* {
  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: #f5f5f5;
}

.site-nav {
  background: #fff;
  border-bottom: 1px solid #e0e0e0;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.site-nav .logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: #333;
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  flex-wrap: nowrap;
  white-space: nowrap;
  overflow-x: visible;
}

.nav-links a {
  color: #666;
  text-decoration: none;
  transition: color 0.3s;
  font-size: 0.95rem;
}

.nav-links a:hover,
.nav-links a.active {
  color: #1a73e8;
}

main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2rem;
}

.hero-section {
  background: #fff;
  padding: 3rem 2rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  text-align: center;
}

.hero-title {
  font-size: 2rem;
  color: #333;
  margin-bottom: 1rem;
  line-height: 1.4;
}

.hero-desc {
  font-size: 1rem;
  color: #666;
  line-height: 1.8;
}

.intro-section {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  line-height: 1.8;
  color: #555;
}

.module {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  margin-bottom: 2rem;
}

.module-title {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  color: #333;
  border-left: 4px solid #1a73e8;
  padding-left: 1rem;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.video-card {
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  transition: transform 0.3s, box-shadow 0.3s;
  border: 1px solid #e0e0e0;
}

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

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

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

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

.video-info {
  padding: 1rem;
}

.video-title {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  color: #333;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.video-one-line {
  font-size: 0.9rem;
  color: #666;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.page-list {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
}

.page-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid #1a73e8;
}

.page-header h1 {
  font-size: 2rem;
  color: #333;
  margin-bottom: 0.5rem;
}

.page-desc {
  color: #666;
  line-height: 1.6;
}

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

.top-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  margin-bottom: 1rem;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  background: #fafafa;
  transition: background 0.3s;
}

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

.top-rank {
  font-size: 1.5rem;
  font-weight: bold;
  color: #1a73e8;
  min-width: 40px;
  text-align: center;
}

.top-item .video-cover {
  width: 120px;
  padding-top: 67.5px;
  flex-shrink: 0;
}

.top-item .video-info {
  flex: 1;
}

.top-item .video-title {
  font-size: 1.2rem;
}

.video-meta {
  font-size: 0.85rem;
  color: #999;
  margin-bottom: 0.5rem;
}

.page-detail {
  max-width: 1000px;
  margin: 0 auto;
}

.video-player-section {
  margin-bottom: 2rem;
}

.video-player {
  background: #000;
  border-radius: 8px;
  overflow: hidden;
}

.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(255,255,255,0.2);
  border: 3px solid #fff;
  border-radius: 50%;
  cursor: pointer;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.player-play-btn:hover {
  background: rgba(255,255,255,0.3);
  transform: translate(-50%, -50%) scale(1.1);
}

.player-play-icon {
  font-size: 2rem;
  color: #fff;
  margin-left: 4px;
}

.detail-header h1 {
  font-size: 2rem;
  color: #333;
  margin-bottom: 1rem;
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
}

.detail-info {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 1.5rem;
}

.detail-info h2 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: #333;
}

.info-list {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.5rem 1rem;
  line-height: 1.8;
}

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

.info-list dd {
  color: #666;
}

.detail-module {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 1.5rem;
}

.detail-module h2 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: #333;
  border-left: 4px solid #1a73e8;
  padding-left: 1rem;
}

.detail-module p {
  color: #555;
  line-height: 1.8;
  margin-bottom: 0.5rem;
}

.tag-cloud {
  margin-bottom: 1rem;
}

.tag {
  display: inline-block;
  padding: 0.3rem 0.8rem;
  background: #e3f2fd;
  color: #1a73e8;
  border-radius: 4px;
  margin-right: 0.5rem;
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
}

.video-card--related {
  border: 1px solid #e0e0e0;
}

.site-footer {
  background: #333;
  color: #fff;
  text-align: center;
  padding: 2rem;
  margin-top: 3rem;
}

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  background: #1a73e8;
  color: #fff;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
  transition: all 0.3s;
}

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

.back-to-top:hover {
  background: #1557b0;
  transform: translateY(-4px);
}

@media (max-width: 768px) {
  .site-nav {
    padding: 0.8rem 1rem;
    flex-wrap: wrap;
  }

  .nav-links {
    gap: 0.8rem;
    font-size: 0.85rem;
  }

  main {
    padding: 1rem;
  }

  .hero-title {
    font-size: 1.5rem;
  }

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

  .video-cover {
    padding-top: 50%;
  }

  .video-title {
    font-size: 0.95rem;
  }

  .video-one-line {
    font-size: 0.85rem;
  }

  .top-item {
    flex-direction: column;
    align-items: flex-start;
  }

  .top-item .video-cover {
    width: 100%;
  }

  .related-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.ui-style-7 {
  --primary-color: #0fa958;
  --accent-color: #00d66c;
}

.ui-style-7 .site-nav {
  background: #000;
}

.ui-style-7 .site-nav .logo {
  color: var(--accent-color);
}

.ui-style-7 .nav-links a {
  color: #aaa;
}

.ui-style-7 .nav-links a:hover,
.ui-style-7 .nav-links a.active {
  color: var(--accent-color);
}

.ui-style-7 .module-title {
  border-left-color: var(--primary-color);
}

.ui-style-7 .detail-module h2 {
  border-left-color: var(--primary-color);
}

.ui-style-7 .page-header {
  border-bottom-color: var(--primary-color);
}

.ui-style-7 .tag {
  background: rgba(15, 169, 88, 0.1);
  color: var(--primary-color);
}

.ui-style-7 .back-to-top {
  background: var(--primary-color);
}

.ui-style-7 .back-to-top:hover {
  background: var(--accent-color);
}