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

:root {
  --primary-red: #FF3B30;
  --bg-white: #FFFFFF;
  --text-dark: #1D1D1F;
  --text-gray: #86868B;
  --border-light: #E5E5EA;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.12);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-dark);
  background: var(--bg-white);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

body.ui-style-3 {
  --accent-color: var(--primary-red);
}

.main-nav {
  background: var(--bg-white);
  border-bottom: 1px solid var(--border-light);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow-sm);
}

.nav-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  font-size: 22px;
  font-weight: 600;
  color: var(--primary-red);
  letter-spacing: 0.5px;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 32px;
  align-items: center;
}

.nav-menu li a {
  text-decoration: none;
  color: var(--text-dark);
  font-size: 15px;
  font-weight: 500;
  transition: var(--transition);
  white-space: nowrap;
}

.nav-menu li a:hover {
  color: var(--primary-red);
}

main {
  flex: 1;
  width: 100%;
}

.skeleton-s3 {
  display: flex;
  flex-direction: column;
}

.hero-section {
  background: linear-gradient(135deg, #FFF 0%, #F9F9F9 100%);
  padding: 80px 24px 60px;
  text-align: center;
  border-bottom: 1px solid var(--border-light);
}

.hero-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--text-dark);
  margin-bottom: 16px;
  line-height: 1.3;
}

.hero-subtitle {
  font-size: 18px;
  color: var(--text-gray);
  font-weight: 400;
}

.content-with-sidebar {
  max-width: 1400px;
  margin: 0 auto;
  padding: 48px 24px;
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 48px;
}

.main-content {
  min-width: 0;
}

.sidebar {
  position: sticky;
  top: 88px;
  height: fit-content;
}

.intro-section {
  margin-bottom: 48px;
}

.intro-text {
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-gray);
  background: #F9F9F9;
  padding: 24px;
  border-radius: 12px;
  border-left: 4px solid var(--primary-red);
}

.video-section {
  margin-bottom: 56px;
}

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

.section-title {
  font-size: 24px;
  font-weight: 600;
  color: var(--text-dark);
  position: relative;
  padding-left: 16px;
}

.section-title::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 20px;
  background: var(--primary-red);
  border-radius: 2px;
}

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

.video-card {
  background: var(--bg-white);
  border-radius: 12px;
  overflow: hidden;
  transition: var(--transition);
  border: 1px solid var(--border-light);
  height: 100%;
}

.video-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.video-card__link {
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  height: 100%;
}

.video-cover {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  overflow: hidden;
  background: #F5F5F5;
}

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

.video-card:hover .video-cover img {
  transform: scale(1.05);
}

.video-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.video-card:hover .video-overlay {
  background: rgba(0, 0, 0, 0.3);
}

.play-icon {
  font-size: 48px;
  color: white;
  opacity: 0;
  transform: scale(0.8);
  transition: var(--transition);
}

.video-card:hover .play-icon {
  opacity: 1;
  transform: scale(1);
}

.video-info {
  padding: 16px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.video-title {
  font-size: 17px;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 8px;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  line-height: 1.4;
}

.video-one-line {
  font-size: 14px;
  color: var(--text-gray);
  margin-bottom: 12px;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  flex: 1;
}

.video-meta {
  display: flex;
  gap: 12px;
  font-size: 13px;
  color: var(--text-gray);
  flex-wrap: wrap;
}

.video-meta span {
  white-space: nowrap;
}

.sidebar-widget {
  background: #F9F9F9;
  border-radius: 12px;
  padding: 24px;
  margin-bottom: 24px;
}

.widget-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 16px;
}

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

.tag {
  display: inline-block;
  padding: 6px 14px;
  background: var(--bg-white);
  border: 1px solid var(--border-light);
  border-radius: 20px;
  font-size: 13px;
  color: var(--text-dark);
  text-decoration: none;
  transition: var(--transition);
}

.tag:hover {
  background: var(--primary-red);
  color: white;
  border-color: var(--primary-red);
}

.mini-list {
  list-style: none;
  padding-left: 0;
}

.mini-list li {
  margin-bottom: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-light);
}

.mini-list li:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.mini-list a {
  color: var(--text-dark);
  text-decoration: none;
  font-size: 14px;
  transition: var(--transition);
}

.mini-list a:hover {
  color: var(--primary-red);
}

.list-main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 48px 24px;
}

.page-header {
  margin-bottom: 40px;
}

.page-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--text-dark);
  margin-bottom: 12px;
}

.page-desc {
  font-size: 16px;
  color: var(--text-gray);
  line-height: 1.6;
}

.filter-bar {
  margin-bottom: 32px;
  padding: 16px;
  background: #F9F9F9;
  border-radius: 8px;
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.filter-label {
  font-weight: 500;
  color: var(--text-dark);
}

