last-child {
    border-bottom: none;
}

.certificates-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 25px;
}

.certificate-card {
    background-color: #f8f9fa;
    border-radius: 8px;
    overflow: hidden;
}

.certificate-preview {
    background: linear-gradient(135deg, #0066cc 0%, #0099ff 100%);
    color: #fff;
    padding: 40px;
    text-align: center;
}

.cert-name {
    font-size: 24px;
    font-weight: bold;
    margin: 15px 0;
}

.cert-date {
    font-size: 14px;
    opacity: 0.9;
}

.certificate-info {
    padding: 20px;
}

.certificate-info h4 {
    font-size: 18px;
    margin-bottom: 10px;
}

.certificate-info p {
    font-size: 14px;
    color: #666;
    margin-bottom: 8px;
}

.cert-actions {
    display: flex;
    gap: 10px;
    margin-top: 15px;
}

.notes-list,
.homework-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.note-item,
.homework-item {
    padding: 20px;
    background-color: #f8f9fa;
    border-radius: 8px;
}

.note-header,
.homework-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.note-header h4,
.homework-header h4 {
    font-size: 18px;
}

.note-date {
    font-size: 13px;
    color: #999;
}

.note-course,
.homework-course {
    font-size: 14px;
    color: #999;
    margin-bottom: 10px;
}

.note-content {
    color: #666;
    line-height: 1.8;
    margin-bottom: 15px;
}

.note-actions {
    display: flex;
    gap: 15px;
}

.homework-status {
    padding: 5px 12px;
    border-radius: 4px;
    font-size: 13px;
}

.homework-status.completed {
    background-color: #d4edda;
    color: #155724;
}

.homework-status.pending {
    background-color: #fff3cd;
    color: #856404;
}

.homework-date {
    font-size: 13px;
    color: #999;
    margin-bottom: 10px;
}

.homework-score {
    margin: 15px 0;
}

.homework-score strong {
    font-size: 24px;
    color: #1a73e8;
}

.teacher-comment {
    padding: 15px;
    background-color: #fff;
    border-radius: 6px;
    margin: 15px 0;
    line-height: 1.8;
    color: #666;
}

.settings-form {
    display: grid;
    gap: 30px;
}

.form-section {
    background-color: #f8f9fa;
    padding: 30px;
    border-radius: 8px;
}

.form-section h3 {
    font-size: 22px;
    margin-bottom: 20px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: #333;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 15px;
    font-family: inherit;
}

.member-info {
    padding: 20px;
    background-color: #fff;
    border-radius: 6px;
    margin-bottom: 20px;
}

.member-info p {
    margin-bottom: 10px;
    color: #666;
}

/* 学员作品 */
.works-section {
    padding: 60px 0;
}

.works-filter {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 10px 25px;
    background-color: #fff;
    border: 2px solid #ddd;
    border-radius: 6px;
    cursor: pointer;
    font-size: 15px;
    color: #666;
    transition: all 0.3s;
}

.filter-btn.active {
    background-color: #1a73e8;
    color: #fff;
    border-color: #1a73e8;
}

.works-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.work-card {
    background-color: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
    transition: all 0.3s;
}

.work-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
}

.work-image {
    width: 100%;
    height: 220px;
    background: linear-gradient(135deg, #1a73e8 0%, #4285f4 100%);
    position: relative;
}

.work-overlay {
    position: absolute;
    inset: 0;
    background-color: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.3s;
}

.work-card:hover .work-overlay {
    opacity: 1;
}

.work-info {
    padding: 20px;
}

.work-info h3 {
    font-size: 18px;
    margin-bottom: 10px;
}

.work-author,
.work-course {
    font-size: 14px;
    color: #999;
    margin-bottom: 8px;
}

.work-stats {
    display: flex;
    gap: 20px;
    font-size: 14px;
    color: #666;
}

.success-stories {
    padding: 80px 0;
    background-color: #f5f7fa;
}

.success-stories h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 50px;
}

.stories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.story-card {
    background-color: #fff;
    padding: 35px;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.story-avatar {
    width: 60px;
    height: 60px;
    background-color: #1a73e8;
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: bold;
    margin-bottom: 15px;
}

.story-card h3 {
    font-size: 20px;
    margin-bottom: 5px;
}

.story-title {
    font-size: 16px;
    color: #1a73e8;
    margin-bottom: 15px;
}

.story-content {
    color: #666;
    line-height: 1.8;
    margin-bottom: 15px;
}

.story-achievement {
    font-size: 13px;
    color: #999;
    padding-top: 15px;
    border-top: 1px solid #e9ecef;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav {
        gap: 15px;
        font-size: 14px;
    }
    
