/* ============================================
   51视频 - 原创样式表
   品牌色系：活力橙 #FF6B35 / 深邃蓝黑 #1A1A2E / 樱红 #E94560
   ============================================ */

/* === 基础重置 === */
*, *::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;
  background-color: #0F0F23;
  color: #EAEAEA;
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: #FF6B35; text-decoration: none; transition: color .3s; }
a:hover { color: #E94560; }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* === 头部导航 === */
.site-header {
  position: fixed; top: 0; left: 0; width: 100%; z-index: 1000;
  background: rgba(15, 15, 35, .92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 107, 53, .15);
  transition: background .3s;
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  max-width: 1200px; margin: 0 auto; padding: 0 20px; height: 68px;
}
.site-logo { display: flex; align-items: center; gap: 10px; }
.site-logo img { height: 42px; width: auto; }
.site-logo span { font-size: 1.4rem; font-weight: 700; background: linear-gradient(135deg, #FF6B35, #E94560); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }

.main-nav { display: flex; align-items: center; gap: 6px; }
.main-nav a {
  padding: 8px 16px; border-radius: 8px; font-size: .95rem; color: #EAEAEA;
  transition: all .3s; position: relative;
}
.main-nav a:hover, .main-nav a.active {
  color: #FF6B35; background: rgba(255, 107, 53, .1);
}
.nav-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 8px; }
.nav-toggle span { width: 24px; height: 2px; background: #EAEAEA; transition: .3s; border-radius: 2px; }

/* === 搜索框 === */
.search-bar {
  background: rgba(22, 33, 62, .8); border-bottom: 1px solid rgba(255, 107, 53, .1);
  padding: 12px 0; margin-top: 68px;
}
.search-bar .container { display: flex; justify-content: center; }
.search-wrap {
  display: flex; width: 100%; max-width: 600px;
  border-radius: 30px; overflow: hidden;
  border: 2px solid rgba(255, 107, 53, .3);
  transition: border-color .3s;
}
.search-wrap:focus-within { border-color: #FF6B35; }
.search-wrap input {
  flex: 1; padding: 12px 20px; background: rgba(15, 15, 35, .6);
  border: none; color: #EAEAEA; font-size: .95rem; outline: none;
}
.search-wrap input::placeholder { color: #666; }
.search-wrap button {
  padding: 12px 28px; background: linear-gradient(135deg, #FF6B35, #E94560);
  border: none; color: #fff; font-size: .95rem; cursor: pointer;
  transition: opacity .3s;
}
.search-wrap button:hover { opacity: .85; }

/* === Hero Banner === */
.hero-section {
  position: relative; min-height: 520px; display: flex; align-items: center;
  background-size: cover; background-position: center; background-repeat: no-repeat;
  overflow: hidden;
}
.hero-overlay {
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(15,15,35,.5) 0%, rgba(15,15,35,.85) 100%);
}
.hero-content {
  position: relative; z-index: 2; text-align: center; width: 100%; padding: 60px 20px;
}
.hero-content h1 {
  font-size: 2.8rem; font-weight: 800; margin-bottom: 16px;
  background: linear-gradient(135deg, #FF6B35, #E94560);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  line-height: 1.3;
}
.hero-content p { font-size: 1.15rem; color: #ccc; max-width: 680px; margin: 0 auto 30px; }
.hero-tags { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin-top: 20px; }
.hero-tags span {
  padding: 6px 16px; border-radius: 20px; font-size: .85rem;
  background: rgba(255, 107, 53, .12); border: 1px solid rgba(255, 107, 53, .3); color: #FF6B35;
}

/* === 通用按钮 === */
.btn-primary {
  display: inline-block; padding: 12px 32px; border-radius: 30px;
  background: linear-gradient(135deg, #FF6B35, #E94560);
  color: #fff; font-size: 1rem; font-weight: 600; border: none; cursor: pointer;
  transition: transform .3s, box-shadow .3s;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 25px rgba(233, 69, 96, .3); color: #fff; }
.btn-outline {
  display: inline-block; padding: 10px 28px; border-radius: 30px;
  border: 2px solid #FF6B35; color: #FF6B35; font-size: .95rem; transition: all .3s;
}
.btn-outline:hover { background: #FF6B35; color: #fff; }

