/* ============================================================
   XVIDEO 影视传媒 - 主样式文件
   网站：singlecloud.com.cn
   版本：2025.03
   ============================================================ */

/* ---- CSS变量 ---- */
:root {
    --brand-red: #E8001C;
    --brand-red-dark: #B5001A;
    --brand-red-light: #FF1A35;
    --brand-bg: #0D0D14;
    --brand-bg2: #111118;
    --brand-card: #141420;
    --brand-card2: #1A1A28;
    --brand-border: #2A2A3E;
    --brand-white: #E8E8F0;
    --brand-muted: #8888AA;
    --brand-accent: #7C3AED;
    --font-main: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', 'WenQuanYi Micro Hei', Arial, sans-serif;
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --shadow-card: 0 4px 24px rgba(0,0,0,0.3);
    --shadow-hover: 0 8px 40px rgba(0,0,0,0.5);
    --transition: all 0.3s cubic-bezier(0.4,0,0.2,1);
}

/* ---- Reset ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
    font-family: var(--font-main);
    background: var(--brand-bg);
    color: var(--brand-white);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}
img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { cursor: pointer; }
input, textarea, select { font-family: var(--font-main); }

/* ---- 容器 ---- */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ============================================================
   顶部公告栏
   ============================================================ */
.top-notice {
    background: linear-gradient(90deg, var(--brand-red-dark), #7C3AED, var(--brand-red-dark));
    background-size: 200% 100%;
    animation: noticeScroll 8s linear infinite;
    color: #fff;
    text-align: center;
    font-size: 12px;
    padding: 7px 16px;
    letter-spacing: 0.5px;
    font-weight: 500;
    white-space: nowrap;
    overflow: hidden;
}
@keyframes noticeScroll {
    0% { background-position: 0% 50%; }
    100% { background-position: 200% 50%; }
}

/* ============================================================
   网站头部
   ============================================================ */
.site-header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(13,13,20,0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--brand-border);
    box-shadow: 0 2px 20px rgba(0,0,0,0.4);
}
.header-inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    gap: 20px;
    height: 64px;
}

/* ---- Logo ---- */
.site-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
    text-decoration: none;
}
.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--brand-red), #7C3AED);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 900;
    color: #fff;
    letter-spacing: -1px;
    flex-shrink: 0;
    box-shadow: 0 2px 12px rgba(232,0,28,0.4);
}
.logo-text { display: flex; flex-direction: column; }
.logo-brand {
    font-size: 20px;
    font-weight: 900;
    color: var(--brand-white);
    letter-spacing: -0.5px;
    line-height: 1.1;
}
.logo-brand span { color: var(--brand-red); }
.logo-sub {
    font-size: 10px;
    color: var(--brand-muted);
    letter-spacing: 0.5px;
    line-height: 1;
}

/* ---- 主导航 ---- */
.main-nav { flex: 1; }
.main-nav ul {
    display: flex;
    align-items: center;
    gap: 2px;
    flex-wrap: nowrap;
}
.main-nav a {
    display: block;
    padding: 6px 10px;
    font-size: 13px;
    font-weight: 500;
    color: var(--brand-muted);
    border-radius: var(--radius-sm);
    transition: var(--transition);
    white-space: nowrap;
}
.main-nav a:hover,
.main-nav a.active {
    color: var(--brand-white);
    background: rgba(255,255,255,0.06);
}
.main-nav a.active { color: var(--brand-red); }

/* ---- 搜索框 ---- */
.header-search {
    display: flex;
    align-items: center;
    background: rgba(255,255,255,0.05);
    border: 1px solid var(--brand-border);
    border-radius: 24px;
    overflow: hidden;
    flex-shrink: 0;
    width: 220px;
    transition: var(--transition);
}
.header-search:focus-within {
    border-color: var(--brand-red);
    background: rgba(232,0,28,0.05);
    width: 260px;
}
.header-search input {
    flex: 1;
    background: none;
    border: none;
    outline: none;
    padding: 8px 14px;
    font-size: 13px;
    color: var(--brand-white);
    min-width: 0;
}
.header-search input::placeholder { color: var(--brand-muted); }
.search-btn {
    background: none;
    border: none;
    padding: 8px 12px;
    color: var(--brand-muted);
    display: flex;
    align-items: center;
    transition: var(--transition);
}
.search-btn:hover { color: var(--brand-red); }
.search-btn svg { width: 16px; height: 16px; }

