/* =============================================
   抖音揭秘 - 汽车改装与视频社区
   原创配色方案：深海夜蓝 + 燃橙 + 月白
   主色：#0A1628（深海夜蓝）
   强调色：#FF6B00（燃橙）
   辅助色：#1A2E4A（中蓝）
   文字色：#F0F4F8（月白）
   ============================================= */

:root {
    --primary: #0A1628;
    --secondary: #1A2E4A;
    --accent: #FF6B00;
    --accent-light: #FF8C33;
    --text-light: #F0F4F8;
    --text-muted: #8FA3B8;
    --white: #FFFFFF;
    --card-bg: #112038;
    --border: #1E3A5F;
    --gradient: linear-gradient(135deg, #0A1628 0%, #1A2E4A 100%);
    --accent-gradient: linear-gradient(135deg, #FF6B00 0%, #FF4500 100%);
    --font-main: 'PingFang SC', 'Microsoft YaHei', '微软雅黑', sans-serif;
    --radius: 8px;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    background-color: var(--primary);
    color: var(--text-light);
    line-height: 1.7;
    overflow-x: hidden;
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--accent-light);
}

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

ul {
    list-style: none;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===== 头部导航 ===== */
.header {
    background: var(--primary);
    border-bottom: 2px solid var(--accent);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 20px rgba(255, 107, 0, 0.2);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo a {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--white);
}

.logo img {
    width: 50px;
    height: 50px;
    object-fit: contain;
    border-radius: 50%;
    border: 2px solid var(--accent);
}

.logo h1 {
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--white);
    letter-spacing: 2px;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav ul {
    display: flex;
    gap: 8px;
    align-items: center;
}

.nav ul li a {
    color: var(--text-light);
    font-size: 0.95rem;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: 20px;
    transition: var(--transition);
    white-space: nowrap;
}

.nav ul li a:hover {
    background: var(--accent);
    color: var(--white);
}

/* ===== 搜索栏 ===== */
.search-bar {
    background: var(--secondary);
    padding: 10px 0;
    border-top: 1px solid var(--border);
}

.search-bar form {
    display: flex;
    gap: 10px;
    max-width: 600px;
    margin: 0 auto;
}

.search-bar input {
    flex: 1;
    padding: 10px 18px;
    background: var(--primary);
    border: 1px solid var(--border);
    border-radius: 25px;
    color: var(--text-light);
    font-size: 0.95rem;
    outline: none;
    transition: var(--transition);
}

.search-bar input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(255, 107, 0, 0.15);
}

.search-bar input::placeholder {
    color: var(--text-muted);
}

.search-bar button {
    padding: 10px 24px;
    background: var(--accent-gradient);
    color: var(--white);
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 600;
    transition: var(--transition);
}

.search-bar button:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 15px rgba(255, 107, 0, 0.4);
}

/* ===== Hero 区域 ===== */
.hero {
    position: relative;
    min-height: 600px;
    display: flex;
    align-items: center;
    overflow: hidden;
    background: var(--primary);
}

.hero-bg {
    position: absolute;
    inset: 0;
    z-index: 0;
}

.hero-bg img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.45;
}

.hero-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(10, 22, 40, 0.95) 0%, rgba(10, 22, 40, 0.5) 60%, transparent 100%);
}

.hero-content {
    position: relative;
    z-index: 2;
    padding: 80px 0;
}

.hero-badge {
    display: inline-block;
    background: var(--accent);
    color: var(--white);
    padding: 5px 16px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 20px;
    letter-spacing: 1px;
}

.hero h2 {
    font-size: 3.2rem;
    font-weight: 900;
    line-height: 1.2;
    margin-bottom: 16px;
    color: var(--white);
}

.hero h2 span {
    color: var(--accent);
}

.hero p {
    font-size: 1.15rem;
    color: var(--text-muted);
    max-width: 520px;
    margin-bottom: 32px;
    line-height: 1.8;
}

.hero-btns {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    background: var(--accent-gradient);
    color: var(--white);
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 700;
    transition: var(--transition);
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(255, 107, 0, 0.5);
    color: var(--white);
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    background: transparent;
    color: var(--white);
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    border: 2px solid rgba(255, 255, 255, 0.4);
    transition: var(--transition);
    cursor: pointer;
}

.btn-secondary:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(255, 107, 0, 0.08);
}

.hero-stats {
    display: flex;
    gap: 40px;
    margin-top: 48px;
    padding-top: 32px;
    border-top: 1px solid var(--border);
}