.filter-item {
  padding: 6px 16px;
  border-radius: 20px;
  background: var(--bg-white);
  color: var(--text-dark);
  text-decoration: none;
  font-size: 14px;
  border: 1px solid var(--border-light);
  transition: var(--transition);
}

.filter-item:hover,
.filter-item.active {
  background: var(--primary-red);
  color: white;
  border-color: var(--primary-red);
}

.layout-with-side {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 40px;
}

.layout__side--filters {
  position: sticky;
  top: 88px;
  height: fit-content;
}

.filter-widget {
  background: #F9F9F9;
  border-radius: 12px;
  padding: 20px;
}

.filter-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 16px;
}

.filter-list {
  list-style: none;
}

.filter-list li {
  margin-bottom: 12px;
}

.filter-list a {
  color: var(--text-dark);
  text-decoration: none;
  font-size: 14px;
  transition: var(--transition);
}

.filter-list a:hover {
  color: var(--primary-red);
}

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

.top-item {
  display: flex;
  gap: 20px;
  padding: 20px;
  background: var(--bg-white);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  transition: var(--transition);
  align-items: center;
}

.top-item:hover {
  box-shadow: var(--shadow-md);
}

.top-rank {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-gray);
  min-width: 60px;
  text-align: center;
}

.top-rank.rank-top {
  color: var(--primary-red);
  font-size: 36px;
}

.top-cover {
  width: 120px;
  height: 180px;
  flex-shrink: 0;
  border-radius: 8px;
  overflow: hidden;
  background: #F5F5F5;
}

.top-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.top-info {
  flex: 1;
  min-width: 0;
}

.top-title {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 12px;
}

.top-title a {
  color: var(--text-dark);
  text-decoration: none;
  transition: var(--transition);
}

.top-title a:hover {
  color: var(--primary-red);
}

.top-desc {
  font-size: 14px;
  color: var(--text-gray);
  margin-bottom: 12px;
  line-height: 1.6;
}

.top-meta {
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--text-gray);
}

.group {
  margin-bottom: 56px;
}

.group__title {
  font-size: 24px;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 24px;
  padding-left: 16px;
  border-left: 4px solid var(--primary-red);
}

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

.detail-main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px 48px;
}

.video-player-section {
  margin: 0 -24px 48px;
  background: #000;
}

.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;
  border-radius: 50%;
  background: rgba(255, 59, 48, 0.9);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

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

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

.detail-header {
  margin-bottom: 32px;
}

.detail-title {
  font-size: 36px;
  font-weight: 700;
  color: var(--text-dark);
  line-height: 1.3;
}

.detail-info {
  background: #F9F9F9;
  border-radius: 12px;
  padding: 32px;
  margin-bottom: 40px;
}

.info-title {
  font-size: 20px;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 20px;
}

.info-list {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px 24px;
  font-size: 15px;
  line-height: 1.8;
}

.info-list dt {
  font-weight: 500;
  color: var(--text-gray);
}

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

.detail-module {
  margin-bottom: 40px;
}

.module-title {
  font-size: 22px;
  font-weight: 600;
  color: var(--text-dark);
  margin-bottom: 20px;
  padding-left: 16px;
  border-left: 4px solid var(--primary-red);
}

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

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.tag-list .tag {
  padding: 8px 18px;
  font-size: 14px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 24px;
}

.video-card--related {
  background: #F9F9F9;
}

.site-footer {
  background: #F9F9F9;
  border-top: 1px solid var(--border-light);
  padding: 40px 24px;
  margin-top: auto;
}

.footer-container {
  max-width: 1400px;
  margin: 0 auto;
  text-align: center;
  color: var(--text-gray);
  font-size: 14px;
}

@media (max-width: 1024px) {
  .content-with-sidebar {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
  }

  .layout-with-side {
    grid-template-columns: 1fr;
  }

  .layout__side--filters {
    position: static;
  }
}

@media (max-width: 768px) {
  .nav-container {
    height: 56px;
  }

  .nav-menu {
    gap: 16px;
    font-size: 14px;
  }

  .hero-section {
    padding: 48px 16px 32px;
  }

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

  .hero-subtitle {
    font-size: 15px;
  }

  .content-with-sidebar,
  .list-main,
  .detail-main {
    padding: 32px 16px;
  }

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

  .page-title {
    font-size: 26px;
  }

  .section-title {
    font-size: 20px;
  }

  .top-item {
    flex-wrap: wrap;
  }

  .top-cover {
    width: 100px;
    height: 150px;
  }

  .detail-title {
    font-size: 26px;
  }

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

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

  .video-title {
    font-size: 15px;
    -webkit-line-clamp: 1;
  }

  .video-one-line {
    font-size: 13px;
    -webkit-line-clamp: 1;
  }
}

@media (max-width: 480px) {
  .nav-menu {
    gap: 8px;
    font-size: 13px;
  }

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