/* ========================================
   抖阴 - 原创样式表
   品牌色系：珊瑚粉 #FF6B6B / 暖橙 #FF8E53 / 深灰 #1A1A2E / 浅灰 #F5F5F7
   ======================================== */

/* CSS Reset & Base */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body { font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif; color: #333; background: #F5F5F7; line-height: 1.7; overflow-x: hidden; }
a { text-decoration: none; color: inherit; transition: color .3s; }
a:hover { color: #FF6B6B; }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ---- 顶部导航 ---- */
.site-header { background: #1A1A2E; position: sticky; top: 0; z-index: 1000; box-shadow: 0 2px 20px rgba(0,0,0,.3); }
.nav-wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.nav-logo { display: flex; align-items: center; gap: 10px; }
.nav-logo img { height: 40px; width: auto; }
.nav-logo span { color: #fff; font-size: 1.2rem; font-weight: 700; }
.nav-menu { display: flex; gap: 6px; }
.nav-menu a { color: #ddd; padding: 8px 14px; border-radius: 6px; font-size: .9rem; transition: all .3s; white-space: nowrap; }
.nav-menu a:hover, .nav-menu a.active { background: linear-gradient(135deg, #FF6B6B, #FF8E53); color: #fff; }
.nav-toggle { display: none; color: #fff; font-size: 1.5rem; cursor: pointer; background: none; border: none; }

/* ---- 搜索框 ---- */
.search-bar { background: linear-gradient(135deg, #1A1A2E 0%, #16213E 100%); padding: 14px 0; border-bottom: 1px solid rgba(255,255,255,.05); }
.search-inner { display: flex; justify-content: center; align-items: center; gap: 10px; }
.search-inner input { width: 460px; max-width: 70%; padding: 10px 20px; border: 2px solid rgba(255,107,107,.4); border-radius: 30px; background: rgba(255,255,255,.08); color: #fff; font-size: .95rem; outline: none; transition: border-color .3s; }
.search-inner input::placeholder { color: rgba(255,255,255,.4); }
.search-inner input:focus { border-color: #FF6B6B; }
.search-inner button { padding: 10px 28px; background: linear-gradient(135deg, #FF6B6B, #FF8E53); color: #fff; border: none; border-radius: 30px; font-size: .95rem; cursor: pointer; transition: transform .2s, box-shadow .3s; }
.search-inner button:hover { transform: scale(1.05); box-shadow: 0 4px 15px rgba(255,107,107,.4); }

/* ---- Hero Banner ---- */
.hero-banner { position: relative; height: 520px; overflow: hidden; }
.hero-slide { position: absolute; inset: 0; opacity: 0; transition: opacity 1s ease-in-out; }
.hero-slide.active { opacity: 1; }
.hero-slide img { width: 100%; height: 100%; object-fit: cover; }
.hero-overlay { position: absolute; inset: 0; background: linear-gradient(135deg, rgba(26,26,46,.85) 0%, rgba(26,26,46,.4) 100%); display: flex; align-items: center; }
.hero-content { padding: 0 60px; max-width: 650px; }
.hero-content h1 { font-size: 2.6rem; color: #fff; margin-bottom: 16px; line-height: 1.3; }
.hero-content h1 span { background: linear-gradient(135deg, #FF6B6B, #FF8E53); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.hero-content p { color: rgba(255,255,255,.8); font-size: 1.1rem; margin-bottom: 28px; }
.btn-primary { display: inline-block; padding: 12px 36px; background: linear-gradient(135deg, #FF6B6B, #FF8E53); color: #fff; border-radius: 30px; font-size: 1rem; font-weight: 600; transition: transform .2s, box-shadow .3s; border: none; cursor: pointer; }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 25px rgba(255,107,107,.4); color: #fff; }
.btn-outline { display: inline-block; padding: 12px 36px; border: 2px solid #FF6B6B; color: #FF6B6B; border-radius: 30px; font-size: 1rem; font-weight: 600; transition: all .3s; margin-left: 12px; }
.btn-outline:hover { background: #FF6B6B; color: #fff; }