/* ---- 汉堡菜单 ---- */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    padding: 6px;
    margin-left: auto;
}
.menu-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--brand-muted);
    border-radius: 2px;
    transition: var(--transition);
}

/* ---- 移动端搜索条 ---- */
.nav-search-bar {
    display: none;
    background: var(--brand-bg2);
    border-bottom: 1px solid var(--brand-border);
    padding: 10px 16px;
}
.search-inner {
    display: flex;
    gap: 8px;
    max-width: 600px;
    margin: 0 auto;
}
.search-inner input {
    flex: 1;
    background: rgba(255,255,255,0.05);
    border: 1px solid var(--brand-border);
    border-radius: 8px;
    padding: 9px 14px;
    font-size: 14px;
    color: var(--brand-white);
    outline: none;
}
.search-inner button {
    background: var(--brand-red);
    border: none;
    color: #fff;
    padding: 9px 18px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 600;
    font-family: var(--font-main);
}

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumb {
    background: var(--brand-bg2);
    border-bottom: 1px solid var(--brand-border);
    padding: 10px 0;
    font-size: 13px;
    color: var(--brand-muted);
}
.breadcrumb .container,
.breadcrumb {
    max-width: 1280px;
    margin: 0 auto;
    padding-left: 24px;
    padding-right: 24px;
}
.breadcrumb a { color: var(--brand-muted); transition: var(--transition); }
.breadcrumb a:hover { color: var(--brand-red); }
.breadcrumb .sep { margin: 0 8px; color: var(--brand-border); }
.breadcrumb .current { color: var(--brand-white); }

/* ============================================================
   Hero Banner
   ============================================================ */
.hero-section {
    position: relative;
    min-height: 580px;
    display: flex;
    align-items: center;
    overflow: hidden;
}
.hero-bg {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    transform: scale(1.05);
    filter: brightness(0.4);
}
.hero-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(13,13,20,0.9) 0%, rgba(13,13,20,0.6) 50%, rgba(13,13,20,0.8) 100%);
}
.hero-content {
    position: relative;
    z-index: 2;
    max-width: 1280px;
    margin: 0 auto;
    padding: 60px 24px;
    width: 100%;
}
.hero-badge {
    display: inline-block;
    background: rgba(232,0,28,0.15);
    border: 1px solid rgba(232,0,28,0.3);
    color: var(--brand-red);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 20px;
    letter-spacing: 0.5px;
}
.hero-content h1 {
    font-size: clamp(32px, 5vw, 56px);
    font-weight: 900;
    line-height: 1.2;
    margin-bottom: 20px;
    color: var(--brand-white);
    text-shadow: 0 2px 20px rgba(0,0,0,0.5);
}
.hero-content h1 .brand { color: var(--brand-red); }
.hero-content p {
    font-size: 16px;
    color: rgba(232,232,240,0.8);
    max-width: 600px;
    line-height: 1.8;
    margin-bottom: 32px;
}
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-bottom: 48px; }
.hero-stats {
    display: flex;
    gap: 40px;
    flex-wrap: wrap;
}
.stat-item { text-align: left; }
.stat-num {
    font-size: 28px;
    font-weight: 900;
    color: var(--brand-white);
    line-height: 1;
}
.stat-num span { font-size: 16px; color: var(--brand-red); }
.stat-label { font-size: 12px; color: var(--brand-muted); margin-top: 4px; }

/* ============================================================
   按钮
   ============================================================ */
.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--brand-red);
    color: #fff;
    padding: 12px 28px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 700;
    text-decoration: none;
    transition: var(--transition);
    border: none;
    font-family: var(--font-main);
    box-shadow: 0 4px 20px rgba(232,0,28,0.3);
}
.btn-primary:hover {
    background: var(--brand-red-light);
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(232,0,28,0.4);
}
.btn-outline {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(255,255,255,0.05);
    color: var(--brand-white);
    padding: 12px 28px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    border: 1px solid var(--brand-border);
    transition: var(--transition);
    font-family: var(--font-main);
}
.btn-outline:hover {
    background: rgba(255,255,255,0.1);
    border-color: rgba(255,255,255,0.3);
    transform: translateY(-2px);
}
.btn-sm {
    display: inline-block;
    padding: 7px 16px;
    border-radius: 6px;
    font-size: 12px;
    font-weight: 600;
    background: rgba(255,255,255,0.05);
    border: 1px solid var(--brand-border);
    color: var(--brand-muted);
    transition: var(--transition);
    text-decoration: none;
}
.btn-sm:hover { background: rgba(255,255,255,0.1); color: var(--brand-white); }
.btn-sm.primary {
    background: rgba(232,0,28,0.1);
    border-color: rgba(232,0,28,0.3);
    color: var(--brand-red);
}
.btn-sm.primary:hover { background: var(--brand-red); color: #fff; }

