/* =============================================
   51视频 - 主样式文件 style.css
   wyreenms.cn
   原创配色方案：深宇宙紫 + 极光青 + 星光金
   ============================================= */

/* ---- CSS 变量 ---- */
:root {
    --bg-dark:       #0a0b14;
    --bg-main:       #0e0f1c;
    --bg-card:       #131427;
    --bg-hover:      #1a1b30;
    --border:        rgba(120,100,255,.18);
    --border-light:  rgba(120,100,255,.08);

    --primary:       #7c5cfc;
    --primary-light: #a78bfa;
    --primary-dark:  #5b3de8;
    --accent:        #f0c040;
    --accent2:       #38e8c8;
    --danger:        #f87171;

    --text-main:     #f0eeff;
    --text-muted:    #9090b8;
    --text-dim:      #5a5a80;

    --radius:        10px;
    --radius-lg:     18px;
    --radius-xl:     28px;
    --shadow:        0 4px 24px rgba(0,0,0,.5);
    --shadow-lg:     0 8px 48px rgba(0,0,0,.7);
    --transition:    .25s ease;
}

/* ---- 重置 & 基础 ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
    background: var(--bg-main);
    color: var(--text-main);
    font-family: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--primary-light); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent); }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* ---- 无障碍辅助 ---- */
.sr-only {
    position: absolute; width: 1px; height: 1px;
    padding: 0; margin: -1px; overflow: hidden;
    clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}
:focus-visible {
    outline: 2px solid var(--primary-light);
    outline-offset: 3px;
    border-radius: 4px;
}

/* ---- 容器 ---- */
.container { max-width: 1240px; margin: 0 auto; padding: 0 20px; }

/* ---- 顶部公告栏 ---- */
.top-bar {
    background: linear-gradient(90deg, var(--primary-dark), #2a1a6e);
    padding: 7px 0;
    font-size: .78rem;
    color: rgba(255,255,255,.75);
    border-bottom: 1px solid var(--border);
}
.top-bar .container {
    display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap;
}
.top-bar-links { display: flex; gap: 16px; }
.top-bar-links a { color: rgba(255,255,255,.65); font-size: .78rem; }
.top-bar-links a:hover { color: var(--accent); }

/* ---- 导航栏 ---- */
.navbar {
    position: sticky; top: 0; z-index: 1000;
    background: rgba(10,11,20,.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: box-shadow var(--transition);
}
.nav-inner {
    display: flex; align-items: center; justify-content: space-between;
    height: 62px; gap: 20px;
}
.nav-logo {
    display: flex; align-items: center; gap: 10px;
    color: var(--text-main); font-size: 1.15rem; font-weight: 800;
    white-space: nowrap;
}
.logo-icon {
    width: 38px; height: 38px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    font-size: .9rem; font-weight: 900; color: #fff;
    flex-shrink: 0;
}
.logo-51 { color: var(--accent); }
.nav-menu {
    display: flex; align-items: center; gap: 6px; flex: 1; justify-content: center;
}
.nav-menu a {
    color: var(--text-muted); font-size: .88rem; padding: 6px 14px;
    border-radius: 8px; transition: all var(--transition);
}
.nav-menu a:hover, .nav-menu a.active {
    color: var(--text-main); background: var(--bg-hover);
}
.nav-actions { display: flex; align-items: center; gap: 10px; }
.btn-nav {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff; padding: 7px 18px; border-radius: 8px;
    font-size: .82rem; font-weight: 600; white-space: nowrap;
    transition: opacity var(--transition);
}
.btn-nav:hover { opacity: .85; color: #fff; }
.nav-toggle {
    display: none; flex-direction: column; gap: 5px;
    width: 30px; padding: 4px;
}
.nav-toggle span {
    display: block; height: 2px; background: var(--text-muted);
    border-radius: 2px; transition: all var(--transition);
}

