/* ===================================================
   17c一起草 - 官方网站样式表
   域名: r25d11.cn
   版本: 1.0.0
   =================================================== */

/* ---- 基础重置与变量 ---- */
:root {
    --primary: #c0392b;
    --primary-dark: #922b21;
    --primary-light: #e74c3c;
    --accent: #d4a017;
    --accent-light: #f0c040;
    --dark: #0d0d0d;
    --dark2: #1a1a2e;
    --dark3: #16213e;
    --dark4: #0f3460;
    --gray1: #1e1e2e;
    --gray2: #2a2a3e;
    --gray3: #3a3a4e;
    --text-light: #f0f0f0;
    --text-muted: #a0a0b0;
    --text-white: #ffffff;
    --border: rgba(255,255,255,0.1);
    --shadow: 0 4px 20px rgba(0,0,0,0.4);
    --radius: 10px;
    --radius-lg: 16px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
    background-color: var(--dark);
    color: var(--text-light);
    line-height: 1.7;
    overflow-x: hidden;
}

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

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

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

ul, ol {
    list-style: none;
}

/* ---- 通用布局 ---- */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 70px 0;
}

.section-alt {
    background-color: var(--gray1);
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-white);
    margin-bottom: 12px;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    margin-top: 8px;
    border-radius: 2px;
}

.section-subtitle {
    color: var(--text-muted);
    font-size: 1rem;
    margin-bottom: 40px;
    max-width: 600px;
}

.section-header {
    margin-bottom: 40px;
}

.text-center { text-align: center; }
.text-primary { color: var(--primary-light); }
.text-accent { color: var(--accent-light); }

/* ---- 按钮样式 ---- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: 6px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: var(--transition);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    box-shadow: 0 4px 15px rgba(192,57,43,0.4);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-light), var(--primary));
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(192,57,43,0.5);
    color: #fff;
}

.btn-accent {
    background: linear-gradient(135deg, var(--accent), #b8860b);
    color: #fff;
    box-shadow: 0 4px 15px rgba(212,160,23,0.4);
}

.btn-accent:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(212,160,23,0.5);
    color: #fff;
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary);
    color: var(--primary-light);
}

.btn-outline:hover {
    background: var(--primary);
    color: #fff;
}

.btn-sm {
    padding: 8px 18px;
    font-size: 0.85rem;
}

/* ---- 顶部公告栏 ---- */
.top-bar {
    background: linear-gradient(90deg, var(--primary-dark), var(--dark4));
    padding: 8px 0;
    font-size: 0.82rem;
    color: rgba(255,255,255,0.85);
}

.top-bar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.top-bar-links a {
    color: rgba(255,255,255,0.8);
    margin-left: 16px;
    font-size: 0.82rem;
}

.top-bar-links a:hover {
    color: var(--accent-light);
}

/* ---- 头部导航 ---- */
.site-header {
    background: rgba(13,13,13,0.97);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 2px 20px rgba(0,0,0,0.5);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 0;
    gap: 20px;
}

.site-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    flex-shrink: 0;
}

.site-logo img {
    height: 44px;
    width: auto;
}

.logo-text {
    display: flex;
    flex-direction: column;
}

.logo-brand {
    font-size: 1.3rem;
    font-weight: 800;
    color: var(--text-white);
    line-height: 1.2;
    letter-spacing: 1px;
}

.logo-brand span {
    color: var(--primary-light);
}

.logo-tagline {
    font-size: 0.72rem;
    color: var(--text-muted);
    letter-spacing: 2px;
}

/* 主导航 */
.main-nav {
    display: flex;
    align-items: center;
    gap: 4px;
}

.main-nav a {
    color: var(--text-light);
    font-size: 0.92rem;
    padding: 8px 14px;
    border-radius: 6px;
    transition: var(--transition);
    white-space: nowrap;
    font-weight: 500;
}

.main-nav a:hover,
.main-nav a.active {
    color: var(--text-white);
    background: rgba(192,57,43,0.2);
}

