:root {
  --primary-color: #007bff;
  --secondary-color: #434343;
  --accent-color: #ff6b6b;
  --text-color: #333;
  --text-muted: #666;
  --bg-color: #f5f5f5;
  --white: #fff;
  --border-color: #ddd;
  --shadow: 0 2px 8px rgba(0,0,0,0.1);
  --transition: all 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", "微软雅黑", sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background: var(--bg-color);
  font-display: swap;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: var(--transition);
}

a:hover, a:focus {
  color: var(--accent-color);
}

button {
  border: none;
  background: none;
  cursor: pointer;
  font-family: inherit;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 15px;
}

.header {
  background: var(--secondary-color);
  color: var(--white);
  padding: 10px 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow);
}

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

.logo {
  font-size: 0;
}

.logo a {
  color: var(--white);
  font-size: 24px;
  font-weight: bold;
  text-decoration: none;
}

.nav ul {
  display: flex;
  list-style: none;
  gap: 20px;
  margin: 0;
}

.nav a {
  color: var(--white);
  padding: 8px 12px;
  border-radius: 4px;
  transition: var(--transition);
  display: block;
}

.nav a:hover, .nav a:focus {
  background: rgba(255,255,255,0.1);
  color: var(--white);
}

.search {
  display: flex;
  gap: 5px;
  align-items: center;
}

.search-input {
  padding: 8px 12px;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  width: 200px;
  font-size: 14px;
}

.search-input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.search-btn {
  padding: 8px 16px;
  background: var(--accent-color);
  color: var(--white);
  border-radius: 4px;
  font-size: 14px;
  transition: var(--transition);
}

.search-btn:hover, .search-btn:focus {
  background: #e55555;
  transform: translateY(-1px);
}

.menu-toggle {
  display: none;
  color: var(--white);
  font-size: 20px;
  padding: 5px;
}

.main {
  padding: 20px 0;
  min-height: calc(100vh - 200px);
}

.breadcrumb {
  margin-bottom: 20px;
  font-size: 14px;
}

.breadcrumb ol {
  display: flex;
  list-style: none;
  gap: 5px;
  align-items: center;
  flex-wrap: wrap;
}

.breadcrumb li:not(:last-child)::after {
  content: ">";
  margin-left: 5px;
  color: var(--text-muted);
}

.content-wrapper {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 20px;
  align-items: start;
}

.video-info {
  display: flex;
  gap: 20px;
  background: var(--white);
  padding: 20px;
  border-radius: 8px;
  margin-bottom: 20px;
  box-shadow: var(--shadow);
  position: relative;
}

.video-thumb {
  flex-shrink: 0;
  position: relative;
  overflow: hidden;
  border-radius: 6px;
}

.thumb-img {
  width: 220px;
  height: 330px;
  object-fit: cover;
  transition: var(--transition);
}

.play-overlay {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: rgba(0,0,0,0.7);
  color: var(--white);
  width: 60px;
  height: 60px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  cursor: pointer;
  transition: var(--transition);
  opacity: 0.8;
}

.play-overlay:hover {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1.1);
}

.video-details h2 {
  font-size: 28px;
  margin-bottom: 15px;
  color: var(--text-color);
  line-height: 1.3;
}

.rating {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 15px;
}

.stars {
  display: flex;
  gap: 2px;
}

.star {
  width: 16px;
  height: 16px;
  background: var(--border-color);
  clip-path: polygon(50% 0%, 61% 35%, 98% 35%, 68% 57%, 79% 91%, 50% 70%, 21% 91%, 32% 57%, 2% 35%, 39% 35%);
  transition: var(--transition);
}

.star.active {
  background: #ffd700;
}

.score {
  font-weight: bold;
  color: var(--accent-color);
  font-size: 18px;
}

.meta {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 8px 15px;
  align-items: center;
}

.meta dt {
  color: var(--text-muted);
  font-weight: normal;
}

.meta dd {
  margin: 0;
}

.meta a {
  margin-right: 8px;
}

.highlight {
  color: var(--accent-color);
  font-weight: bold;
}

.description, .playlist, .recommendations {
  background: var(--white);
  padding: 20px;
  border-radius: 8px;
  margin-bottom: 20px;
  box-shadow: var(--shadow);
}

.description h3, .playlist h3, .recommendations h3 {
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--primary-color);
  font-size: 20px;
  position: relative;
}

.description h3::after, .playlist h3::after, .recommendations h3::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 30px;
  height: 2px;
  background: var(--accent-color);
}

.desc-content {
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-color);
}

.playlist-tabs, .rec-tabs {
  display: flex;
  gap: 10px;
  margin-bottom: 15px;
  flex-wrap: wrap;
}

.tab, .rec-tab {
  padding: 10px 16px;
  background: #f8f9fa;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  cursor: pointer;
  transition: var(--transition);
  font-size: 14px;
  font-weight: 500;
}

.tab:hover, .rec-tab:hover,
.tab:focus, .rec-tab:focus {
  border-color: var(--primary-color);
  transform: translateY(-1px);
}