/* ============================================================
   通用Section
   ============================================================ */
.section { padding: 72px 0; }
.section-alt { background: var(--brand-bg2); }
.section-header {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    margin-bottom: 40px;
    gap: 16px;
}
.section-title-group { flex: 1; }
.section-label {
    font-size: 11px;
    font-weight: 700;
    color: var(--brand-red);
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 8px;
}
.section-title {
    font-size: clamp(22px, 3vw, 32px);
    font-weight: 900;
    color: var(--brand-white);
    line-height: 1.2;
}
.section-title span { color: var(--brand-red); }
.section-desc {
    font-size: 14px;
    color: var(--brand-muted);
    margin-top: 8px;
    line-height: 1.7;
}
.view-all {
    font-size: 13px;
    color: var(--brand-red);
    white-space: nowrap;
    transition: var(--transition);
    flex-shrink: 0;
}
.view-all:hover { color: var(--brand-red-light); }

/* ============================================================
   视频卡片
   ============================================================ */
.video-grid { display: grid; gap: 20px; }
.video-grid-4 { grid-template-columns: repeat(4, 1fr); }
.video-grid-3 { grid-template-columns: repeat(3, 1fr); }

.video-card {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition);
    cursor: pointer;
    position: relative;
}
.video-card:hover {
    border-color: rgba(232,0,28,0.3);
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

/* 视频缩略图 */
.video-thumb {
    position: relative;
    aspect-ratio: 16/9;
    overflow: hidden;
    background: var(--brand-bg);
}
.video-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}
.video-card:hover .video-thumb img { transform: scale(1.08); }

/* 播放按钮遮罩 */
.play-overlay {
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition);
}
.video-card:hover .play-overlay { opacity: 1; }
.play-btn {
    width: 52px;
    height: 52px;
    background: rgba(232,0,28,0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transform: scale(0.8);
    transition: var(--transition);
    box-shadow: 0 4px 20px rgba(232,0,28,0.5);
}
.video-card:hover .play-btn { transform: scale(1); }
.play-btn svg {
    width: 22px;
    height: 22px;
    fill: #fff;
    margin-left: 3px;
}

/* 视频时长标签 */
.video-duration {
    position: absolute;
    bottom: 8px;
    right: 8px;
    background: rgba(0,0,0,0.8);
    color: #fff;
    font-size: 11px;
    font-weight: 700;
    padding: 2px 7px;
    border-radius: 4px;
    letter-spacing: 0.5px;
}
.video-tag {
    position: absolute;
    top: 8px;
    left: 8px;
    background: var(--brand-red);
    color: #fff;
    font-size: 10px;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 4px;
    letter-spacing: 0.3px;
}

/* 视频信息 */
.video-info { padding: 14px; }
.video-title {
    font-size: 13px;
    font-weight: 600;
    color: var(--brand-white);
    line-height: 1.5;
    margin-bottom: 10px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.video-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.video-stats { display: flex; gap: 10px; }
.video-stat {
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 11px;
    color: var(--brand-muted);
}
.video-stat svg { width: 12px; height: 12px; }

/* ============================================================
   服务卡片
   ============================================================ */
.services-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.service-card {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-md);
    padding: 28px;
    transition: var(--transition);
}
.service-card:hover {
    border-color: rgba(232,0,28,0.3);
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}
.service-icon {
    font-size: 32px;
    margin-bottom: 16px;
    display: block;
}
.service-card h3 {
    font-size: 16px;
    font-weight: 700;
    color: var(--brand-white);
    margin-bottom: 10px;
}
.service-card p {
    font-size: 13px;
    color: var(--brand-muted);
    line-height: 1.7;
    margin-bottom: 16px;
}
.service-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
    font-size: 11px;
    padding: 3px 10px;
    background: rgba(232,0,28,0.08);
    border: 1px solid rgba(232,0,28,0.2);
    color: var(--brand-red);
    border-radius: 20px;
    font-weight: 500;
}