.hero-stats .stat-item {
    text-align: left;
}

.hero-stats .stat-num {
    font-size: 2rem;
    font-weight: 900;
    color: var(--accent);
    display: block;
}

.hero-stats .stat-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* ===== 通用 Section 样式 ===== */
.section {
    padding: 80px 0;
}

.section-alt {
    background: var(--secondary);
}

.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-tag {
    display: inline-block;
    background: rgba(255, 107, 0, 0.15);
    color: var(--accent);
    padding: 5px 16px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 14px;
    border: 1px solid rgba(255, 107, 0, 0.3);
}

.section-header h2 {
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 14px;
}

.section-header p {
    font-size: 1rem;
    color: var(--text-muted);
    max-width: 560px;
    margin: 0 auto;
}

/* ===== 视频卡片 ===== */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.video-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(255, 107, 0, 0.2);
    border-color: var(--accent);
}

.video-thumbnail {
    position: relative;
    aspect-ratio: 16/9;
    overflow: hidden;
    cursor: pointer;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}

.video-thumbnail:hover img {
    transform: scale(1.05);
}

.play-btn {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    width: 56px;
    height: 56px;
    background: rgba(255, 107, 0, 0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    z-index: 2;
}

.play-btn::after {
    content: '';
    width: 0;
    height: 0;
    border-top: 12px solid transparent;
    border-bottom: 12px solid transparent;
    border-left: 20px solid white;
    margin-left: 4px;
}

.video-thumbnail.playing .play-btn {
    transform: translate(-50%, -50%) scale(1);
}

.video-overlay {
    position: absolute;
    inset: 0;
    background: rgba(10, 22, 40, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition);
    z-index: 1;
}

.video-thumbnail.playing .video-overlay {
    opacity: 1;
}

.video-overlay span {
    color: var(--white);
    font-size: 0.9rem;
    font-weight: 600;
    margin-top: 70px;
}

.duration {
    position: absolute;
    bottom: 10px;
    right: 10px;
    background: rgba(0, 0, 0, 0.75);
    color: var(--white);
    padding: 3px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    z-index: 3;
}

.video-info {
    padding: 16px;
}

.video-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--white);
    margin-bottom: 10px;
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.category {
    background: rgba(255, 107, 0, 0.15);
    color: var(--accent);
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 0.78rem;
    font-weight: 600;
}

.stats {
    display: flex;
    gap: 12px;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.video-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.tag {
    background: var(--secondary);
    color: var(--text-muted);
    padding: 2px 8px;
    border-radius: 10px;
    font-size: 0.75rem;
    border: 1px solid var(--border);
}

/* ===== 功能模块卡片 ===== */
.module-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 24px;
}

.module-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 28px 24px;
    border: 1px solid var(--border);
    transition: var(--transition);
    text-align: center;
}

.module-card:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow);
}

.module-icon {
    width: 60px;
    height: 60px;
    background: rgba(255, 107, 0, 0.12);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 18px;
    font-size: 1.8rem;
    border: 2px solid rgba(255, 107, 0, 0.25);
}

.module-card h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 10px;
}

.module-card p {
    font-size: 0.88rem;
    color: var(--text-muted);
    line-height: 1.7;
}

/* ===== 专家展示 ===== */
.expert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 28px;
}

.expert-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.expert-card:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow);
}

.expert-photo {
    width: 100%;
    aspect-ratio: 1/1;
    object-fit: cover;
}

.expert-info {
    padding: 20px;
}

.expert-info h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 4px;
}

.expert-role {
    color: var(--accent);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 12px;
}

.expert-info p {
    font-size: 0.88rem;
    color: var(--text-muted);
    line-height: 1.7;
    margin-bottom: 14px;
}

.expert-btns {
    display: flex;
    gap: 10px;
}

.expert-btns a {
    flex: 1;
    text-align: center;
    padding: 8px 12px;
    border-radius: 20px;
    font-size: 0.82rem;
    font-weight: 600;
    transition: var(--transition);
}

.expert-btns .btn-contact {
    background: var(--accent-gradient);
    color: var(--white);
}

.expert-btns .btn-works {
    background: transparent;
    color: var(--accent);
    border: 1px solid var(--accent);
}

.expert-btns .btn-works:hover {
    background: rgba(255, 107, 0, 0.1);
}

/* ===== 合作品牌 ===== */
.partner-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 20px;
}