/* === 通用区块 === */
.section { padding: 70px 0; }
.section-dark { background: #0F0F23; }
.section-alt { background: #0D0D1F; }
.section-header { text-align: center; margin-bottom: 50px; }
.section-header h2 {
  font-size: 2rem; font-weight: 700; margin-bottom: 12px;
  background: linear-gradient(135deg, #FF6B35, #E94560);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.section-header p { color: #999; font-size: 1rem; max-width: 600px; margin: 0 auto; }

/* === 动漫视频卡片 === */
.video-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.video-card {
  border-radius: 14px; overflow: hidden; background: #16213E;
  transition: transform .3s, box-shadow .3s; cursor: pointer;
}
.video-card:hover { transform: translateY(-6px); box-shadow: 0 12px 35px rgba(255, 107, 53, .15); }
.video-thumb {
  position: relative; padding-top: 56.25%; overflow: hidden;
}
.video-thumb img {
  position: absolute; top: 0; left: 0; width: 100%; height: 100%; object-fit: cover;
  transition: transform .5s;
}
.video-card:hover .video-thumb img { transform: scale(1.08); }
.play-btn {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%);
  width: 60px; height: 60px; border-radius: 50%;
  background: rgba(255, 107, 53, .85); display: flex; align-items: center; justify-content: center;
  opacity: 0; transition: opacity .3s, transform .3s;
}
.play-btn::after {
  content: ''; width: 0; height: 0;
  border-left: 20px solid #fff; border-top: 12px solid transparent; border-bottom: 12px solid transparent;
  margin-left: 4px;
}
.video-card:hover .play-btn { opacity: 1; transform: translate(-50%, -50%) scale(1.05); }
.video-info { padding: 16px; }
.video-info h3 { font-size: 1rem; font-weight: 600; margin-bottom: 8px; color: #EAEAEA; line-height: 1.4; }
.video-meta { display: flex; gap: 14px; font-size: .82rem; color: #888; }
.video-meta span { display: flex; align-items: center; gap: 4px; }
.video-tag {
  display: inline-block; padding: 3px 10px; border-radius: 12px; font-size: .75rem;
  background: rgba(233, 69, 96, .12); color: #E94560; margin-top: 8px;
}

/* === 服务模块 === */
.service-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.service-card {
  padding: 36px 28px; border-radius: 16px; background: #16213E;
  border: 1px solid rgba(255, 107, 53, .08); transition: all .3s; text-align: center;
}
.service-card:hover { border-color: rgba(255, 107, 53, .3); transform: translateY(-4px); }
.service-icon {
  width: 64px; height: 64px; margin: 0 auto 20px;
  border-radius: 16px; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, rgba(255,107,53,.15), rgba(233,69,96,.15));
  font-size: 1.8rem;
}
.service-card h3 { font-size: 1.15rem; margin-bottom: 10px; color: #EAEAEA; }
.service-card p { font-size: .9rem; color: #999; line-height: 1.6; }

/* === AI赋能区 === */
.ai-section {
  position: relative; background-size: cover; background-position: center;
  padding: 80px 0;
}
.ai-overlay {
  position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(15,15,35,.9), rgba(22,33,62,.85));
}
.ai-content { position: relative; z-index: 2; }
.ai-features { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; margin-top: 40px; }
.ai-feature-card {
  padding: 28px; border-radius: 14px;
  background: rgba(22, 33, 62, .7); border: 1px solid rgba(255, 107, 53, .1);
  backdrop-filter: blur(8px); transition: all .3s;
}
.ai-feature-card:hover { border-color: rgba(255, 107, 53, .4); }
.ai-feature-card h4 { font-size: 1.1rem; color: #FF6B35; margin-bottom: 10px; }
.ai-feature-card p { font-size: .9rem; color: #bbb; }

