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

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

.ui-style-14 {
  --primary-color: #1a5490;
  --secondary-color: #2d6ba8;
  --accent-color: #ff6b35;
  --text-color: #2c3e50;
  --bg-color: #ffffff;
  --bg-light: #f5f7fa;
  --border-color: #e1e8ed;
}

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

.site-header {
  background: var(--primary-color);
  color: #fff;
  padding: 15px 0;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-logo a {
  font-size: 24px;
  font-weight: 600;
  color: #fff;
  text-decoration: none;
}

.main-nav {
  display: flex;
  gap: 25px;
}

.main-nav a {
  color: #fff;
  text-decoration: none;
  font-size: 15px;
  padding: 8px 12px;
  border-radius: 4px;
  transition: background 0.3s;
  white-space: nowrap;
}

.main-nav a:hover,
.main-nav a.active {
  background: rgba(255, 255, 255, 0.15);
}

.home-page .intro-section {
  background: var(--bg-light);
  padding: 40px 0;
  border-bottom: 3px solid var(--primary-color);
}

.main-title {
  font-size: 28px;
  color: var(--primary-color);
  margin-bottom: 20px;
  font-weight: 600;
  line-height: 1.4;
}

.intro-content p {
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-color);
}

.video-section {
  padding: 50px 0;
}

.section-title {
  font-size: 24px;
  color: var(--primary-color);
  margin-bottom: 25px;
  font-weight: 600;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--accent-color);
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 25px;
}

.video-card {
  background: #fff;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  transition: transform 0.3s, box-shadow 0.3s;
}

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}

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

.video-cover {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  overflow: hidden;
  background: var(--bg-light);
}

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

.video-info {
  padding: 15px;
}

.video-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-color);
  margin-bottom: 8px;
  line-height: 1.4;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.video-meta {
  font-size: 13px;
  color: #7f8c8d;
  margin-bottom: 6px;
}

.video-one-line {
  font-size: 14px;
  color: #5a6c7d;
  line-height: 1.5;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.list-page {
  padding: 40px 0;
  min-height: 70vh;
}

.page-header {
  margin-bottom: 35px;
  padding-bottom: 20px;
  border-bottom: 3px solid var(--primary-color);
}

.page-header h1 {
  font-size: 32px;
  color: var(--primary-color);
  margin-bottom: 10px;
  font-weight: 600;
}

.page-desc {
  font-size: 16px;
  color: #5a6c7d;
  line-height: 1.6;
}

.page--l1 .video-grid {
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
}

.page--l2 {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 30px;
}

.layout__side--filters {
  background: var(--bg-light);
  padding: 20px;
  border-radius: 8px;
  height: fit-content;
  position: sticky;
  top: 80px;
}

.layout__side--filters h3 {
  color: var(--primary-color);
  margin-bottom: 10px;
}

.page--l3 .top-list__items {
  list-style: none;
}

.top-list__item {
  display: flex;
  gap: 15px;
  padding: 15px;
  background: #fff;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  margin-bottom: 15px;
  transition: box-shadow 0.3s;
}

.top-list__item:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.rank-badge {
  font-size: 24px;
  font-weight: 700;
  color: var(--accent-color);
  min-width: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.item-cover {
  width: 120px;
  flex-shrink: 0;
}

.item-cover img {
  width: 100%;
  height: auto;
  border-radius: 4px;
}

.item-info {
  flex: 1;
}

.item-title {
  font-size: 18px;
  margin-bottom: 6px;
}

.item-title a {
  color: var(--primary-color);
  text-decoration: none;
}

.item-title a:hover {
  text-decoration: underline;
}

.item-meta {
  font-size: 13px;
  color: #7f8c8d;
  margin-bottom: 6px;
}

.item-desc {
  font-size: 14px;
  color: #5a6c7d;
  line-height: 1.5;
}

.page--l4 .group {
  margin-bottom: 40px;
}

.group__title {
  font-size: 22px;
  color: var(--primary-color);
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--accent-color);
}

.group__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}

.detail-page {
  padding: 30px 0;
  min-height: 70vh;
}

.video-player-section {
  margin-bottom: 30px;
}

.video-player {
  max-width: 900px;
  margin: 0 auto;
}

.video-player-inner {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  background: #000;
  border-radius: 8px;
  overflow: hidden;
}

.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;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.player-play-icon {
  font-size: 32px;
  color: var(--primary-color);
  margin-left: 4px;
}

.title-section {
  margin-bottom: 25px;
}

.title-section h1 {
  font-size: 32px;
  color: var(--primary-color);
  font-weight: 600;
  line-height: 1.3;
}

.info-section,
.detail-module,
.related-section {
  margin-bottom: 30px;
  padding: 25px;
  background: #fff;
  border: 1px solid var(--border-color);
  border-radius: 8px;
}

.info-section h2,
.detail-module h2,
.related-section h2 {
  font-size: 20px;
  color: var(--primary-color);
  margin-bottom: 15px;
  font-weight: 600;
}

.info-list {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 12px 20px;
  font-size: 15px;
}

.info-list dt {
  color: #7f8c8d;
  font-weight: 600;
}

.info-list dd {
  color: var(--text-color);
}

.detail-module p {
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-color);
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.tag {
  background: var(--bg-light);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 14px;
  color: var(--primary-color);
  border: 1px solid var(--border-color);
}

.video-card--related {
  background: #fff;
}

.site-footer {
  background: var(--primary-color);
  color: #fff;
  padding: 30px 0;
  text-align: center;
  margin-top: 50px;
}

.site-footer p {
  font-size: 14px;
}

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: var(--accent-color);
  color: #fff;
  border: none;
  border-radius: 50%;
  font-size: 20px;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
  transition: all 0.3s;
  z-index: 99;
}

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

.back-to-top:hover {
  background: var(--primary-color);
  transform: translateY(-4px);
}

@media (max-width: 768px) {
  .site-header .container {
    flex-direction: column;
    gap: 15px;
  }

  .main-nav {
    width: 100%;
    justify-content: space-around;
    gap: 5px;
    flex-wrap: nowrap;
    overflow-x: auto;
  }

  .main-nav a {
    font-size: 14px;
    padding: 6px 10px;
    flex-shrink: 0;
  }

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

  .video-grid {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 15px;
  }

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

  .video-info {
    padding: 12px;
  }

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

  .page--l2 {
    grid-template-columns: 1fr;
  }

  .layout__side--filters {
    position: static;
  }

  .top-list__item {
    flex-direction: column;
  }

  .item-cover {
    width: 100%;
  }

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

  .title-section h1 {
    font-size: 24px;
  }

  .info-list {
    grid-template-columns: 70px 1fr;
    gap: 10px 15px;
    font-size: 14px;
  }

  .back-to-top {
    width: 45px;
    height: 45px;
    bottom: 20px;
    right: 20px;
  }
}

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

  .main-nav {
    gap: 0;
  }

  .main-nav a {
    font-size: 13px;
    padding: 5px 8px;
  }
}