/* ============================================================
   AI区块
   ============================================================ */
.ai-section {
    position: relative;
    overflow: hidden;
    padding: 80px 0;
}
.ai-bg {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    filter: brightness(0.2);
}
.ai-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(13,13,20,0.95), rgba(13,13,20,0.8));
}
.ai-content { position: relative; z-index: 2; }
.ai-features { display: flex; flex-direction: column; gap: 20px; }
.ai-feature {
    display: flex;
    gap: 16px;
    align-items: flex-start;
    background: rgba(255,255,255,0.04);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-md);
    padding: 20px;
    transition: var(--transition);
}
.ai-feature:hover {
    border-color: rgba(232,0,28,0.3);
    background: rgba(232,0,28,0.05);
}
.ai-feature-icon {
    font-size: 24px;
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    background: rgba(232,0,28,0.1);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
}
.ai-feature h4 {
    font-size: 14px;
    font-weight: 700;
    color: var(--brand-white);
    margin-bottom: 4px;
}
.ai-feature p { font-size: 12px; color: var(--brand-muted); line-height: 1.6; }

/* ============================================================
   专家卡片
   ============================================================ */
.experts-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.expert-card {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
}
.expert-card:hover {
    border-color: rgba(232,0,28,0.3);
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}
.expert-photo { position: relative; aspect-ratio: 4/3; overflow: hidden; background: var(--brand-bg); }
.expert-photo img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.5s ease; }
.expert-card:hover .expert-photo img { transform: scale(1.05); }
.expert-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    background: var(--brand-red);
    color: #fff;
    font-size: 11px;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 20px;
}
.expert-info { padding: 20px; }
.expert-name { font-size: 18px; font-weight: 800; color: var(--brand-white); margin-bottom: 4px; }
.expert-title { font-size: 12px; color: var(--brand-red); font-weight: 600; margin-bottom: 10px; }
.expert-desc { font-size: 13px; color: var(--brand-muted); line-height: 1.7; margin-bottom: 12px; }
.expert-awards { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 16px; }
.award-tag {
    font-size: 10px;
    padding: 3px 8px;
    background: rgba(124,58,237,0.1);
    border: 1px solid rgba(124,58,237,0.25);
    color: #9D6FEF;
    border-radius: 4px;
}
.expert-actions { display: flex; gap: 8px; }

/* ============================================================
   社区卡片
   ============================================================ */
.community-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.community-card {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-md);
    padding: 24px 20px;
    text-align: center;
    transition: var(--transition);
}
.community-card:hover {
    border-color: rgba(232,0,28,0.3);
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}
.community-icon { font-size: 32px; display: block; margin-bottom: 12px; }
.community-card h4 { font-size: 14px; font-weight: 700; color: var(--brand-white); margin-bottom: 8px; }
.community-card p { font-size: 12px; color: var(--brand-muted); line-height: 1.6; margin-bottom: 12px; }
.community-count { font-size: 11px; color: var(--brand-red); font-weight: 600; }

/* ============================================================
   合作伙伴
   ============================================================ */
.partners-row { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; }
.partner-logo {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-sm);
    padding: 14px 24px;
    font-size: 13px;
    font-weight: 600;
    color: var(--brand-muted);
    transition: var(--transition);
}
.partner-logo:hover {
    border-color: rgba(232,0,28,0.3);
    color: var(--brand-white);
    background: rgba(232,0,28,0.05);
}

/* ============================================================
   加入步骤
   ============================================================ */
.join-steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.step-card {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-md);
    padding: 28px 20px;
    text-align: center;
    position: relative;
    transition: var(--transition);
}
.step-card:hover { border-color: rgba(232,0,28,0.3); transform: translateY(-4px); }
.step-num {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--brand-red), #7C3AED);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: 900;
    color: #fff;
    margin: 0 auto 16px;
}
.step-card h4 { font-size: 14px; font-weight: 700; color: var(--brand-white); margin-bottom: 10px; }
.step-card p { font-size: 12px; color: var(--brand-muted); line-height: 1.7; }