.main-nav a.active {
    color: var(--primary-light);
}

/* 搜索框 */
.header-search {
    display: flex;
    align-items: center;
    background: var(--gray2);
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 6px 16px;
    gap: 8px;
    min-width: 200px;
    transition: var(--transition);
}

.header-search:focus-within {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(192,57,43,0.15);
}

.header-search input {
    background: none;
    border: none;
    outline: none;
    color: var(--text-light);
    font-size: 0.88rem;
    width: 100%;
}

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

.header-search button {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0;
    font-size: 1rem;
    transition: var(--transition);
}

.header-search button:hover {
    color: var(--primary-light);
}

/* 搜索下方栏 */
.search-bar-row {
    background: var(--gray1);
    border-bottom: 1px solid var(--border);
    padding: 10px 0;
}

.search-bar-row .container {
    display: flex;
    align-items: center;
    gap: 16px;
}

.search-bar-full {
    display: flex;
    align-items: center;
    background: var(--gray2);
    border: 1px solid var(--border);
    border-radius: 30px;
    padding: 8px 20px;
    gap: 10px;
    flex: 1;
    max-width: 600px;
    transition: var(--transition);
}

.search-bar-full:focus-within {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(192,57,43,0.15);
}

.search-bar-full input {
    background: none;
    border: none;
    outline: none;
    color: var(--text-light);
    font-size: 0.95rem;
    flex: 1;
}

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

.search-bar-full button {
    background: var(--primary);
    border: none;
    color: #fff;
    cursor: pointer;
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.88rem;
    transition: var(--transition);
}

.search-bar-full button:hover {
    background: var(--primary-light);
}

.search-hot-tags {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    font-size: 0.82rem;
}

.search-hot-tags span {
    color: var(--text-muted);
}

.search-hot-tags a {
    color: var(--text-muted);
    padding: 3px 10px;
    background: var(--gray3);
    border-radius: 12px;
    font-size: 0.8rem;
    transition: var(--transition);
}

.search-hot-tags a:hover {
    color: var(--primary-light);
    background: rgba(192,57,43,0.2);
}

/* 移动端汉堡菜单 */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 4px;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-light);
    border-radius: 2px;
    transition: var(--transition);
}

/* ---- 英雄横幅 ---- */
.hero-banner {
    position: relative;
    min-height: 560px;
    display: flex;
    align-items: center;
    overflow: hidden;
    background: var(--dark2);
}

.hero-bg {
    position: absolute;
    inset: 0;
    background-image: url('../images/banner_hero.jpg');
    background-size: cover;
    background-position: center;
    filter: brightness(0.45);
    z-index: 0;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(13,13,13,0.8) 0%, rgba(192,57,43,0.15) 50%, rgba(13,13,13,0.7) 100%);
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 680px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(192,57,43,0.3);
    border: 1px solid rgba(192,57,43,0.5);
    color: var(--accent-light);
    padding: 5px 14px;
    border-radius: 20px;
    font-size: 0.82rem;
    margin-bottom: 20px;
    backdrop-filter: blur(4px);
}

.hero-title {
    font-size: clamp(2rem, 5vw, 3.2rem);
    font-weight: 800;
    color: var(--text-white);
    line-height: 1.25;
    margin-bottom: 18px;
}

.hero-title .highlight {
    color: var(--primary-light);
    display: inline-block;
}

.hero-desc {
    font-size: 1.05rem;
    color: rgba(255,255,255,0.8);
    margin-bottom: 32px;
    max-width: 520px;
    line-height: 1.8;
}

.hero-actions {
    display: flex;
    gap: 14px;
    flex-wrap: wrap;
}

.hero-stats {
    position: absolute;
    bottom: 30px;
    right: 0;
    z-index: 2;
    display: flex;
    gap: 30px;
}

.hero-stat {
    text-align: center;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,255,255,0.1);
    padding: 14px 22px;
    border-radius: var(--radius);
}

.hero-stat-num {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--accent-light);
    line-height: 1;
}