/* === 社区功能 === */
.community-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.community-item {
  padding: 28px 20px; border-radius: 14px; background: #16213E;
  text-align: center; transition: all .3s;
  border: 1px solid rgba(233, 69, 96, .08);
}
.community-item:hover { border-color: rgba(233, 69, 96, .3); transform: translateY(-4px); }
.community-item .icon { font-size: 2.2rem; margin-bottom: 14px; }
.community-item h4 { font-size: 1rem; margin-bottom: 8px; color: #EAEAEA; }
.community-item p { font-size: .85rem; color: #999; }

/* === 专家展示 === */
.expert-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.expert-card {
  border-radius: 16px; overflow: hidden; background: #16213E;
  border: 1px solid rgba(255, 107, 53, .08); transition: all .3s;
}
.expert-card:hover { border-color: rgba(255, 107, 53, .3); }
.expert-avatar { width: 100%; aspect-ratio: 1; object-fit: cover; }
.expert-info { padding: 20px; text-align: center; }
.expert-info h4 { font-size: 1.1rem; margin-bottom: 4px; color: #EAEAEA; }
.expert-info .role { font-size: .85rem; color: #FF6B35; margin-bottom: 10px; }
.expert-info p { font-size: .85rem; color: #999; margin-bottom: 14px; }
.expert-links { display: flex; justify-content: center; gap: 10px; }
.expert-links a {
  padding: 6px 16px; border-radius: 20px; font-size: .82rem;
  border: 1px solid rgba(255, 107, 53, .3); color: #FF6B35; transition: all .3s;
}
.expert-links a:hover { background: #FF6B35; color: #fff; }

/* === 合作品牌墙 === */
.brand-wall {
  display: flex; flex-wrap: wrap; justify-content: center; gap: 30px;
  padding: 30px 0;
}
.brand-item {
  width: 140px; height: 70px; border-radius: 10px;
  background: rgba(22, 33, 62, .6); border: 1px solid rgba(255, 107, 53, .1);
  display: flex; align-items: center; justify-content: center;
  font-size: .9rem; color: #888; transition: all .3s;
}
.brand-item:hover { border-color: #FF6B35; color: #FF6B35; }

/* === FAQ === */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  margin-bottom: 12px; border-radius: 12px; overflow: hidden;
  background: #16213E; border: 1px solid rgba(255, 107, 53, .08);
}
.faq-question {
  padding: 18px 24px; cursor: pointer; display: flex;
  justify-content: space-between; align-items: center;
  font-size: 1rem; font-weight: 600; color: #EAEAEA; transition: color .3s;
}
.faq-question:hover { color: #FF6B35; }
.faq-question::after { content: '+'; font-size: 1.4rem; color: #FF6B35; transition: transform .3s; }
.faq-item.active .faq-question::after { transform: rotate(45deg); }
.faq-answer {
  max-height: 0; overflow: hidden; transition: max-height .4s ease, padding .4s;
  padding: 0 24px; font-size: .9rem; color: #bbb; line-height: 1.7;
}
.faq-item.active .faq-answer { max-height: 300px; padding: 0 24px 18px; }

/* === 用户评论 === */
.review-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.review-card {
  padding: 28px; border-radius: 14px; background: #16213E;
  border: 1px solid rgba(233, 69, 96, .08); transition: all .3s;
}
.review-card:hover { border-color: rgba(233, 69, 96, .25); }
.review-stars { color: #FF6B35; font-size: 1rem; margin-bottom: 12px; letter-spacing: 2px; }
.review-text { font-size: .92rem; color: #ccc; margin-bottom: 14px; line-height: 1.7; font-style: italic; }
.review-author { display: flex; align-items: center; gap: 10px; }
.review-avatar {
  width: 40px; height: 40px; border-radius: 50%;
  background: linear-gradient(135deg, #FF6B35, #E94560);
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 700; font-size: .9rem;
}
.review-author-info .name { font-size: .9rem; color: #EAEAEA; font-weight: 600; }
.review-author-info .date { font-size: .78rem; color: #888; }