.partner-item {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-muted);
    transition: var(--transition);
    min-height: 80px;
    text-align: center;
}

.partner-item:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(255, 107, 0, 0.05);
}

/* ===== 用户评价 ===== */
.review-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 24px;
}

.review-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 24px;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.review-card:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow);
}

.review-header {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 16px;
}

.reviewer-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--white);
    flex-shrink: 0;
}

.reviewer-info h4 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--white);
}

.reviewer-info span {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.review-stars {
    color: #FFD700;
    font-size: 0.9rem;
    margin-bottom: 12px;
}

.review-card p {
    font-size: 0.9rem;
    color: var(--text-muted);
    line-height: 1.8;
}

/* ===== FAQ ===== */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--card-bg);
    border-radius: var(--radius);
    margin-bottom: 12px;
    border: 1px solid var(--border);
    overflow: hidden;
    transition: var(--transition);
}

.faq-item.active {
    border-color: var(--accent);
}

.faq-question {
    padding: 20px 24px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1rem;
    font-weight: 600;
    color: var(--white);
    transition: var(--transition);
}

.faq-question:hover {
    color: var(--accent);
}

.faq-question::after {
    content: '+';
    font-size: 1.4rem;
    color: var(--accent);
    transition: var(--transition);
    flex-shrink: 0;
}

.faq-item.active .faq-question::after {
    content: '−';
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.3s ease;
    padding: 0 24px;
}

.faq-item.active .faq-answer {
    max-height: 400px;
    padding: 0 24px 20px;
}

.faq-answer p {
    color: var(--text-muted);
    font-size: 0.92rem;
    line-height: 1.8;
}

/* ===== 联系我们 ===== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: start;
}

.contact-info h3 {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 20px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 14px;
    margin-bottom: 18px;
    padding: 16px;
    background: var(--card-bg);
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

.contact-icon {
    width: 40px;
    height: 40px;
    background: rgba(255, 107, 0, 0.12);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: 4px;
}

.contact-item p {
    font-size: 0.88rem;
    color: var(--text-muted);
}

.contact-qr {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
}

.contact-qr .qr-item {
    text-align: center;
}

.contact-qr img {
    width: 150px;
    height: auto;
    border-radius: var(--radius);
    border: 2px solid var(--border);
    margin-bottom: 8px;
}

.contact-qr span {
    font-size: 0.85rem;
    color: var(--text-muted);
    display: block;
}

/* ===== 社区入口 ===== */
.community-entry {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
}

.entry-item {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
}

.entry-item:hover {
    border-color: var(--accent);
    transform: translateY(-3px);
}

.entry-item .entry-icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

.entry-item h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--white);
    margin-bottom: 6px;
}

.entry-item p {
    font-size: 0.82rem;
    color: var(--text-muted);
}

/* ===== AI 赋能区域 ===== */
.ai-section {
    background: linear-gradient(135deg, #0A1628 0%, #0D2040 50%, #1A2E4A 100%);
    position: relative;
    overflow: hidden;
}

.ai-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255, 107, 0, 0.08) 0%, transparent 70%);
    pointer-events: none;
}

.ai-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.ai-text h2 {
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 16px;
    line-height: 1.3;
}

.ai-text h2 span {
    color: var(--accent);
}

.ai-text p {
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 24px;
}

.ai-features {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.ai-feature-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 18px;
    background: rgba(255, 107, 0, 0.06);
    border-radius: var(--radius);
    border-left: 3px solid var(--accent);
}

.ai-feature-item span {
    font-size: 0.92rem;
    color: var(--text-light);
}

.ai-image img {
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
    border: 1px solid var(--border);
}

/* ===== How-To 加入社区 ===== */
.howto-steps {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 24px;
    counter-reset: step-counter;
}

.howto-step {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 28px 24px;
    border: 1px solid var(--border);
    text-align: center;
    position: relative;
    transition: var(--transition);
}

.howto-step:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
}

.step-num {
    width: 48px;
    height: 48px;
    background: var(--accent-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: 800;
    color: var(--white);
    margin: 0 auto 16px;
}

.howto-step h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 10px;
}

.howto-step p {
    font-size: 0.88rem;
    color: var(--text-muted);
    line-height: 1.7;
}

/* ===== 面包屑 ===== */
.breadcrumb {
    padding: 14px 0;
    background: var(--secondary);
    border-bottom: 1px solid var(--border);
}