.hero-stat-label {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 4px;
}

/* ---- 视频卡片网格 ---- */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

.video-grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

.video-grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

.video-card {
    background: var(--gray1);
    border-radius: var(--radius);
    overflow: hidden;
    transition: var(--transition);
    border: 1px solid var(--border);
    cursor: pointer;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.5);
    border-color: rgba(192,57,43,0.4);
}

.video-thumb {
    position: relative;
    overflow: hidden;
    aspect-ratio: 16/9;
    background: var(--gray2);
}

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

.video-card:hover .video-thumb img {
    transform: scale(1.06);
}

.video-play-btn {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0,0,0,0.3);
    opacity: 0;
    transition: var(--transition);
}

.video-card:hover .video-play-btn {
    opacity: 1;
}

.play-icon {
    width: 56px;
    height: 56px;
    background: rgba(192,57,43,0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transform: scale(0.8);
    transition: var(--transition);
    box-shadow: 0 4px 20px rgba(192,57,43,0.5);
}

.video-card:hover .play-icon {
    transform: scale(1);
}

.play-icon::after {
    content: '';
    border-left: 18px solid #fff;
    border-top: 11px solid transparent;
    border-bottom: 11px solid transparent;
    margin-left: 4px;
}

.video-duration {
    position: absolute;
    bottom: 8px;
    right: 8px;
    background: rgba(0,0,0,0.75);
    color: #fff;
    font-size: 0.75rem;
    padding: 2px 7px;
    border-radius: 4px;
}

.video-tag {
    position: absolute;
    top: 8px;
    left: 8px;
    background: var(--primary);
    color: #fff;
    font-size: 0.72rem;
    padding: 3px 8px;
    border-radius: 4px;
    font-weight: 600;
}

.video-info {
    padding: 14px;
}

.video-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-white);
    margin-bottom: 8px;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 0.78rem;
    color: var(--text-muted);
}

.video-meta span {
    display: flex;
    align-items: center;
    gap: 4px;
}

.video-author {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-top: 10px;
    padding-top: 10px;
    border-top: 1px solid var(--border);
}

.video-author-avatar {
    width: 26px;
    height: 26px;
    border-radius: 50%;
    background: var(--gray3);
    overflow: hidden;
}

.video-author-name {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* ---- 分类标签栏 ---- */
.category-tabs {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 30px;
}

.category-tab {
    padding: 7px 18px;
    border-radius: 20px;
    font-size: 0.88rem;
    cursor: pointer;
    border: 1px solid var(--border);
    color: var(--text-muted);
    background: var(--gray2);
    transition: var(--transition);
}

.category-tab:hover,
.category-tab.active {
    background: var(--primary);
    border-color: var(--primary);
    color: #fff;
}

/* ---- 专家展示 ---- */
.expert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 24px;
}

.expert-card {
    background: var(--gray1);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border);
    transition: var(--transition);
    text-align: center;
}

.expert-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
    border-color: rgba(192,57,43,0.4);
}

.expert-avatar {
    width: 100%;
    aspect-ratio: 1;
    overflow: hidden;
    position: relative;
}

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

.expert-card:hover .expert-avatar img {
    transform: scale(1.05);
}

.expert-body {
    padding: 18px;
}

.expert-name {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-white);
    margin-bottom: 4px;
}

.expert-role {
    font-size: 0.82rem;
    color: var(--primary-light);
    margin-bottom: 10px;
}

.expert-desc {
    font-size: 0.82rem;
    color: var(--text-muted);
    line-height: 1.6;
    margin-bottom: 14px;
}

.expert-awards {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    justify-content: center;
    margin-bottom: 14px;
}

.award-badge {
    background: rgba(212,160,23,0.15);
    border: 1px solid rgba(212,160,23,0.3);
    color: var(--accent-light);
    font-size: 0.72rem;
    padding: 3px 8px;
    border-radius: 4px;
}

.expert-actions {
    display: flex;
    gap: 8px;
    justify-content: center;
}

/* ---- 合作品牌Logo墙 ---- */
.partner-wall {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    justify-content: center;
    align-items: center;
}

