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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  color: #333;
  background: #fff;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.site-header {
  background: #fff;
  border-bottom: 1px solid #e5e5e5;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 16px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-logo a {
  font-size: 24px;
  font-weight: 700;
  color: #0099FF;
  text-decoration: none;
}

.site-nav {
  display: flex;
  gap: 24px;
  white-space: nowrap;
  overflow-x: auto;
  scrollbar-width: none;
}

.site-nav::-webkit-scrollbar {
  display: none;
}

.site-nav .nav-link {
  color: #333;
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  transition: color 0.2s;
  flex-shrink: 0;
}

.site-nav .nav-link:hover,
.site-nav .nav-link.active {
  color: #0099FF;
}

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

.hero-title {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 16px;
  line-height: 1.4;
}

.hero-subtitle {
  font-size: 16px;
  opacity: 0.95;
}

.intro-section {
  padding: 40px 20px;
  background: #f8f9fa;
}

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

.section-group {
  padding: 40px 0;
}

.group {
  margin-bottom: 48px;
}

.group__header {
  margin-bottom: 24px;
  border-bottom: 2px solid #0099FF;
  padding-bottom: 12px;
}

.group__title {
  font-size: 24px;
  font-weight: 700;
  color: #222;
}

.group__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.video-card {
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  transition: transform 0.2s, box-shadow 0.2s;
}

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}

.video-card__link {
  text-decoration: none;
  color: inherit;
  display: block;
}

.video-cover {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  overflow: hidden;
  background: #f0f0f0;
}

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

.video-info {
  padding: 16px;
}

.video-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
  color: #222;
  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;
}

.site-footer {
  background: #2c3e50;
  color: #fff;
  padding: 32px 20px;
  text-align: center;
  margin-top: 60px;
}

.footer-text {
  font-size: 14px;
  opacity: 0.9;
}

.back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  width: 48px;
  height: 48px;
  background: #0099FF;
  color: #fff;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 24px;
  display: none;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
  transition: background 0.2s;
  z-index: 99;
}

.back-to-top:hover {
  background: #0077cc;
}

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

.detail-page {
  padding-bottom: 40px;
}

.video-player-section {
  background: #000;
  margin-bottom: 32px;
}

.video-player {
  max-width: 1200px;
  margin: 0 auto;
}

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

.player-play-btn {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 80px;
  height: 80px;
  background: rgba(0, 153, 255, 0.9);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.player-play-btn:hover {
  background: #0099FF;
  transform: translate(-50%, -50%) scale(1.1);
}

.player-play-icon {
  font-size: 36px;
  color: #fff;
  margin-left: 4px;
}

.video-header {
  margin-bottom: 24px;
}

.video-main-title {
  font-size: 32px;
  font-weight: 700;
  color: #222;
  line-height: 1.3;
}

.video-basic-info {
  background: #f8f9fa;
  padding: 24px;
  border-radius: 8px;
  margin-bottom: 32px;
}

.info-list {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px 16px;
  font-size: 15px;
}

.info-list dt {
  font-weight: 600;
  color: #555;
}

.info-list dd {
  color: #333;
}

.content-module {
  margin-bottom: 32px;
}

.module-title {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 16px;
  color: #222;
  border-left: 4px solid #0099FF;
  padding-left: 12px;
}

.module-content {
  font-size: 15px;
  line-height: 1.8;
  color: #444;
}

.module-content p {
  margin-bottom: 12px;
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  display: inline-block;
  padding: 6px 12px;
  background: #e3f2fd;
  color: #0099FF;
  border-radius: 16px;
  font-size: 14px;
}

.related-section {
  margin-top: 48px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.video-card--related {
  box-shadow: 0 2px 6px rgba(0,0,0,0.08);
}

.list-page {
  padding: 32px 0;
}

.page-header {
  margin-bottom: 32px;
  padding-bottom: 16px;
  border-bottom: 2px solid #0099FF;
}

.page-header h1 {
  font-size: 32px;
  font-weight: 700;
  color: #222;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.page-layout {
  display: flex;
  gap: 32px;
}

.layout__side {
  width: 240px;
  flex-shrink: 0;
}

.layout__side h2 {
  font-size: 18px;
  margin-bottom: 16px;
  color: #222;
}

.layout__main {
  flex: 1;
  min-width: 0;
}

.top-list__items {
  list-style: none;
}

.top-list__item {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
  background: #fff;
  border-radius: 8px;
  padding: 16px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  align-items: center;
}

.rank-badge {
  font-size: 32px;
  font-weight: 700;
  color: #0099FF;
  min-width: 60px;
  text-align: center;
}

.top-item__link {
  display: flex;
  gap: 16px;
  flex: 1;
  text-decoration: none;
  color: inherit;
  align-items: center;
}

.top-list__item .video-cover {
  width: 160px;
  padding-top: 0;
  height: 90px;
  flex-shrink: 0;
}

.top-list__item .video-cover img {
  position: static;
}

.top-list__item .video-info {
  flex: 1;
  padding: 0;
}

.page--grouped .group {
  margin-bottom: 48px;
}

.page--grouped .group__title {
  font-size: 24px;
  margin-bottom: 20px;
  color: #222;
}

.ui-style-14 {
  --primary-color: #00A1D6;
  --accent-color: #FB7299;
}

.ui-style-14 .site-logo a {
  color: var(--primary-color);
}

.ui-style-14 .site-nav .nav-link:hover,
.ui-style-14 .site-nav .nav-link.active {
  color: var(--primary-color);
}

.ui-style-14 .hero-section {
  background: linear-gradient(135deg, #00A1D6 0%, #FB7299 100%);
}

.ui-style-14 .group__header {
  border-bottom-color: var(--primary-color);
}

.ui-style-14 .back-to-top {
  background: var(--primary-color);
}

.ui-style-14 .back-to-top:hover {
  background: #0088b8;
}

.ui-style-14 .player-play-btn {
  background: rgba(0, 161, 214, 0.9);
}

.ui-style-14 .player-play-btn:hover {
  background: var(--primary-color);
}

.ui-style-14 .module-title {
  border-left-color: var(--primary-color);
}

.ui-style-14 .tag {
  background: rgba(0, 161, 214, 0.1);
  color: var(--primary-color);
}

.ui-style-14 .rank-badge {
  color: var(--primary-color);
}

@media (max-width: 768px) {
  .header-container {
    flex-direction: row;
    padding: 12px 16px;
  }

  .site-logo a {
    font-size: 20px;
  }

  .site-nav {
    gap: 16px;
  }

  .site-nav .nav-link {
    font-size: 14px;
  }

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

  .hero-title {
    font-size: 22px;
  }

  .hero-subtitle {
    font-size: 14px;
  }

  .intro-section {
    padding: 24px 16px;
  }

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

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

  .video-info {
    padding: 12px;
  }

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

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

  .video-main-title {
    font-size: 24px;
  }

  .page-layout {
    flex-direction: column;
  }

  .layout__side {
    width: 100%;
  }

  .top-list__item {
    flex-direction: row;
    padding: 12px;
  }

  .rank-badge {
    font-size: 24px;
    min-width: 40px;
  }

  .top-item__link {
    flex-direction: row;
  }

  .top-list__item .video-cover {
    width: 100px;
    height: 56px;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    font-size: 20px;
  }

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

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

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

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

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