.breadcrumb ul {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.88rem;
}

.breadcrumb li {
    color: var(--text-muted);
}

.breadcrumb li a {
    color: var(--text-muted);
}

.breadcrumb li a:hover {
    color: var(--accent);
}

.breadcrumb li::after {
    content: '›';
    margin-left: 8px;
    color: var(--border);
}

.breadcrumb li:last-child::after {
    display: none;
}

.breadcrumb li:last-child {
    color: var(--accent);
}

/* ===== 页脚 ===== */
.footer {
    background: #060E1A;
    border-top: 2px solid var(--accent);
    padding: 60px 0 0;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 40px;
    padding-bottom: 40px;
}

.footer-col h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 18px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border);
}

.footer-col p {
    font-size: 0.88rem;
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 16px;
}

.footer-col ul li {
    font-size: 0.85rem;
    color: var(--text-muted);
    padding: 4px 0;
    border-bottom: 1px solid rgba(30, 58, 95, 0.4);
}

.footer-logo {
    width: 80px;
    margin-top: 16px;
}

.qrcodes {
    display: flex;
    gap: 16px;
}

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

.qrcode-item img {
    width: 100px;
    height: auto;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    margin-bottom: 6px;
}

.qrcode-item span {
    font-size: 0.78rem;
    color: var(--text-muted);
    display: block;
}

.social-share {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.social-share button {
    padding: 9px 16px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 20px;
    color: var(--text-light);
    font-size: 0.88rem;
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
}

.social-share button:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(255, 107, 0, 0.06);
}

.footer-bottom {
    border-top: 1px solid var(--border);
    padding: 20px 0;
    text-align: center;
}

.footer-bottom p {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* ===== 内页 Banner ===== */
.page-banner {
    background: var(--gradient);
    padding: 60px 0;
    text-align: center;
    border-bottom: 2px solid var(--accent);
    position: relative;
    overflow: hidden;
}

.page-banner::before {
    content: '';
    position: absolute;
    inset: 0;
    background: url('/images/hero_banner.jpg') center/cover no-repeat;
    opacity: 0.12;
}

.page-banner .container {
    position: relative;
    z-index: 1;
}

.page-banner h1 {
    font-size: 2.4rem;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 12px;
}

.page-banner h1 span {
    color: var(--accent);
}

.page-banner p {
    font-size: 1rem;
    color: var(--text-muted);
    max-width: 560px;
    margin: 0 auto;
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
    .hero h2 { font-size: 2.4rem; }
    .ai-content { grid-template-columns: 1fr; gap: 40px; }
    .contact-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
    .header .container { flex-direction: column; gap: 12px; }
    .nav ul { flex-wrap: wrap; justify-content: center; gap: 4px; }
    .nav ul li a { padding: 6px 12px; font-size: 0.85rem; }
    .hero h2 { font-size: 1.8rem; }
    .hero-stats { flex-wrap: wrap; gap: 20px; }
    .section { padding: 50px 0; }
    .section-header h2 { font-size: 1.7rem; }
    .video-grid { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
    .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 480px) {
    .hero h2 { font-size: 1.5rem; }
    .hero-btns { flex-direction: column; }
    .btn-primary, .btn-secondary { text-align: center; justify-content: center; }
    .video-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; }
    .module-grid { grid-template-columns: repeat(2, 1fr); }
}

/* ===== 动画 ===== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-in {
    animation: fadeInUp 0.6s ease forwards;
}

/* ===== 滚动条 ===== */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: var(--primary);
}

::-webkit-scrollbar-thumb {
    background: var(--accent);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-light);
}

/* ===== 补充样式（修复版）===== */

/* header-inner */
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
}

/* logo-text */
.logo-text {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--white);
    letter-spacing: 2px;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-style: normal;
}

/* nav-toggle (移动端汉堡按钮) */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 6px;
}
.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--white);
    border-radius: 2px;
    transition: var(--transition);
}

/* nav-cta */
.nav-cta {
    background: var(--accent-gradient) !important;
    color: var(--white) !important;
    padding: 6px 16px !important;
    border-radius: 20px !important;
    font-weight: 600;
}
.nav-cta:hover {
    opacity: 0.85;
}

/* page-banner h2 */
.page-banner h2 {
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    font-weight: 800;
    color: var(--white);
    margin-bottom: 12px;
}