/* ---- 搜索栏 ---- */
.search-bar-wrap {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    padding: 14px 0;
}
.search-bar-inner {
    display: flex; gap: 10px; max-width: 640px;
}
.search-input {
    flex: 1; background: var(--bg-dark); border: 1px solid var(--border);
    color: var(--text-main); padding: 10px 16px; border-radius: 10px;
    font-size: .88rem; outline: none; transition: border-color var(--transition);
}
.search-input:focus { border-color: var(--primary); }
.search-input::placeholder { color: var(--text-dim); }
.search-btn {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff; padding: 10px 22px; border-radius: 10px;
    font-size: .88rem; font-weight: 600; white-space: nowrap;
    transition: opacity var(--transition);
}
.search-btn:hover { opacity: .85; }
.search-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.search-tag {
    background: var(--bg-dark); border: 1px solid var(--border);
    color: var(--text-muted); padding: 4px 12px; border-radius: 20px;
    font-size: .78rem; cursor: pointer; transition: all var(--transition);
}
.search-tag:hover { border-color: var(--primary); color: var(--primary-light); }

/* ---- 按钮 ---- */
.btn-primary {
    display: inline-flex; align-items: center; gap: 8px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff; padding: 11px 24px; border-radius: 10px;
    font-size: .9rem; font-weight: 600;
    transition: all var(--transition); border: none; cursor: pointer;
}
.btn-primary:hover { opacity: .88; transform: translateY(-1px); color: #fff; }
.btn-outline {
    display: inline-flex; align-items: center; gap: 8px;
    background: transparent; color: var(--text-main);
    border: 1.5px solid var(--border); padding: 10px 22px; border-radius: 10px;
    font-size: .9rem; font-weight: 600; transition: all var(--transition); cursor: pointer;
}
.btn-outline:hover { border-color: var(--primary); color: var(--primary-light); }
.btn-sm { padding: 6px 14px; border-radius: 7px; font-size: .8rem; font-weight: 600; }
.btn-sm-primary { background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: #fff; }
.btn-sm-primary:hover { opacity: .85; }
.btn-sm-outline { border: 1px solid var(--border); color: var(--text-muted); }
.btn-sm-outline:hover { border-color: var(--primary); color: var(--primary-light); }

/* ---- Hero Banner ---- */
.hero {
    position: relative; min-height: 540px;
    display: flex; align-items: center;
    overflow: hidden; padding: 60px 0;
}
.hero-bg {
    position: absolute; inset: 0;
    background: url('../images/hero_banner.jpg') center/cover no-repeat;
    filter: brightness(.35) saturate(1.2);
}
.hero-overlay {
    position: absolute; inset: 0;
    background: linear-gradient(135deg, rgba(10,11,20,.9) 0%, rgba(60,20,120,.5) 60%, rgba(10,11,20,.8) 100%);
}
.hero-content {
    position: relative; z-index: 2; max-width: 680px;
}
.hero-badge {
    display: inline-flex; align-items: center; gap: 8px;
    background: rgba(124,92,252,.2); border: 1px solid rgba(124,92,252,.4);
    color: var(--primary-light); padding: 6px 16px; border-radius: 20px;
    font-size: .8rem; margin-bottom: 20px;
}
.hero h1 {
    font-size: clamp(2rem, 5vw, 3.2rem);
    font-weight: 900; line-height: 1.2; margin-bottom: 18px;
    text-shadow: 0 2px 20px rgba(0,0,0,.8);
}
.hero h1 .brand { color: var(--accent); }
.hero p {
    color: var(--text-muted); font-size: 1rem; margin-bottom: 28px;
    max-width: 560px; line-height: 1.7;
}
.hero-btns { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 36px; }
.hero-stats {
    display: flex; gap: 28px; flex-wrap: wrap;
    border-top: 1px solid var(--border); padding-top: 24px;
}
.hero-stat .num {
    font-size: 1.5rem; font-weight: 800; color: var(--accent);
}
.hero-stat .label { font-size: .78rem; color: var(--text-muted); }

/* ---- 弹幕 ---- */
.danmaku-wrap {
    position: relative; height: 70px; overflow: hidden;
    background: var(--bg-card); border-radius: var(--radius);
    margin: 16px 0; border: 1px solid var(--border);
}
.danmaku-item {
    position: absolute; white-space: nowrap; font-size: .82rem;
    animation: danmaku-scroll linear infinite;
    right: -200px;
}
@keyframes danmaku-scroll {
    from { transform: translateX(0); }
    to   { transform: translateX(calc(-100vw - 400px)); }
}