/* ---- 通用区块 ---- */
.section { padding: 60px 0; }
.section-dark { background: #1A1A2E; color: #fff; }
.section-gradient { background: linear-gradient(180deg, #F5F5F7 0%, #fff 100%); }
.section-title { text-align: center; margin-bottom: 40px; }
.section-title h2 { font-size: 2rem; color: #1A1A2E; margin-bottom: 10px; }
.section-dark .section-title h2 { color: #fff; }
.section-title p { color: #666; font-size: 1rem; }
.section-dark .section-title p { color: rgba(255,255,255,.6); }
.section-title .highlight { color: #FF6B6B; }

/* ---- 视频卡片网格 ---- */
.video-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.video-card { background: #fff; border-radius: 12px; overflow: hidden; box-shadow: 0 4px 20px rgba(0,0,0,.06); transition: transform .3s, box-shadow .3s; cursor: pointer; }
.video-card:hover { transform: translateY(-6px); box-shadow: 0 12px 40px rgba(0,0,0,.12); }
.video-card .thumb { position: relative; padding-top: 56.25%; overflow: hidden; }
.video-card .thumb img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; transition: transform .5s; }
.video-card:hover .thumb img { transform: scale(1.08); }
.video-card .play-icon { position: absolute; top: 50%; left: 50%; transform: translate(-50%,-50%); width: 48px; height: 48px; background: rgba(255,107,107,.9); border-radius: 50%; display: flex; align-items: center; justify-content: center; opacity: 0; transition: opacity .3s; }
.video-card:hover .play-icon { opacity: 1; }
.play-icon::after { content: ''; border-left: 16px solid #fff; border-top: 10px solid transparent; border-bottom: 10px solid transparent; margin-left: 3px; }
.video-card .card-body { padding: 14px 16px; }
.video-card .card-title { font-size: .95rem; font-weight: 600; color: #1A1A2E; margin-bottom: 8px; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.video-card .card-meta { display: flex; justify-content: space-between; align-items: center; font-size: .8rem; color: #999; }
.video-card .card-tags { display: flex; gap: 6px; margin-top: 8px; flex-wrap: wrap; }
.video-card .tag { padding: 2px 10px; background: linear-gradient(135deg, rgba(255,107,107,.1), rgba(255,142,83,.1)); color: #FF6B6B; border-radius: 12px; font-size: .75rem; }

/* ---- 分类导航条 ---- */
.category-tabs { display: flex; justify-content: center; gap: 12px; margin-bottom: 30px; flex-wrap: wrap; }
.category-tabs .tab { padding: 8px 22px; border-radius: 20px; background: #fff; color: #666; font-size: .9rem; cursor: pointer; transition: all .3s; border: 1px solid #eee; }
.category-tabs .tab:hover, .category-tabs .tab.active { background: linear-gradient(135deg, #FF6B6B, #FF8E53); color: #fff; border-color: transparent; }

/* ---- 专家卡片 ---- */
.expert-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.expert-card { background: #fff; border-radius: 16px; padding: 30px 20px; text-align: center; box-shadow: 0 4px 20px rgba(0,0,0,.06); transition: transform .3s; }
.expert-card:hover { transform: translateY(-4px); }
.expert-card .avatar { width: 100px; height: 100px; border-radius: 50%; margin: 0 auto 16px; object-fit: cover; border: 3px solid #FF6B6B; }
.expert-card h4 { font-size: 1.1rem; color: #1A1A2E; margin-bottom: 4px; }
.expert-card .role { color: #FF6B6B; font-size: .85rem; margin-bottom: 10px; }
.expert-card p { font-size: .85rem; color: #666; margin-bottom: 14px; }
.expert-card .btn-sm { padding: 6px 20px; font-size: .8rem; border-radius: 20px; }