/* entry-item h3 (社区入口) */
.entry-item h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--white);
    margin: 8px 0 4px;
}
.entry-item {
    display: block;
    text-decoration: none;
    text-align: center;
    padding: 24px 16px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-light);
}
.entry-item:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(255,107,0,0.2);
    color: var(--white);
}

/* filter-bar */
.filter-bar {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 32px;
    padding: 16px 20px;
    background: var(--card-bg);
    border-radius: var(--radius);
    border: 1px solid var(--border);
}
.filter-label {
    color: var(--text-muted);
    font-size: 0.9rem;
    white-space: nowrap;
}
.filter-btn {
    padding: 6px 18px;
    border: 1px solid var(--border);
    background: transparent;
    color: var(--text-light);
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.85rem;
    transition: var(--transition);
    font-family: var(--font-main);
}
.filter-btn:hover,
.filter-btn.active {
    background: var(--accent-gradient);
    border-color: var(--accent);
    color: var(--white);
}

/* news-section / news-item */
.news-section {
    background: var(--secondary);
}
.news-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.news-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 20px;
    background: var(--card-bg);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    transition: var(--transition);
}
.news-item:hover {
    border-color: var(--accent);
}
.news-tag {
    background: rgba(255,107,0,0.15);
    color: var(--accent);
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 0.78rem;
    white-space: nowrap;
    border: 1px solid rgba(255,107,0,0.3);
}
.news-title {
    flex: 1;
    color: var(--text-light);
    font-size: 0.95rem;
    transition: var(--transition);
}
.news-title:hover {
    color: var(--accent);
}
.news-date {
    color: var(--text-muted);
    font-size: 0.82rem;
    white-space: nowrap;
}

/* honor-grid / honor-item */
.honor-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 24px;
}
.honor-item {
    text-align: center;
    padding: 32px 20px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: var(--transition);
}
.honor-item:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
}
.honor-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}
.honor-item h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 8px;
}
.honor-item p {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* content-block */
.content-block {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 32px;
}
.content-block p {
    margin-bottom: 16px;
    color: var(--text-light);
    line-height: 1.8;
}
.content-block p:last-child {
    margin-bottom: 0;
}

/* cat-grid / cat-item */
.video-categories {
    margin-top: 40px;
}
.video-categories h3 {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 20px;
}
.cat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 16px;
}
.cat-item {
    display: block;
    text-align: center;
    padding: 24px 16px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: var(--transition);
    color: var(--text-light);
}
.cat-item:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
    color: var(--white);
}
.cat-icon {
    font-size: 2rem;
    display: block;
    margin-bottom: 10px;
}
.cat-item h4 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 6px;
}
.cat-item p {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: 8px;
}
.cat-count {
    font-size: 0.78rem;
    color: var(--accent);
    background: rgba(255,107,0,0.1);
    padding: 2px 10px;
    border-radius: 10px;
}

/* video-card-wrap */
.video-card-wrap {
    transition: var(--transition);
}

/* expert-avatar-placeholder */
.expert-avatar-placeholder {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    flex-shrink: 0;
    margin: 0 auto 16px;
}

/* expert-cert */
.expert-cert {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-top: 10px;
    padding: 8px 12px;
    background: rgba(255,107,0,0.08);
    border-radius: 6px;
    border-left: 3px solid var(--accent);
}

/* vid-date */
.vid-date {
    position: absolute;
    bottom: 8px;
    left: 8px;
    background: rgba(0,0,0,0.7);
    color: var(--text-muted);
    font-size: 0.72rem;
    padding: 2px 8px;
    border-radius: 4px;
    z-index: 2;
}

/* review-date */
.review-date {
    display: block;
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 10px;
}

/* contact-form */
.contact-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}
.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.form-group label {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 600;
}
.form-group input,
.form-group select,
.form-group textarea {
    padding: 12px 16px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--white);
    font-family: var(--font-main);
    font-size: 0.95rem;
    transition: var(--transition);
    outline: none;
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(255,107,0,0.15);
}
.form-group select option {
    background: var(--secondary);
}

/* 响应式补充 */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }
    .header-inner {
        flex-wrap: wrap;
    }
    .news-item {
        flex-wrap: wrap;
    }
    .filter-bar {
        gap: 8px;
    }
    .honor-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .cat-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    .content-block {
        padding: 20px;
    }
}

@media (max-width: 480px) {
    .honor-grid {
        grid-template-columns: 1fr 1fr;
    }
    .cat-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .filter-btn {
        font-size: 0.78rem;
        padding: 5px 12px;
    }
}