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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  line-height: 1.6;
  color: #333;
  background: #f5f5f5;
}

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

a {
  text-decoration: none;
  color: inherit;
}

.site-nav {
  background: #fff;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav__container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 40px;
  height: 60px;
}

.site-logo {
  font-size: 24px;
  font-weight: 700;
  color: #00A1D6;
  white-space: nowrap;
}

.nav__links {
  display: flex;
  gap: 24px;
  flex-wrap: nowrap;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.nav__links::-webkit-scrollbar {
  display: none;
}

.nav__link {
  color: #333;
  font-size: 15px;
  white-space: nowrap;
  padding: 8px 0;
  transition: color 0.3s;
}

.nav__link:hover {
  color: #00A1D6;
}

.main-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 20px;
}

.hero-section {
  text-align: center;
  padding: 60px 20px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  border-radius: 16px;
  margin-bottom: 40px;
}

.hero__title {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 16px;
  line-height: 1.4;
}

.hero__subtitle {
  font-size: 18px;
  opacity: 0.95;
  max-width: 800px;
  margin: 0 auto;
}

.site-intro {
  background: #fff;
  padding: 30px;
  border-radius: 12px;
  margin-bottom: 40px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.intro__text {
  font-size: 15px;
  line-height: 1.8;
  color: #555;
}

.video-section {
  margin-bottom: 50px;
}

.section__container {
  background: #fff;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.section__title {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 24px;
  color: #333;
  border-left: 4px solid #00A1D6;
  padding-left: 16px;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 24px;
}

.video-card {
  background: #fff;
  border-radius: 12px;
  overflow: hidden;
  transition: transform 0.3s, box-shadow 0.3s;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.15);
}

.video-card__link {
  display: block;
}

.video-cover {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  background: #e0e0e0;
  overflow: hidden;
}

.video-cover img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.video-cover--small {
  padding-top: 0;
  width: 120px;
  height: 180px;
  flex-shrink: 0;
}

.video-cover--small img {
  position: static;
}

.video-info {
  padding: 16px;
}

.video-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
  color: #333;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.video-one-line {
  font-size: 14px;
  color: #666;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.video-meta {
  font-size: 13px;
  color: #999;
  margin-bottom: 8px;
}

.page-header {
  margin-bottom: 30px;
}

.page-header h1 {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 12px;
  color: #333;
}

.page-desc {
  font-size: 15px;
  color: #666;
  line-height: 1.8;
}

.page--grid {
  background: #fff;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.page--with-sidebar {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 30px;
}

.layout__side--filters {
  background: #fff;
  padding: 24px;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
  height: fit-content;
  position: sticky;
  top: 80px;
}

.layout__side--filters h3 {
  font-size: 18px;
  margin-bottom: 12px;
  color: #333;
}

.layout__main {
  background: #fff;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.page--top {
  background: #fff;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.top-list__items {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.top-list__item {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  padding: 20px;
  background: #f9f9f9;
  border-radius: 12px;
  transition: background 0.3s;
}

.top-list__item:hover {
  background: #f0f0f0;
}

.top-rank {
  font-size: 28px;
  font-weight: 700;
  color: #00A1D6;
  min-width: 50px;
  text-align: center;
}

.page--grouped {
  background: #fff;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.group {
  margin-bottom: 50px;
}

.group:last-child {
  margin-bottom: 0;
}

.group__title {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 24px;
  color: #333;
  border-left: 4px solid #00A1D6;
  padding-left: 16px;
}

.group__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 24px;
}

.detail-page {
  max-width: 900px;
}

.video-player-section {
  margin-bottom: 40px;
}

.video-player {
  width: 100%;
  background: #000;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(0,0,0,0.2);
}

.video-player-inner {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  background: #000;
}

.player-play-btn {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 80px;
  height: 80px;
  background: rgba(255,255,255,0.9);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s;
}

.player-play-btn:hover {
  background: #fff;
  transform: translate(-50%, -50%) scale(1.1);
}

.player-play-icon {
  font-size: 32px;
  color: #333;
  margin-left: 4px;
}

.detail-header {
  margin-bottom: 30px;
}

.detail-title {
  font-size: 36px;
  font-weight: 700;
  color: #333;
  line-height: 1.3;
}

