* {
  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;
}

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

.site-header {
  background: #1a1a1a;
  color: #fff;
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

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

.site-logo a {
  font-size: 1.5rem;
  font-weight: 700;
  color: #fff;
  text-decoration: none;
}

.main-nav {
  display: flex;
  gap: 1.5rem;
  flex-wrap: nowrap;
  white-space: nowrap;
}

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

.main-nav a:hover {
  color: #ffc107;
}

.hero-section {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  padding: 4rem 0;
  text-align: center;
}

.hero-title {
  font-size: 2rem;
  margin-bottom: 1rem;
  font-weight: 700;
}

.hero-subtitle {
  font-size: 1.2rem;
  opacity: 0.9;
}

.site-intro {
  background: #fff;
  padding: 3rem 0;
  margin: 2rem 0;
}

.site-intro h2 {
  font-size: 1.8rem;
  margin-bottom: 1.5rem;
  color: #1a1a1a;
}

.site-intro p {
  font-size: 1rem;
  line-height: 1.8;
  color: #555;
}

.content-section {
  margin: 2rem 0;
  padding: 2rem 0;
}

.section-header {
  margin-bottom: 2rem;
}

.section-header h2 {
  font-size: 1.8rem;
  color: #1a1a1a;
  border-left: 4px solid #667eea;
  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;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  transition: transform 0.3s, box-shadow 0.3s;
}

.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%;
  background: #e0e0e0;
  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;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: #1a1a1a;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.video-meta {
  font-size: 0.85rem;
  color: #666;
  margin-bottom: 0.5rem;
}

.video-desc {
  font-size: 0.9rem;
  color: #555;
  line-height: 1.5;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

.site-footer {
  background: #1a1a1a;
  color: #fff;
  text-align: center;
  padding: 2rem 0;
  margin-top: 3rem;
}

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  background: #667eea;
  color: #fff;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s;
  font-size: 1.5rem;
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: #5568d3;
}

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

.video-player {
  width: 100%;
  max-width: 1200px;
  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;
  font-size: 2rem;
  color: #667eea;
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.detail-page {
  background: #fff;
  padding: 2rem 0;
}

.detail-header {
  margin-bottom: 2rem;
}

.detail-header h1 {
  font-size: 2rem;
  color: #1a1a1a;
  margin-bottom: 1rem;
}

.detail-section {
  margin: 2rem 0;
  padding: 1.5rem;
  background: #f9f9f9;
  border-radius: 8px;
}

.detail-section h2 {
  font-size: 1.5rem;
  color: #1a1a1a;
  margin-bottom: 1rem;
  border-left: 4px solid #667eea;
  padding-left: 1rem;
}

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

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

.info-item {
  padding: 0.5rem 0;
}

.info-item strong {
  color: #1a1a1a;
  display: inline-block;
  min-width: 80px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1.5rem;
}

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

.page--grid {
  padding: 2rem 0;
}

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

.page-header h1 {
  font-size: 2rem;
  color: #1a1a1a;
  margin-bottom: 0.5rem;
}

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

.filter-bar {
  background: #fff;
  padding: 1.5rem;
  margin-bottom: 2rem;
  border-radius: 8px;
}

.pagination {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 2rem;
  padding: 1rem;
}

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

.page--top .top-list__item {
  background: #fff;
  padding: 1.5rem;
  margin-bottom: 1rem;
  border-radius: 8px;
  display: flex;
  gap: 1.5rem;
  align-items: center;
  counter-increment: top-counter;
}

.page--top .top-list__item::before {
  content: counter(top-counter);
  font-size: 2rem;
  font-weight: 700;
  color: #667eea;
  min-width: 50px;
  text-align: center;
}

.page--top .top-list__cover {
  width: 120px;
  height: 68px;
  flex-shrink: 0;
}

.page--top .top-list__cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 4px;
}

.page--top .top-list__info {
  flex: 1;
}

.page--top .top-list__title {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: #1a1a1a;
}

.page--top .top-list__meta {
  font-size: 0.9rem;
  color: #666;
  margin-bottom: 0.5rem;
}

.page--top .top-list__desc {
  font-size: 0.9rem;
  color: #555;
  line-height: 1.5;
}

body.ui-style-7 {
  font-family: "Helvetica Neue", Arial, sans-serif;
}

body.ui-style-7 .site-header {
  background: #1a2332;
}

body.ui-style-7 .hero-section {
  background: linear-gradient(135deg, #1a2332 0%, #364458 100%);
}

body.ui-style-7 .section-header h2 {
  border-left-color: #0099FF;
}

body.ui-style-7 .video-card:hover {
  box-shadow: 0 4px 20px rgba(0,153,255,0.2);
}

body.ui-style-7 .back-to-top {
  background: #0099FF;
}

body.ui-style-7 .back-to-top:hover {
  background: #0077CC;
}

body.ui-style-7 .player-play-btn {
  color: #0099FF;
}

body.ui-style-7 .detail-section h2 {
  border-left-color: #0099FF;
}

body.ui-style-7 .page--top .top-list__item::before {
  color: #0099FF;
}

@media (max-width: 768px) {
  .header-container {
    flex-direction: column;
    gap: 1rem;
  }

  .main-nav {
    gap: 0.8rem;
    font-size: 0.85rem;
    overflow-x: auto;
    width: 100%;
    justify-content: space-between;
  }

  .main-nav a {
    font-size: 0.85rem;
    white-space: nowrap;
    padding: 0 0.3rem;
  }

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

  .hero-subtitle {
    font-size: 1rem;
  }

  .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-desc {
    font-size: 0.85rem;
  }

  .detail-header h1 {
    font-size: 1.5rem;
  }

  .page--top .top-list__item {
    flex-direction: column;
    text-align: center;
  }

  .page--top .top-list__cover {
    width: 100%;
    height: auto;
    padding-top: 56.25%;
    position: relative;
  }

  .page--top .top-list__cover img {
    position: absolute;
    top: 0;
    left: 0;
  }
}