.partner-logo {
    background: var(--gray2);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 24px;
    min-width: 140px;
    text-align: center;
    transition: var(--transition);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-muted);
}

.partner-logo:hover {
    border-color: var(--primary);
    color: var(--text-white);
    background: rgba(192,57,43,0.1);
}

/* ---- 用户评价 ---- */
.review-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.review-card {
    background: var(--gray1);
    border-radius: var(--radius);
    padding: 22px;
    border: 1px solid var(--border);
    transition: var(--transition);
    position: relative;
}

.review-card::before {
    content: '"';
    position: absolute;
    top: 14px;
    right: 20px;
    font-size: 4rem;
    color: rgba(192,57,43,0.15);
    font-family: Georgia, serif;
    line-height: 1;
}

.review-card:hover {
    border-color: rgba(192,57,43,0.3);
    box-shadow: var(--shadow);
}

.review-stars {
    display: flex;
    gap: 3px;
    margin-bottom: 12px;
}

.star {
    color: var(--accent-light);
    font-size: 0.95rem;
}

.review-text {
    font-size: 0.9rem;
    color: var(--text-light);
    line-height: 1.7;
    margin-bottom: 16px;
}

.review-author {
    display: flex;
    align-items: center;
    gap: 10px;
}

.review-avatar {
    width: 38px;
    height: 38px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--dark4));
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
    color: #fff;
    flex-shrink: 0;
}

.review-name {
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--text-white);
}

.review-date {
    font-size: 0.75rem;
    color: var(--text-muted);
}

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

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

.faq-item:hover {
    border-color: rgba(192,57,43,0.3);
}

.faq-question {
    padding: 18px 22px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--gray1);
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-white);
    transition: var(--transition);
    user-select: none;
}

.faq-question:hover {
    background: var(--gray2);
}

.faq-question.active {
    color: var(--primary-light);
    background: rgba(192,57,43,0.1);
}

.faq-icon {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--gray3);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    transition: var(--transition);
    flex-shrink: 0;
}

.faq-question.active .faq-icon {
    background: var(--primary);
    transform: rotate(45deg);
}

.faq-answer {
    display: none;
    padding: 16px 22px;
    background: var(--gray2);
    font-size: 0.9rem;
    color: var(--text-muted);
    line-height: 1.8;
    border-top: 1px solid var(--border);
}

.faq-answer.open {
    display: block;
}

/* ---- 联系信息 ---- */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 20px;
}

.contact-card {
    background: var(--gray1);
    border-radius: var(--radius);
    padding: 24px;
    border: 1px solid var(--border);
    text-align: center;
    transition: var(--transition);
}

.contact-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow);
}

.contact-icon {
    width: 54px;
    height: 54px;
    border-radius: 50%;
    background: rgba(192,57,43,0.15);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin: 0 auto 14px;
    border: 1px solid rgba(192,57,43,0.3);
}

.contact-label {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: 6px;
}

.contact-value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-white);
}

/* ---- QR码展示 ---- */
.qr-section {
    display: flex;
    gap: 30px;
    flex-wrap: wrap;
    justify-content: center;
}

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

.qr-code {
    width: 130px;
    height: 130px;
    background: #fff;
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 10px;
    padding: 8px;
    overflow: hidden;
}

.qr-code canvas {
    width: 100% !important;
    height: 100% !important;
}

.qr-label {
    font-size: 0.82rem;
    color: var(--text-muted);
}

/* ---- 社交分享 ---- */
.share-buttons {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.share-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: var(--transition);
    color: #fff;
}

.share-wechat { background: #07c160; }
.share-weibo { background: #e6162d; }
.share-douyin { background: #010101; border: 1px solid #333; }
.share-bilibili { background: #00a1d6; }

.share-btn:hover {
    opacity: 0.85;
    transform: translateY(-2px);
    color: #fff;
}

/* ---- 底部页脚 ---- */
.site-footer {
    background: var(--dark2);
    border-top: 1px solid var(--border);
    padding-top: 60px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid var(--border);
}