/* ---- 统计行 ---- */
.stats-row {
    display: flex; gap: 20px; flex-wrap: wrap; justify-content: center;
}
.stat-item {
    text-align: center; flex: 1; min-width: 120px;
    background: var(--bg-card); border: 1px solid var(--border);
    border-radius: var(--radius-lg); padding: 24px 16px;
    transition: all var(--transition);
}
.stat-item:hover { border-color: var(--primary); transform: translateY(-3px); }
.stat-num {
    font-size: 2rem; font-weight: 900;
    background: linear-gradient(135deg, var(--primary-light), var(--accent));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
.stat-label { font-size: .8rem; color: var(--text-muted); margin-top: 4px; }

/* ---- Section ---- */
.section { padding: 64px 0; }
.section-title {
    font-size: clamp(1.3rem, 3vw, 1.9rem);
    font-weight: 800; text-align: center; margin-bottom: 10px;
}
.section-sub {
    text-align: center; color: var(--text-muted); font-size: .9rem;
    max-width: 600px; margin: 0 auto;
}
.section-divider {
    width: 56px; height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: 2px; margin: 18px auto 36px;
}

/* ---- 视频卡片 ---- */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 20px;
}
.video-card {
    background: var(--bg-card); border: 1px solid var(--border);
    border-radius: var(--radius-lg); overflow: hidden;
    transition: all var(--transition); cursor: pointer;
}
.video-card:hover {
    border-color: var(--primary); transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(124,92,252,.25);
}
.video-thumb {
    position: relative; aspect-ratio: 16/9; overflow: hidden;
    background: var(--bg-dark);
}
.video-thumb img {
    width: 100%; height: 100%; object-fit: cover;
    transition: transform .4s ease;
}
.video-card:hover .video-thumb img { transform: scale(1.06); }
.play-overlay {
    position: absolute; inset: 0;
    display: flex; align-items: center; justify-content: center;
    background: rgba(0,0,0,.0);
    opacity: 0; transition: all var(--transition);
}
.video-card:hover .play-overlay {
    background: rgba(0,0,0,.45); opacity: 1;
}
.play-btn {
    width: 56px; height: 56px;
    background: rgba(124,92,252,.92); border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    transform: scale(.8); transition: transform var(--transition);
    box-shadow: 0 4px 20px rgba(124,92,252,.5);
}
.video-card:hover .play-btn { transform: scale(1); }
.play-btn svg { width: 22px; height: 22px; fill: #fff; margin-left: 3px; }
.video-duration {
    position: absolute; bottom: 8px; right: 8px;
    background: rgba(0,0,0,.8); color: #fff;
    font-size: .72rem; padding: 2px 7px; border-radius: 4px;
}
.video-tag {
    position: absolute; top: 8px; left: 8px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff; font-size: .7rem; padding: 3px 9px; border-radius: 4px;
}
.video-info { padding: 14px 16px 16px; }
.video-title {
    font-size: .88rem; font-weight: 600; color: var(--text-main);
    line-height: 1.4; margin-bottom: 8px;
    display: -webkit-box; -webkit-line-clamp: 2;
    -webkit-box-orient: vertical; overflow: hidden;
}
.video-meta {
    display: flex; gap: 12px; font-size: .75rem; color: var(--text-dim);
}

/* ---- 竖屏视频卡片（TikTok风格） ---- */
.video-grid-vertical {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 16px;
}
.video-card-vertical {
    background: var(--bg-card); border: 1px solid var(--border);
    border-radius: var(--radius-lg); overflow: hidden;
    transition: all var(--transition); cursor: pointer;
}
.video-card-vertical:hover {
    border-color: var(--primary); transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(124,92,252,.25);
}
.video-thumb-vertical {
    position: relative; aspect-ratio: 9/16; overflow: hidden;
    background: var(--bg-dark);
}
.video-thumb-vertical img {
    width: 100%; height: 100%; object-fit: cover;
    transition: transform .4s ease;
}
.video-card-vertical:hover .video-thumb-vertical img { transform: scale(1.06); }
.video-card-vertical .play-overlay {
    position: absolute; inset: 0;
    display: flex; align-items: center; justify-content: center;
    background: rgba(0,0,0,.0);
    opacity: 0; transition: all var(--transition);
}
.video-card-vertical:hover .play-overlay {
    background: rgba(0,0,0,.45); opacity: 1;
}