/* === 联系我们 === */
.contact-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 40px; align-items: start; }
.contact-info-list { display: flex; flex-direction: column; gap: 20px; }
.contact-item {
  display: flex; gap: 16px; padding: 20px; border-radius: 12px;
  background: #16213E; border: 1px solid rgba(255, 107, 53, .08);
}
.contact-item .icon {
  width: 48px; height: 48px; border-radius: 12px; flex-shrink: 0;
  background: linear-gradient(135deg, rgba(255,107,53,.15), rgba(233,69,96,.15));
  display: flex; align-items: center; justify-content: center; font-size: 1.3rem;
}
.contact-item h4 { font-size: .95rem; color: #EAEAEA; margin-bottom: 4px; }
.contact-item p { font-size: .85rem; color: #999; }
.qrcode-area { display: flex; gap: 30px; justify-content: center; }
.qrcode-box { text-align: center; }
.qrcode-box img { width: 160px; height: 160px; border-radius: 12px; margin-bottom: 10px; }
.qrcode-box p { font-size: .85rem; color: #999; }

/* === 分享按钮 === */
.share-bar { display: flex; gap: 12px; justify-content: center; padding: 20px 0; }
.share-btn {
  width: 44px; height: 44px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: .85rem; font-weight: 700; color: #fff; transition: all .3s; cursor: pointer;
}
.share-btn:hover { transform: translateY(-3px); }
.share-wechat { background: #07C160; }
.share-weibo { background: #E6162D; }
.share-douyin { background: #161823; border: 1px solid #333; }
.share-bilibili { background: #00A1D6; }

/* === 页脚 === */
.site-footer {
  background: #0A0A1A; border-top: 1px solid rgba(255, 107, 53, .1);
  padding: 50px 0 20px;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px;
  margin-bottom: 40px;
}
.footer-brand p { font-size: .88rem; color: #888; margin-top: 14px; line-height: 1.7; }
.footer-col h4 {
  font-size: 1rem; color: #EAEAEA; margin-bottom: 16px;
  padding-bottom: 8px; border-bottom: 2px solid #FF6B35; display: inline-block;
}
.footer-col a { display: block; padding: 4px 0; font-size: .88rem; color: #888; transition: color .3s; }
.footer-col a:hover { color: #FF6B35; }
.footer-bottom {
  text-align: center; padding-top: 20px;
  border-top: 1px solid rgba(255, 107, 53, .08);
  font-size: .82rem; color: #666;
}
.footer-bottom a { color: #888; }

/* === 面包屑 === */
.breadcrumb {
  padding: 14px 0; font-size: .85rem; color: #888;
}
.breadcrumb a { color: #FF6B35; }
.breadcrumb span { margin: 0 8px; color: #555; }

/* === How-To 指南 === */
.howto-steps { max-width: 700px; margin: 0 auto; }
.howto-step {
  display: flex; gap: 20px; margin-bottom: 28px; align-items: flex-start;
}
.step-num {
  width: 44px; height: 44px; border-radius: 50%; flex-shrink: 0;
  background: linear-gradient(135deg, #FF6B35, #E94560);
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 700; font-size: 1.1rem;
}
.step-content h4 { font-size: 1rem; color: #EAEAEA; margin-bottom: 6px; }
.step-content p { font-size: .9rem; color: #999; }

/* === 内页通用 === */
.page-hero {
  padding: 100px 0 50px; text-align: center;
  background: linear-gradient(180deg, #16213E 0%, #0F0F23 100%);
}
.page-hero h1 {
  font-size: 2.2rem; font-weight: 700;
  background: linear-gradient(135deg, #FF6B35, #E94560);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  margin-bottom: 12px;
}
.page-hero p { color: #999; font-size: 1rem; }

/* === 标签云 === */
.tag-cloud { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-top: 20px; }
.tag-cloud a {
  padding: 5px 14px; border-radius: 16px; font-size: .82rem;
  background: rgba(255, 107, 53, .08); color: #FF6B35;
  border: 1px solid rgba(255, 107, 53, .15); transition: all .3s;
}
.tag-cloud a:hover { background: #FF6B35; color: #fff; }