    .hero h1 {
        font-size: 32px;
    }
    
    .hero-stats {
        flex-wrap: wrap;
        gap: 30px;
    }
    
    .course-detail-header {
        grid-template-columns: 1fr;
    }
    
    .courses-layout,
    .dashboard-layout {
        grid-template-columns: 1fr;
    }
    
    .course-layout {
        grid-template-columns: 1fr;
    }
    
    .my-course-card {
        grid-template-columns: 1fr;
    }
    
    .progress-overview {
        grid-template-columns: 1fr;
    }
}

/* 名师团队页面 */
.teachers-section {
    padding: 60px 0;
}

.teachers-filter {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.teachers-grid-detail {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.teacher-detail-card {
    background-color: #fff;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.teacher-header {
    display: flex;
    gap: 30px;
    margin-bottom: 30px;
    padding-bottom: 30px;
    border-bottom: 2px solid #f0f0f0;
}

.teacher-basic-info h3 {
    font-size: 28px;
    margin-bottom: 10px;
}

.teacher-tags {
    display: flex;
    gap: 10px;
    margin-top: 15px;
    flex-wrap: wrap;
}

.tag {
    padding: 6px 15px;
    background-color: #e8f0fe;
    color: #1a73e8;
    border-radius: 20px;
    font-size: 13px;
}

.teacher-content {
    display: grid;
    gap: 30px;
}

.teacher-intro h4,
.teacher-courses h4 {
    font-size: 20px;
    margin-bottom: 15px;
    color: #333;
}

.teacher-intro p {
    color: #666;
    line-height: 1.8;
}

.teacher-stats-detail {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    padding: 25px;
    background-color: #f8f9fa;
    border-radius: 8px;
}

.teacher-stats-detail .stat-item {
    text-align: center;
}

.teacher-stats-detail .stat-number {
    font-size: 32px;
    font-weight: bold;
    color: #1a73e8;
    display: block;
    margin-bottom: 5px;
}

.teacher-stats-detail .stat-label {
    font-size: 14px;
    color: #666;
}

.course-list-simple {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.course-list-simple a {
    padding: 12px 15px;
    background-color: #f8f9fa;
    border-radius: 6px;
    text-decoration: none;
    color: #333;
    transition: all 0.3s;
}

.course-list-simple a:hover {
    background-color: #e8f0fe;
    color: #1a73e8;
}

.join-teacher {
    padding: 80px 0;
    background-color: #f5f7fa;
    text-align: center;
}

.join-teacher h2 {
    font-size: 36px;
    margin-bottom: 15px;
}

.join-teacher > p {
    font-size: 18px;
    color: #666;
    margin-bottom: 50px;
}

.join-requirements {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.requirement-item {
    background-color: #fff;
    padding: 35px 25px;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.requirement-item h4 {
    font-size: 20px;
    margin-bottom: 12px;
    color: #333;
}

.requirement-item p {
    color: #666;
    line-height: 1.8;
}

/* 帮助中心特定样式 */
.faq-container {
    max-width: 1000px;
    margin: 0 auto;
}

.faq-category {
    margin-bottom: 50px;
}

.faq-category h3 {
    font-size: 26px;
    margin-bottom: 25px;
    color: #333;
    padding-bottom: 15px;
    border-bottom: 3px solid #1a73e8;
}

.ticket-section {
    padding: 80px 0;
    background-color: #fff;
}

.ticket-section h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 15px;
}

.ticket-section > p {
    text-align: center;
    color: #666;
    margin-bottom: 40px;
    font-size: 18px;
}

.ticket-form {
    max-width: 800px;
    margin: 0 auto;
    background-color: #f8f9fa;
    padding: 40px;
    border-radius: 12px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.form-hint {
    font-size: 13px;
    color: #999;
    margin-top: 5px;
}

.contact-section {
    padding: 80px 0;
    background-color: #fff;
}

.contact-section h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 50px;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.contact-card {
    background-color: #f8f9fa;
    padding: 40px 30px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.contact-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto 20px;
    color: #1a73e8;
}

.contact-icon svg {
    width: 100%;
    height: 100%;
    stroke-width: 2;
}

.contact-card h3 {
    font-size: 22px;
    margin-bottom: 15px;
    color: #333;
}

.contact-detail {
    font-size: 20px;
    font-weight: bold;
    color: #1a73e8;
    margin: 10px 0;
}

.contact-time {
    font-size: 14px;
    color: #999;
    margin-bottom: 10px;
}

.contact-card p {
    color: #666;
    line-height: 1.8;
}

/* 响应式优化 */
@media (max-width: 768px) {
    .teacher-header {
        flex-direction: column;
        text-align: center;
    }
    
    .teacher-stats-detail {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .join-requirements {
        grid-template-columns: 1fr;
    }
}