.footer-brand img {
    height: 42px;
    margin-bottom: 16px;
}

.footer-brand-desc {
    font-size: 0.88rem;
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 20px;
}

.footer-col-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-white);
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.footer-links a {
    font-size: 0.85rem;
    color: var(--text-muted);
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--primary-light);
    padding-left: 4px;
}

.footer-bottom {
    padding: 20px 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.footer-copyright {
    font-size: 0.82rem;
    color: var(--text-muted);
}

.footer-copyright a {
    color: var(--text-muted);
}

.footer-copyright a:hover {
    color: var(--primary-light);
}

.footer-update {
    font-size: 0.78rem;
    color: var(--text-muted);
}

/* ---- 面包屑 ---- */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: var(--text-muted);
    padding: 14px 0;
}

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

.breadcrumb a:hover {
    color: var(--primary-light);
}

.breadcrumb-sep {
    color: var(--gray3);
}

.breadcrumb-current {
    color: var(--text-light);
}

/* ---- 内页横幅 ---- */
.page-banner {
    background: linear-gradient(135deg, var(--dark2) 0%, var(--dark4) 100%);
    padding: 50px 0;
    border-bottom: 1px solid var(--border);
    position: relative;
    overflow: hidden;
}

.page-banner::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(192,57,43,0.15) 0%, transparent 70%);
    border-radius: 50%;
}

.page-banner-title {
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--text-white);
    margin-bottom: 10px;
}

.page-banner-desc {
    font-size: 1rem;
    color: var(--text-muted);
    max-width: 600px;
    line-height: 1.7;
}

/* ---- AI赋能模块 ---- */
.ai-feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.ai-feature-card {
    background: linear-gradient(135deg, var(--gray1), var(--gray2));
    border-radius: var(--radius-lg);
    padding: 28px;
    border: 1px solid var(--border);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.ai-feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
}

.ai-feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
    border-color: rgba(192,57,43,0.3);
}

.ai-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.ai-title {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-white);
    margin-bottom: 10px;
}

.ai-desc {
    font-size: 0.88rem;
    color: var(--text-muted);
    line-height: 1.7;
}

/* ---- 社区功能模块 ---- */
.community-features {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
}

.community-item {
    background: var(--gray1);
    border-radius: var(--radius);
    padding: 22px 16px;
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.community-item:hover {
    border-color: var(--primary);
    background: rgba(192,57,43,0.08);
    transform: translateY(-3px);
}

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

.community-item-title {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-white);
    margin-bottom: 6px;
}

.community-item-desc {
    font-size: 0.78rem;
    color: var(--text-muted);
    line-height: 1.5;
}

/* ---- How-To 指南 ---- */
.howto-steps {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    position: relative;
}

.howto-steps::before {
    content: '';
    position: absolute;
    top: 36px;
    left: 12%;
    right: 12%;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    z-index: 0;
}

.howto-step {
    text-align: center;
    position: relative;
    z-index: 1;
}

.step-num {
    width: 72px;
    height: 72px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 800;
    color: #fff;
    margin: 0 auto 16px;
    box-shadow: 0 4px 15px rgba(192,57,43,0.4);
}

.step-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-white);
    margin-bottom: 8px;
}

.step-desc {
    font-size: 0.82rem;
    color: var(--text-muted);
    line-height: 1.6;
}

/* ---- 统计数据 ---- */
.stats-row {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.stat-item {
    text-align: center;
    padding: 30px 20px;
    background: var(--gray1);
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

.stat-num {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary-light);
    line-height: 1;
    margin-bottom: 8px;
}

.stat-label {
    font-size: 0.88rem;
    color: var(--text-muted);
}

/* ---- 标签云 ---- */
.tag-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag {
    padding: 5px 14px;
    background: var(--gray2);
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.82rem;
    color: var(--text-muted);
    transition: var(--transition);
    cursor: pointer;
}

.tag:hover {
    background: rgba(192,57,43,0.2);
    border-color: var(--primary);
    color: var(--primary-light);
}