/* === 数据统计条 === */
.stats-bar {
  display: flex; justify-content: center; gap: 50px; padding: 40px 0;
  background: linear-gradient(135deg, rgba(255,107,53,.06), rgba(233,69,96,.06));
  border-radius: 16px; margin: 30px 0;
}
.stat-item { text-align: center; }
.stat-num {
  font-size: 2rem; font-weight: 800;
  background: linear-gradient(135deg, #FF6B35, #E94560);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.stat-label { font-size: .85rem; color: #999; margin-top: 4px; }

/* === 响应式 === */
@media (max-width: 1024px) {
  .video-grid { grid-template-columns: repeat(2, 1fr); }
  .service-grid { grid-template-columns: repeat(2, 1fr); }
  .community-grid { grid-template-columns: repeat(2, 1fr); }
  .expert-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .ai-features { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .main-nav {
    position: fixed; top: 68px; left: 0; width: 100%;
    flex-direction: column; background: rgba(15, 15, 35, .98);
    padding: 20px; gap: 4px; transform: translateY(-120%);
    transition: transform .3s; border-bottom: 1px solid rgba(255,107,53,.1);
  }
  .main-nav.open { transform: translateY(0); }
  .main-nav a { padding: 12px 16px; width: 100%; }
  .nav-toggle { display: flex; }
  .hero-content h1 { font-size: 1.8rem; }
  .hero-section { min-height: 400px; }
  .video-grid { grid-template-columns: 1fr; }
  .service-grid { grid-template-columns: 1fr; }
  .community-grid { grid-template-columns: repeat(2, 1fr); }
  .expert-grid { grid-template-columns: 1fr; }
  .review-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .stats-bar { flex-wrap: wrap; gap: 20px; }
  .section { padding: 50px 0; }
  .section-header h2 { font-size: 1.6rem; }
  .qrcode-area { flex-direction: column; align-items: center; }
}

@media (max-width: 480px) {
  .community-grid { grid-template-columns: 1fr; }
  .hero-content h1 { font-size: 1.5rem; }
  .search-wrap { flex-direction: column; border-radius: 14px; }
  .search-wrap input { border-radius: 0; }
  .search-wrap button { border-radius: 0; }
}

/* === 动画 === */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}
.animate-in { animation: fadeInUp .6s ease forwards; }

/* === 懒加载占位 === */
.lazy-placeholder {
  background: linear-gradient(90deg, #16213E 25%, #1a2744 50%, #16213E 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}
@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* === 时效性标记条 === */
.freshness-bar {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 24px; margin: 20px 0 0;
  background: rgba(255, 107, 53, .06);
  border: 1px solid rgba(255, 107, 53, .12);
  border-radius: 10px; font-size: .88rem; color: #999;
}
.fresh-badge {
  display: inline-block; padding: 4px 14px; border-radius: 14px;
  background: linear-gradient(135deg, #FF6B35, #E94560);
  color: #fff; font-size: .78rem; font-weight: 700; flex-shrink: 0;
}

/* === 视频时长标签 === */
.video-duration {
  position: absolute; bottom: 8px; right: 8px;
  padding: 2px 8px; border-radius: 4px;
  background: rgba(0,0,0,.75); color: #fff;
  font-size: .75rem; font-weight: 600; z-index: 2;
}

/* === 视频描述文字 === */
.video-desc {
  font-size: .82rem; color: #999; margin-bottom: 8px; line-height: 1.5;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}

/* === 视频多标签 === */
.video-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }

/* === 专家4列 === */
@media (min-width: 1025px) {
  .expert-grid { grid-template-columns: repeat(4, 1fr); }
}

/* === 首页面包屑位置调整 === */
.breadcrumb { margin-top: 68px; }
.search-bar { margin-top: 0; }

/* === 触摸激活态 === */
.video-card.touch-active .play-btn { opacity: 1; transform: translate(-50%, -50%) scale(1.05); }
.video-card.touch-active .video-thumb img { transform: scale(1.08); }