/* ============================================================
   联系区块
   ============================================================ */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.contact-info-card {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-lg);
    padding: 32px;
}
.contact-info-card h3 { font-size: 18px; font-weight: 700; color: var(--brand-white); margin-bottom: 24px; }
.contact-item { display: flex; gap: 14px; align-items: flex-start; margin-bottom: 20px; }
.contact-icon {
    font-size: 18px;
    width: 36px;
    height: 36px;
    background: rgba(232,0,28,0.1);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}
.contact-label { font-size: 11px; color: var(--brand-muted); margin-bottom: 2px; }
.contact-value { font-size: 13px; color: var(--brand-white); font-weight: 500; }
.qr-grid { display: flex; gap: 20px; flex-wrap: wrap; }
.qr-item { text-align: center; }
.qr-item img { border-radius: 8px; border: 1px solid var(--brand-border); }
.qr-label { font-size: 11px; color: var(--brand-muted); margin-top: 6px; }

/* ============================================================
   评价卡片
   ============================================================ */
.reviews-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.review-card {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-md);
    padding: 20px;
    transition: var(--transition);
}
.review-card:hover { border-color: rgba(232,0,28,0.2); transform: translateY(-2px); }
.review-stars { color: #F59E0B; font-size: 14px; margin-bottom: 12px; letter-spacing: 2px; }
.review-text { font-size: 13px; color: var(--brand-muted); line-height: 1.7; margin-bottom: 16px; font-style: italic; }
.review-author { display: flex; align-items: center; gap: 10px; }
.author-avatar {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--brand-red), #7C3AED);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 700;
    color: #fff;
    flex-shrink: 0;
}
.author-name { font-size: 13px; font-weight: 600; color: var(--brand-white); }
.author-meta { font-size: 11px; color: var(--brand-muted); }

/* ============================================================
   FAQ
   ============================================================ */
.faq-list { max-width: 900px; margin: 0 auto; display: flex; flex-direction: column; gap: 12px; }
.faq-item {
    background: var(--brand-card);
    border: 1px solid var(--brand-border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition);
}
.faq-item.open { border-color: rgba(232,0,28,0.3); }
.faq-question {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 18px 24px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    color: var(--brand-white);
    transition: var(--transition);
    gap: 16px;
}
.faq-question:hover { color: var(--brand-red); }
.faq-icon {
    font-size: 20px;
    font-weight: 300;
    color: var(--brand-muted);
    flex-shrink: 0;
    transition: var(--transition);
}
.faq-item.open .faq-icon { transform: rotate(45deg); color: var(--brand-red); }
.faq-answer { display: none; }
.faq-item.open .faq-answer { display: block; }
.faq-answer-inner {
    padding: 0 24px 20px;
    font-size: 13px;
    color: var(--brand-muted);
    line-height: 1.8;
    border-top: 1px solid var(--brand-border);
    padding-top: 16px;
}

/* ============================================================
   分享按钮
   ============================================================ */
.share-bar { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.share-label { font-size: 12px; color: var(--brand-muted); }
.share-btn {
    font-size: 11px;
    padding: 4px 12px;
    border-radius: 20px;
    border: 1px solid var(--brand-border);
    background: rgba(255,255,255,0.04);
    color: var(--brand-muted);
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-main);
}
.share-btn:hover { background: rgba(255,255,255,0.1); color: var(--brand-white); }
.share-btn.wechat:hover { border-color: #07C160; color: #07C160; }
.share-btn.weibo:hover { border-color: #E6162D; color: #E6162D; }
.share-btn.douyin:hover { border-color: #FE2C55; color: #FE2C55; }
.share-btn.bilibili:hover { border-color: #00A1D6; color: #00A1D6; }

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
    background: #080810;
    border-top: 1px solid var(--brand-border);
    padding-top: 60px;
}
.footer-logo-section {
    text-align: center;
    padding: 0 24px 40px;
    border-bottom: 1px solid var(--brand-border);
    margin-bottom: 48px;
}
.footer-logo-section .site-logo { justify-content: center; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1.5fr; gap: 40px; margin-bottom: 48px; }
.footer-brand p { font-size: 13px; color: var(--brand-muted); line-height: 1.8; margin-bottom: 8px; }
.footer-col h4 { font-size: 14px; font-weight: 700; color: var(--brand-white); margin-bottom: 16px; }
.footer-col ul { display: flex; flex-direction: column; gap: 8px; }
.footer-col a { font-size: 13px; color: var(--brand-muted); transition: var(--transition); }
.footer-col a:hover { color: var(--brand-red); }
.footer-bottom {
    border-top: 1px solid var(--brand-border);
    padding: 20px 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
}
.footer-copy { font-size: 12px; color: var(--brand-muted); }
.footer-copy a { color: var(--brand-red); }
.footer-links { display: flex; gap: 16px; flex-wrap: wrap; }
.footer-links a { font-size: 12px; color: var(--brand-muted); transition: var(--transition); }
.footer-links a:hover { color: var(--brand-red); }