/* ---- 功能卡片 ---- */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}
.feature-card {
    background: var(--bg-dark); border: 1px solid var(--border);
    border-radius: var(--radius-lg); padding: 28px 24px;
    transition: all var(--transition);
}
.feature-card:hover {
    border-color: var(--primary); transform: translateY(-3px);
    box-shadow: 0 8px 32px rgba(124,92,252,.2);
}
.feature-icon {
    width: 52px; height: 52px;
    background: linear-gradient(135deg, rgba(124,92,252,.2), rgba(56,232,200,.1));
    border: 1px solid var(--border); border-radius: 14px;
    display: flex; align-items: center; justify-content: center;
    font-size: 1.5rem; margin-bottom: 16px;
}
.feature-card h3 {
    font-size: .95rem; font-weight: 700; color: var(--text-main);
    margin-bottom: 10px;
}
.feature-card p { font-size: .83rem; color: var(--text-muted); line-height: 1.6; }

/* ---- 专家卡片 ---- */
.expert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 24px;
}
.expert-card {
    background: var(--bg-dark); border: 1px solid var(--border);
    border-radius: var(--radius-lg); padding: 28px 24px;
    text-align: center; transition: all var(--transition);
}
.expert-card:hover {
    border-color: var(--primary); transform: translateY(-3px);
    box-shadow: 0 8px 32px rgba(124,92,252,.2);
}
.expert-avatar {
    width: 90px; height: 90px; border-radius: 50%;
    overflow: hidden; margin: 0 auto 16px;
    border: 3px solid var(--primary);
}
.expert-avatar img { width: 100%; height: 100%; object-fit: cover; }
.expert-name { font-size: 1.05rem; font-weight: 700; margin-bottom: 4px; }
.expert-role {
    display: inline-block;
    background: rgba(124,92,252,.15); color: var(--primary-light);
    font-size: .75rem; padding: 3px 10px; border-radius: 20px; margin-bottom: 12px;
}
.expert-desc {
    font-size: .82rem; color: var(--text-muted); line-height: 1.6; margin-bottom: 14px;
}
.expert-tags { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; margin-bottom: 12px; }
.expert-tag {
    background: var(--bg-card); border: 1px solid var(--border);
    color: var(--text-muted); font-size: .72rem; padding: 3px 9px; border-radius: 4px;
}
.expert-btns { display: flex; gap: 10px; justify-content: center; }

/* ---- 合作品牌 ---- */
.partner-grid {
    display: flex; flex-wrap: wrap; gap: 12px; justify-content: center;
}
.partner-item {
    background: var(--bg-card); border: 1px solid var(--border);
    color: var(--text-muted); padding: 12px 24px; border-radius: var(--radius);
    font-size: .85rem; transition: all var(--transition);
}
.partner-item:hover { border-color: var(--primary); color: var(--primary-light); }

/* ---- 步骤 ---- */
.howto-steps {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 20px;
}
.howto-step {
    background: var(--bg-dark); border: 1px solid var(--border);
    border-radius: var(--radius-lg); padding: 28px 22px; text-align: center;
}
.step-num {
    width: 48px; height: 48px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    border-radius: 50%; display: flex; align-items: center; justify-content: center;
    font-size: 1.2rem; font-weight: 900; color: #fff;
    margin: 0 auto 16px;
}
.howto-step h4 { font-size: .95rem; font-weight: 700; margin-bottom: 10px; }
.howto-step p { font-size: .82rem; color: var(--text-muted); line-height: 1.6; }