/* ---- FAQ 手风琴 ---- */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item { background: #fff; border-radius: 12px; margin-bottom: 12px; overflow: hidden; box-shadow: 0 2px 10px rgba(0,0,0,.04); }
.faq-item .faq-q { padding: 18px 24px; font-size: 1rem; font-weight: 600; color: #1A1A2E; cursor: pointer; display: flex; justify-content: space-between; align-items: center; transition: background .3s; }
.faq-item .faq-q:hover { background: rgba(255,107,107,.05); }
.faq-item .faq-q::after { content: '+'; font-size: 1.4rem; color: #FF6B6B; transition: transform .3s; }
.faq-item.open .faq-q::after { transform: rotate(45deg); }
.faq-item .faq-a { max-height: 0; overflow: hidden; transition: max-height .4s ease, padding .4s; padding: 0 24px; color: #666; font-size: .9rem; line-height: 1.8; }
.faq-item.open .faq-a { max-height: 300px; padding: 0 24px 18px; }

/* ---- 用户评论 ---- */
.review-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.review-card { background: #fff; border-radius: 12px; padding: 24px; box-shadow: 0 4px 15px rgba(0,0,0,.05); }
.review-card .stars { color: #FF8E53; font-size: 1rem; margin-bottom: 10px; }
.review-card .review-text { font-size: .9rem; color: #555; margin-bottom: 14px; line-height: 1.7; }
.review-card .reviewer { display: flex; align-items: center; gap: 10px; }
.review-card .reviewer-avatar { width: 36px; height: 36px; border-radius: 50%; background: linear-gradient(135deg, #FF6B6B, #FF8E53); display: flex; align-items: center; justify-content: center; color: #fff; font-size: .85rem; font-weight: 700; }
.review-card .reviewer-name { font-size: .85rem; color: #333; font-weight: 600; }
.review-card .reviewer-date { font-size: .75rem; color: #999; }

/* ---- 合作品牌墙 ---- */
.partner-wall { display: flex; justify-content: center; align-items: center; gap: 40px; flex-wrap: wrap; padding: 20px 0; }
.partner-wall .partner-item { width: 120px; height: 60px; background: #fff; border-radius: 10px; display: flex; align-items: center; justify-content: center; box-shadow: 0 2px 10px rgba(0,0,0,.06); padding: 10px; font-size: .85rem; color: #999; font-weight: 600; }

/* ---- 联系我们 ---- */
.contact-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.contact-card { background: #fff; border-radius: 12px; padding: 30px; text-align: center; box-shadow: 0 4px 15px rgba(0,0,0,.05); }
.contact-card .icon { width: 50px; height: 50px; background: linear-gradient(135deg, #FF6B6B, #FF8E53); border-radius: 50%; display: flex; align-items: center; justify-content: center; margin: 0 auto 14px; color: #fff; font-size: 1.2rem; }
.contact-card h4 { font-size: 1rem; color: #1A1A2E; margin-bottom: 8px; }
.contact-card p { font-size: .85rem; color: #666; }

/* ---- 社交分享 ---- */
.share-bar { display: flex; justify-content: center; gap: 16px; padding: 20px 0; }
.share-btn { width: 44px; height: 44px; border-radius: 50%; display: flex; align-items: center; justify-content: center; color: #fff; font-size: 1.1rem; transition: transform .2s; cursor: pointer; }
.share-btn:hover { transform: scale(1.15); }
.share-btn.wechat { background: #07C160; }
.share-btn.weibo { background: #E6162D; }
.share-btn.douyin { background: #161823; }
.share-btn.bilibili { background: #00A1D6; }

/* ---- 页脚 ---- */
.site-footer { background: #0F0F23; color: rgba(255,255,255,.6); padding: 50px 0 20px; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 30px; margin-bottom: 30px; }
.footer-col h4 { color: #fff; font-size: 1rem; margin-bottom: 16px; position: relative; padding-bottom: 10px; }
.footer-col h4::after { content: ''; position: absolute; bottom: 0; left: 0; width: 30px; height: 2px; background: linear-gradient(135deg, #FF6B6B, #FF8E53); }
.footer-col p, .footer-col a { font-size: .85rem; line-height: 2; display: block; }
.footer-col a:hover { color: #FF6B6B; }
.footer-logo { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.footer-logo img { height: 36px; }
.footer-logo span { color: #fff; font-size: 1.1rem; font-weight: 700; }
.footer-qr { display: flex; gap: 16px; margin-top: 14px; }
.footer-qr img { width: 100px; height: 100px; border-radius: 8px; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.08); padding-top: 20px; text-align: center; font-size: .8rem; }