/* ============================================================
   页面Hero（内页）
   ============================================================ */
.page-hero {
    background: linear-gradient(135deg, var(--brand-bg2) 0%, rgba(232,0,28,0.05) 100%);
    border-bottom: 1px solid var(--brand-border);
    padding: 60px 0;
}
.page-hero h1 {
    font-size: clamp(24px, 4vw, 40px);
    font-weight: 900;
    color: var(--brand-white);
    margin-bottom: 12px;
    line-height: 1.2;
}
.page-hero h1 span { color: var(--brand-red); }
.page-hero p { font-size: 15px; color: var(--brand-muted); line-height: 1.8; max-width: 700px; }

/* ============================================================
   图片加载动画
   ============================================================ */
img { transition: opacity 0.3s ease; }
img.loaded { opacity: 1; }

/* ============================================================
   响应式设计
   ============================================================ */
@media (max-width: 1200px) {
    .video-grid-4 { grid-template-columns: repeat(3, 1fr); }
    .reviews-grid { grid-template-columns: repeat(3, 1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
    .community-grid { grid-template-columns: repeat(4, 1fr); }
}

@media (max-width: 1024px) {
    .main-nav a { padding: 6px 8px; font-size: 12px; }
    .header-search { width: 180px; }
    .ai-content > div { grid-template-columns: 1fr; gap: 40px; }
    .experts-grid { grid-template-columns: repeat(2, 1fr); }
    .join-steps { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 900px) {
    .video-grid-4 { grid-template-columns: repeat(2, 1fr); }
    .video-grid-3 { grid-template-columns: repeat(2, 1fr); }
    .services-grid { grid-template-columns: repeat(2, 1fr); }
    .community-grid { grid-template-columns: repeat(2, 1fr); }
    .reviews-grid { grid-template-columns: repeat(2, 1fr); }
    .contact-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
    .header-search { display: none; }
    .main-nav {
        display: none;
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(13,13,20,0.98);
        backdrop-filter: blur(20px);
        z-index: 999;
        overflow-y: auto;
        padding: 20px;
    }
    .main-nav.open { display: block; }
    .main-nav ul { flex-direction: column; gap: 4px; }
    .main-nav a { padding: 12px 16px; font-size: 15px; }
    .menu-toggle { display: flex; }
    .nav-search-bar { display: block; }
    .hero-section { min-height: 480px; }
    .hero-stats { gap: 20px; }
    .section { padding: 48px 0; }
    .experts-grid { grid-template-columns: 1fr; }
    .join-steps { grid-template-columns: 1fr 1fr; }
    .footer-grid { grid-template-columns: 1fr; }
    .footer-bottom { flex-direction: column; text-align: center; }
}

@media (max-width: 600px) {
    .video-grid-4,
    .video-grid-3 { grid-template-columns: repeat(2, 1fr); }
    .services-grid { grid-template-columns: 1fr; }
    .community-grid { grid-template-columns: repeat(2, 1fr); }
    .reviews-grid { grid-template-columns: 1fr; }
    .join-steps { grid-template-columns: 1fr; }
    .hero-actions { flex-direction: column; }
    .btn-primary, .btn-outline { width: 100%; justify-content: center; }
    .section-header { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 480px) {
    .container { padding: 0 16px; }
    .video-grid-4,
    .video-grid-3 { grid-template-columns: 1fr; }
    .community-grid { grid-template-columns: 1fr; }
    .hero-content { padding: 40px 16px; }
}

/* ============================================================
   打印样式
   ============================================================ */
@media print {
    .site-header, .top-notice, .nav-search-bar, .site-footer { display: none; }
    body { background: #fff; color: #000; }
    .section { padding: 20px 0; }
}