/* ---- 评价卡片 ---- */
.review-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}
.review-card {
    background: var(--bg-dark); border: 1px solid var(--border);
    border-radius: var(--radius-lg); padding: 24px;
    transition: all var(--transition);
}
.review-card:hover { border-color: var(--primary); }
.review-stars { color: var(--accent); font-size: 1rem; margin-bottom: 12px; }
.review-text {
    font-size: .85rem; color: var(--text-muted); line-height: 1.7;
    margin-bottom: 16px;
}
.review-user { display: flex; align-items: center; gap: 12px; }
.review-avatar {
    width: 38px; height: 38px; border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    display: flex; align-items: center; justify-content: center;
    font-size: .85rem; font-weight: 700; color: #fff; flex-shrink: 0;
}
.review-name { font-size: .85rem; font-weight: 600; }
.review-date { font-size: .75rem; color: var(--text-dim); }

/* ---- FAQ ---- */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
    border: 1px solid var(--border); border-radius: var(--radius);
    margin-bottom: 10px; overflow: hidden; transition: all var(--transition);
}
.faq-item.open { border-color: var(--primary); }
.faq-q {
    display: flex; justify-content: space-between; align-items: center;
    padding: 16px 20px; cursor: pointer; font-size: .9rem; font-weight: 600;
    color: var(--text-main); user-select: none;
}
.faq-q:hover { background: var(--bg-hover); }
.faq-icon { font-size: 1.2rem; color: var(--primary); transition: transform var(--transition); }
.faq-item.open .faq-icon { transform: rotate(45deg); }
.faq-a {
    max-height: 0; overflow: hidden;
    transition: max-height .35s ease, padding .35s ease;
    font-size: .85rem; color: var(--text-muted); line-height: 1.7;
    padding: 0 20px;
}
.faq-item.open .faq-a { max-height: 300px; padding: 0 20px 16px; }

/* ---- 联系卡片 ---- */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 20px;
}
.contact-card {
    background: var(--bg-dark); border: 1px solid var(--border);
    border-radius: var(--radius-lg); padding: 24px; text-align: center;
    transition: all var(--transition);
}
.contact-card:hover { border-color: var(--primary); transform: translateY(-3px); }
.contact-icon { font-size: 2rem; margin-bottom: 12px; }
.contact-card h4 { font-size: .95rem; font-weight: 700; margin-bottom: 8px; }
.contact-card p { font-size: .82rem; color: var(--text-muted); }
.qr-box { margin-top: 14px; }
.qr-box img {
    width: 100px; height: 100px; object-fit: cover;
    border-radius: var(--radius); margin: 0 auto;
    border: 1px solid var(--border);
}

/* ---- 图片Banner ---- */
.img-banner {
    position: relative; border-radius: var(--radius-lg); overflow: hidden;
    min-height: 280px;
}
.img-banner img {
    width: 100%; height: 320px; object-fit: cover;
    filter: brightness(.5);
}
.img-banner-text {
    position: absolute; inset: 0;
    display: flex; flex-direction: column; justify-content: center;
    padding: 40px; max-width: 560px;
}
.img-banner-text h2 { font-size: 1.6rem; font-weight: 800; margin-bottom: 12px; }
.img-banner-text p { color: var(--text-muted); font-size: .9rem; line-height: 1.7; }

/* ---- 标签 ---- */
.tag {
    display: inline-block;
    background: rgba(124,92,252,.15); border: 1px solid rgba(124,92,252,.3);
    color: var(--primary-light); font-size: .75rem;
    padding: 3px 10px; border-radius: 4px;
}

/* ---- 公告 ---- */
.notice {
    background: rgba(240,192,64,.08); border: 1px solid rgba(240,192,64,.3);
    color: var(--text-muted); border-radius: var(--radius);
    padding: 16px 20px; font-size: .85rem; line-height: 1.7;
}

/* ---- 面包屑 ---- */
.breadcrumb {
    display: flex; align-items: center; gap: 8px;
    font-size: .8rem; color: var(--text-dim);
    padding: 14px 0;
}
.breadcrumb a { color: var(--text-dim); }
.breadcrumb a:hover { color: var(--primary-light); }
.breadcrumb .sep { color: var(--text-dim); }
.breadcrumb .current { color: var(--text-muted); }