/* ---- 通知栏 ---- */
.notice-bar {
    background: rgba(192,57,43,0.1);
    border: 1px solid rgba(192,57,43,0.3);
    border-radius: var(--radius);
    padding: 12px 18px;
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 24px;
    font-size: 0.88rem;
    color: var(--text-light);
}

.notice-icon {
    color: var(--primary-light);
    font-size: 1rem;
    flex-shrink: 0;
}

/* ---- 加载动画 ---- */
.skeleton {
    background: linear-gradient(90deg, var(--gray2) 25%, var(--gray3) 50%, var(--gray2) 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: 4px;
}

@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ---- 弹幕效果 ---- */
.danmaku-container {
    position: relative;
    overflow: hidden;
    height: 40px;
    background: rgba(0,0,0,0.3);
    border-radius: var(--radius);
    margin-bottom: 16px;
}

.danmaku-text {
    position: absolute;
    white-space: nowrap;
    font-size: 0.88rem;
    color: rgba(255,255,255,0.8);
    animation: danmaku-move 12s linear infinite;
    top: 50%;
    transform: translateY(-50%);
}

@keyframes danmaku-move {
    from { right: -100%; }
    to { right: 110%; }
}

/* ---- 响应式设计 ---- */
@media (max-width: 1200px) {
    .video-grid-4 { grid-template-columns: repeat(3, 1fr); }
    .footer-grid { grid-template-columns: 1.5fr 1fr 1fr; }
    .footer-grid > *:last-child { grid-column: 1 / -1; }
}

@media (max-width: 992px) {
    .video-grid-3,
    .video-grid-4 { grid-template-columns: repeat(2, 1fr); }
    .ai-feature-grid { grid-template-columns: repeat(2, 1fr); }
    .community-features { grid-template-columns: repeat(2, 1fr); }
    .howto-steps { grid-template-columns: repeat(2, 1fr); }
    .howto-steps::before { display: none; }
    .stats-row { grid-template-columns: repeat(2, 1fr); }
    .hero-stats { position: static; margin-top: 30px; }
    .hero-banner { min-height: auto; padding: 60px 0; }
}

@media (max-width: 768px) {
    .main-nav { display: none; }
    .main-nav.open { 
        display: flex; 
        flex-direction: column; 
        position: absolute; 
        top: 100%; 
        left: 0; 
        right: 0; 
        background: var(--dark); 
        padding: 16px; 
        border-bottom: 1px solid var(--border);
        gap: 4px;
    }
    .mobile-menu-btn { display: flex; }
    .header-search { display: none; }
    .video-grid,
    .video-grid-3,
    .video-grid-4 { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .section { padding: 50px 0; }
    .hero-title { font-size: 1.8rem; }
    .hero-stats { flex-direction: row; justify-content: flex-start; }
    .expert-grid { grid-template-columns: repeat(2, 1fr); }
    .ai-feature-grid { grid-template-columns: 1fr; }
    .community-features { grid-template-columns: repeat(2, 1fr); }
    .howto-steps { grid-template-columns: 1fr; }
    .stats-row { grid-template-columns: repeat(2, 1fr); }
    .search-hot-tags { display: none; }
}

@media (max-width: 480px) {
    .video-grid,
    .video-grid-3,
    .video-grid-4 { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; }
    .expert-grid { grid-template-columns: 1fr; }
    .community-features { grid-template-columns: repeat(2, 1fr); }
    .stats-row { grid-template-columns: repeat(2, 1fr); }
    .hero-actions { flex-direction: column; }
    .hero-actions .btn { width: 100%; justify-content: center; }
    .section-title { font-size: 1.6rem; }
    .page-banner-title { font-size: 1.6rem; }
}

/* ---- 工具类 ---- */
.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 32px; }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.mb-4 { margin-bottom: 32px; }
.d-flex { display: flex; }
.align-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: 16px; }
.w-100 { width: 100%; }

/* ---- 滚动条样式 ---- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--dark); }
::-webkit-scrollbar-thumb { background: var(--gray3); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary); }

/* ---- 选中文字颜色 ---- */
::selection { background: rgba(192,57,43,0.4); color: #fff; }