/* ---- 面包屑 ---- */
.breadcrumb { padding: 14px 0; font-size: .85rem; color: #999; }
.breadcrumb a { color: #FF6B6B; }
.breadcrumb span { margin: 0 6px; }

/* ---- 内页视频播放 ---- */
.video-player-wrap { position: relative; padding-top: 56.25%; background: #000; border-radius: 12px; overflow: hidden; margin-bottom: 24px; }
.video-player-wrap iframe, .video-player-wrap video { position: absolute; inset: 0; width: 100%; height: 100%; }

/* ---- 内页侧边栏 ---- */
.page-layout { display: grid; grid-template-columns: 1fr 340px; gap: 30px; }
.sidebar .widget { background: #fff; border-radius: 12px; padding: 20px; margin-bottom: 20px; box-shadow: 0 4px 15px rgba(0,0,0,.05); }
.sidebar .widget h4 { font-size: 1rem; color: #1A1A2E; margin-bottom: 14px; padding-bottom: 10px; border-bottom: 2px solid #FF6B6B; }
.sidebar .widget-list a { display: flex; gap: 12px; padding: 10px 0; border-bottom: 1px solid #f0f0f0; }
.sidebar .widget-list a:last-child { border-bottom: none; }
.sidebar .widget-list .mini-thumb { width: 80px; height: 50px; border-radius: 6px; object-fit: cover; flex-shrink: 0; }
.sidebar .widget-list .mini-title { font-size: .85rem; color: #333; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }

/* ---- How-To 指南 ---- */
.howto-steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; counter-reset: step; }
.howto-step { background: #fff; border-radius: 12px; padding: 28px 20px; text-align: center; box-shadow: 0 4px 15px rgba(0,0,0,.05); position: relative; }
.howto-step::before { counter-increment: step; content: counter(step); width: 36px; height: 36px; background: linear-gradient(135deg, #FF6B6B, #FF8E53); color: #fff; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: 700; margin: 0 auto 14px; }
.howto-step h4 { font-size: .95rem; color: #1A1A2E; margin-bottom: 8px; }
.howto-step p { font-size: .85rem; color: #666; }

/* ---- 数据统计条 ---- */
.stats-bar { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; padding: 40px 0; }
.stat-item { text-align: center; }
.stat-item .num { font-size: 2.4rem; font-weight: 800; background: linear-gradient(135deg, #FF6B6B, #FF8E53); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.stat-item .label { font-size: .9rem; color: rgba(255,255,255,.6); margin-top: 4px; }

/* ---- 图片懒加载占位 ---- */
img[loading="lazy"] { background: #eee; }

/* ---- 响应式 ---- */
@media (max-width: 1024px) {
  .video-grid { grid-template-columns: repeat(3, 1fr); }
  .expert-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .page-layout { grid-template-columns: 1fr; }
  .howto-steps { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .nav-menu { display: none; position: fixed; top: 64px; left: 0; right: 0; background: #1A1A2E; flex-direction: column; padding: 20px; gap: 4px; z-index: 999; }
  .nav-menu.open { display: flex; }
  .nav-toggle { display: block; }
  .hero-banner { height: 380px; }
  .hero-content { padding: 0 24px; }
  .hero-content h1 { font-size: 1.8rem; }
  .video-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .review-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .stats-bar { grid-template-columns: repeat(2, 1fr); }
  .search-inner input { width: 100%; max-width: 60%; }
  .footer-grid { grid-template-columns: 1fr; }
}
@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
  .expert-grid { grid-template-columns: 1fr; }
  .howto-steps { grid-template-columns: 1fr; }
}