/* ---- 页面Hero ---- */
.page-hero {
    background: linear-gradient(135deg, var(--bg-card), #1a0a40);
    border-bottom: 1px solid var(--border);
    padding: 48px 0 40px;
}
.page-hero h1 {
    font-size: clamp(1.5rem, 4vw, 2.4rem);
    font-weight: 900; margin-bottom: 12px;
}
.page-hero p { color: var(--text-muted); font-size: .9rem; max-width: 560px; }

/* ---- 分类标签 ---- */
.cat-tabs {
    display: flex; flex-wrap: wrap; gap: 8px;
    margin-bottom: 28px;
}
.cat-tab {
    background: var(--bg-dark); border: 1px solid var(--border);
    color: var(--text-muted); padding: 7px 16px; border-radius: 8px;
    font-size: .82rem; transition: all var(--transition);
}
.cat-tab:hover, .cat-tab.active {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-color: transparent; color: #fff;
}

/* ---- 分享栏 ---- */
.share-section {
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    padding: 24px 0;
}
.share-title {
    text-align: center; color: var(--text-muted);
    font-size: .85rem; margin-bottom: 14px;
}
.share-bar { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.share-btn {
    display: inline-flex; align-items: center; gap: 8px;
    background: var(--bg-dark); border: 1px solid var(--border);
    color: var(--text-muted); padding: 8px 18px; border-radius: 8px;
    font-size: .82rem; transition: all var(--transition);
}
.share-btn:hover { border-color: var(--primary); color: var(--primary-light); }

/* ---- 页脚 ---- */
footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    padding: 48px 0 0;
}
.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 32px; margin-bottom: 40px;
}
.footer-brand .logo-text {
    font-size: 1.4rem; font-weight: 900;
    background: linear-gradient(135deg, var(--primary-light), var(--accent));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text; margin-bottom: 12px;
}
.footer-brand p { font-size: .82rem; color: var(--text-muted); line-height: 1.7; margin-bottom: 16px; }
.footer-qrs { display: flex; gap: 16px; }
.footer-qr { text-align: center; }
.footer-qr img {
    width: 80px; height: 80px; object-fit: cover;
    border-radius: var(--radius); border: 1px solid var(--border);
}
.footer-qr p { font-size: .72rem; color: var(--text-dim); margin-top: 4px; }
.footer-col h5 { font-size: .88rem; font-weight: 700; margin-bottom: 14px; color: var(--text-main); }
.footer-col ul li { margin-bottom: 8px; }
.footer-col ul li a { font-size: .82rem; color: var(--text-muted); transition: color var(--transition); }
.footer-col ul li a:hover { color: var(--primary-light); }
.footer-bottom {
    border-top: 1px solid var(--border);
    padding: 20px 0;
    display: flex; justify-content: space-between; align-items: flex-start;
    flex-wrap: wrap; gap: 16px; font-size: .78rem; color: var(--text-dim);
}
.footer-bottom a { color: var(--text-dim); margin: 0 8px; }
.footer-bottom a:hover { color: var(--primary-light); }
.update-time { color: var(--text-dim); font-size: .75rem; margin-top: 4px; }

/* ---- 弹窗 ---- */
.modal-overlay {
    position: fixed; inset: 0; z-index: 9999;
    background: rgba(0,0,0,.88); backdrop-filter: blur(8px);
    display: flex; align-items: center; justify-content: center;
    opacity: 0; pointer-events: none; transition: opacity var(--transition);
}
.modal-overlay.open { opacity: 1; pointer-events: auto; }
.modal-box {
    background: var(--bg-card); border: 1px solid var(--border);
    border-radius: var(--radius-xl); padding: 28px;
    max-width: 560px; width: calc(100% - 32px);
    transform: scale(.95); transition: transform var(--transition);
}
.modal-overlay.open .modal-box { transform: scale(1); }
.modal-close {
    float: right; font-size: 1.4rem; color: var(--text-muted);
    line-height: 1; margin-bottom: 8px;
}
.modal-close:hover { color: var(--danger); }
.modal-video-placeholder {
    background: var(--bg-dark); border-radius: var(--radius);
    aspect-ratio: 16/9; display: flex; align-items: center; justify-content: center;
    color: var(--text-muted); font-size: .88rem; margin-bottom: 16px;
    border: 1px solid var(--border);
}