.detail-info {
  margin-bottom: 30px;
}

.info__title {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 16px;
  color: #333;
}

.info__list {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px 24px;
  background: #f9f9f9;
  padding: 24px;
  border-radius: 12px;
}

.info__list dt {
  font-weight: 600;
  color: #666;
}

.info__list dd {
  color: #333;
}

.detail-module {
  margin-bottom: 30px;
}

.module__title {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 16px;
  color: #333;
  border-left: 4px solid #00A1D6;
  padding-left: 16px;
}

.module__content {
  font-size: 15px;
  line-height: 1.8;
  color: #555;
}

.module__content p {
  margin-bottom: 12px;
}

.tags-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.tag {
  display: inline-block;
  padding: 6px 16px;
  background: #e8f4fd;
  color: #00A1D6;
  border-radius: 20px;
  font-size: 14px;
}

.related-section {
  margin-top: 50px;
}

.video-grid--related {
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
}

.site-footer {
  background: #333;
  color: #fff;
  padding: 40px 20px;
  text-align: center;
  margin-top: 60px;
}

.footer__text {
  font-size: 14px;
  opacity: 0.8;
}

.back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  width: 50px;
  height: 50px;
  background: #00A1D6;
  color: #fff;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
  transition: all 0.3s;
  z-index: 99;
}

.back-to-top:hover {
  background: #0088b8;
  transform: translateY(-4px);
}

.back-to-top.show {
  display: flex;
}

.ui-style-13 {
  background: #f0f2f5;
}

.ui-style-13 .hero-section {
  background: linear-gradient(135deg, #00A1D6 0%, #00C75A 100%);
}

.ui-style-13 .site-logo {
  color: #00A1D6;
}

.ui-style-13 .nav__link:hover {
  color: #00A1D6;
}

.ui-style-13 .section__title {
  border-left-color: #00A1D6;
}

.ui-style-13 .module__title {
  border-left-color: #00A1D6;
}

.ui-style-13 .tag {
  background: #e8f4fd;
  color: #00A1D6;
}

.ui-style-13 .top-rank {
  color: #00A1D6;
}

.ui-style-13 .back-to-top {
  background: #00A1D6;
}

.ui-style-13 .back-to-top:hover {
  background: #0088b8;
}

@media (max-width: 768px) {
  .nav__container {
    gap: 16px;
    height: auto;
    padding: 12px 16px;
  }

  .site-logo {
    font-size: 18px;
  }

  .nav__links {
    gap: 16px;
  }

  .nav__link {
    font-size: 14px;
    padding: 4px 0;
  }

  .hero-section {
    padding: 40px 16px;
  }

  .hero__title {
    font-size: 24px;
  }

  .hero__subtitle {
    font-size: 15px;
  }

  .main-content {
    padding: 20px 16px;
  }

  .section__container {
    padding: 20px;
  }

  .video-grid {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 16px;
  }

  .video-info {
    padding: 12px;
  }

  .video-title {
    font-size: 14px;
  }

  .video-one-line {
    font-size: 13px;
  }

  .page--with-sidebar {
    grid-template-columns: 1fr;
  }

  .layout__side--filters {
    position: static;
  }

  .page--grid,
  .layout__main,
  .page--top,
  .page--grouped {
    padding: 24px 16px;
  }

  .page-header h1 {
    font-size: 24px;
  }

  .top-list__item {
    flex-direction: column;
    gap: 12px;
  }

  .video-cover--small {
    width: 100%;
    height: auto;
    padding-top: 56.25%;
  }

  .video-cover--small img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
  }

  .detail-title {
    font-size: 24px;
  }

  .info__list {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .module__title {
    font-size: 18px;
  }

  .module__content {
    font-size: 14px;
  }

  .video-grid--related {
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 44px;
    height: 44px;
    font-size: 20px;
  }
}

@media (max-width: 480px) {
  .video-grid {
    grid-template-columns: 1fr;
  }

  .video-cover {
    padding-top: 45%;
  }

  .group__grid {
    grid-template-columns: 1fr;
  }
}