/* ---- 返回顶部 ---- */
.back-to-top {
    position: fixed; bottom: 32px; right: 28px; z-index: 999;
    width: 44px; height: 44px; border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff; font-size: 1.2rem; font-weight: 700;
    display: flex; align-items: center; justify-content: center;
    box-shadow: 0 4px 20px rgba(124,92,252,.4);
    opacity: 0; pointer-events: none;
    transition: opacity var(--transition), transform var(--transition);
    border: none; cursor: pointer;
}
.back-to-top.visible { opacity: 1; pointer-events: auto; }
.back-to-top:hover { transform: translateY(-3px); }

/* ---- 动画 ---- */
.fade-in-up {
    animation: fadeInUp .8s ease both;
}
.delay-1 { animation-delay: .1s; }
.delay-2 { animation-delay: .2s; }
.delay-3 { animation-delay: .3s; }
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(24px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ---- 内容文章区 ---- */
.article-body {
    font-size: .9rem; color: var(--text-muted); line-height: 1.9;
}
.article-body h3 { font-size: 1.05rem; font-weight: 700; color: var(--text-main); margin: 24px 0 10px; }
.article-body p  { margin-bottom: 14px; }
.article-body ul { padding-left: 20px; list-style: disc; margin-bottom: 14px; }
.article-body ul li { margin-bottom: 6px; }

/* =============================================
   响应式适配
   ============================================= */
@media (max-width: 1024px) {
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .hero-stats { gap: 20px; }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none; position: absolute; top: 62px; left: 0; right: 0;
        background: rgba(10,11,20,.98); flex-direction: column;
        padding: 16px 20px; border-bottom: 1px solid var(--border);
        gap: 4px;
    }
    .nav-menu.open { display: flex; }
    .nav-menu a { padding: 10px 14px; }
    .nav-toggle { display: flex; }
    .navbar { position: relative; }

    .hero { min-height: 420px; padding: 40px 0; }
    .hero h1 { font-size: 1.8rem; }
    .hero-stats { gap: 16px; }
    .hero-stat .num { font-size: 1.2rem; }

    .section { padding: 40px 0; }
    .section-title { font-size: 1.4rem; }

    .video-grid { grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 14px; }
    .video-grid-vertical { grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 12px; }
    .feature-grid { grid-template-columns: 1fr 1fr; gap: 14px; }
    .expert-grid { grid-template-columns: 1fr; }
    .review-grid { grid-template-columns: 1fr; }
    .howto-steps { grid-template-columns: 1fr 1fr; }
    .contact-grid { grid-template-columns: 1fr 1fr; }

    .footer-grid { grid-template-columns: 1fr 1fr; gap: 24px; }
    .footer-bottom { flex-direction: column; }

    .img-banner img { height: 220px; }
    .img-banner-text { padding: 24px; }
    .img-banner-text h2 { font-size: 1.2rem; }

    .stats-row { gap: 12px; }
    .stat-item { min-width: 100px; padding: 16px 10px; }
    .stat-num { font-size: 1.5rem; }
}

@media (max-width: 480px) {
    .hero h1 { font-size: 1.5rem; }
    .hero-btns { flex-direction: column; }
    .hero-stats { gap: 12px; }

    .feature-grid { grid-template-columns: 1fr; }
    .howto-steps { grid-template-columns: 1fr; }
    .contact-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; }

    .video-grid { grid-template-columns: 1fr 1fr; }
    .video-grid-vertical { grid-template-columns: repeat(3, 1fr); }
    .cat-tabs { gap: 6px; }
    .cat-tab { padding: 5px 12px; font-size: .78rem; }

    .search-bar-inner { flex-direction: column; }
    .search-btn { width: 100%; }

    .back-to-top { bottom: 20px; right: 16px; width: 38px; height: 38px; font-size: 1rem; }
}

/* ---- 打印样式 ---- */
@media print {
    .navbar, .top-bar, .search-bar-wrap, footer, .modal-overlay,
    .share-section, .back-to-top { display: none; }
    body { background: #fff; color: #000; }
    a { color: #000; }
}