.tab.active, .rec-tab.active {
  background: var(--primary-color);
  color: var(--white);
  border-color: var(--primary-color);
}

.tab-content, .rec-tab-content {
  display: none;
}

.tab-content.active, .rec-tab-content.active {
  display: block;
}

.episode-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 10px;
  list-style: none;
}

.episode-btn {
  display: block;
  padding: 10px 16px;
  background: #f8f9fa;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  text-decoration: none;
  color: var(--text-color);
  transition: var(--transition);
  text-align: center;
  font-size: 14px;
}

.episode-btn:hover, .episode-btn:focus {
  background: var(--primary-color);
  color: var(--white);
  border-color: var(--primary-color);
  transform: translateY(-2px);
}

.episode-btn.current {
  background: var(--accent-color);
  color: var(--white);
  border-color: var(--accent-color);
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 15px;
}

.video-card {
  background: var(--white);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  position: relative;
}

.video-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.video-card img {
  width: 100%;
  height: 240px;
  object-fit: cover;
  transition: var(--transition);
}

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

.video-card-info {
  padding: 12px;
}

.video-card h4 {
  margin-bottom: 5px;
  font-size: 14px;
  line-height: 1.4;
  color: var(--text-color);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.video-card p {
  font-size: 12px;
  color: var(--text-muted);
  margin: 0;
}

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.hot-list, .tags-cloud {
  background: var(--white);
  padding: 20px;
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.hot-list h3, .tags-cloud h3 {
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--primary-color);
  font-size: 18px;
  position: relative;
}

.hot-list h3::after, .tags-cloud h3::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 25px;
  height: 2px;
  background: var(--accent-color);
}

.hot-videos {
  list-style: none;
  counter-reset: ranking;
}

.hot-videos li {
  counter-increment: ranking;
  margin-bottom: 10px;
  padding: 8px;
  border-radius: 6px;
  transition: var(--transition);
  position: relative;
  padding-left: 35px;
}

.hot-videos li::before {
  content: counter(ranking);
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--primary-color);
  color: var(--white);
  width: 20px;
  height: 20px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: bold;
}

.hot-videos li:nth-child(1)::before { background: #ff6b6b; }
.hot-videos li:nth-child(2)::before { background: #ffa500; }
.hot-videos li:nth-child(3)::before { background: #32cd32; }

.hot-videos li:hover {
  background: #f8f9fa;
}

.hot-videos a {
  text-decoration: none;
  color: var(--text-color);
  font-size: 14px;
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

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

.tag {
  padding: 4px 8px;
  background: #f8f9fa;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  font-size: 12px;
  color: var(--text-color);
  text-decoration: none;
  transition: var(--transition);
}

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

.footer {
  background: var(--secondary-color);
  color: var(--white);
  padding: 30px 0;
  margin-top: 40px;
}

.footer-content {
  text-align: center;
}

.footer-links {
  margin-bottom: 15px;
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--white);
  font-size: 14px;
  opacity: 0.8;
  transition: var(--transition);
}

.footer-links a:hover, .footer-links a:focus {
  opacity: 1;
  color: var(--white);
}

.footer p {
  font-size: 14px;
  opacity: 0.8;
  margin-bottom: 5px;
  line-height: 1.5;
}

.footer a {
  color: var(--white);
  opacity: 0.8;
}

.footer a:hover, .footer a:focus {
  opacity: 1;
  color: var(--white);
}

.mobile-nav {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--white);
  border-top: 1px solid var(--border-color);
  padding: 8px 0;
  z-index: 1000;
  box-shadow: 0 -2px 10px rgba(0,0,0,0.1);
}

.mobile-nav {
  display: flex;
  justify-content: space-around;
}

.nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-decoration: none;
  color: var(--text-muted);
  padding: 5px;
  transition: var(--transition);
  border-radius: 6px;
}

.nav-item:hover, .nav-item:focus {
  color: var(--primary-color);
  background: rgba(0,123,255,0.1);
}

.nav-icon {
  font-size: 18px;
  margin-bottom: 2px;
}

.nav-text {
  font-size: 11px;
  font-weight: 500;
}

.back-to-top {
  position: fixed;
  bottom: 80px;
  right: 20px;
  width: 50px;
  height: 50px;
  background: var(--primary-color);
  color: var(--white);
  border-radius: 50%;
  font-size: 20px;
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition);
  z-index: 999;
  box-shadow: var(--shadow);
}

.back-to-top:hover, .back-to-top:focus {
  background: var(--accent-color);
  transform: translateY(-3px);
}

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

@media (max-width: 1024px) {
  .content-wrapper {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    order: -1;
  }
  
  .video-grid {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  }
}

@media (max-width: 768px) {
  :root {
    font-size: 14px;
  }
  
  .header .container {
    flex-wrap: wrap;
    gap: 10px;
  }
  
  .nav {
    display: none;
    width: 100%;
    order: 3;
  }
  
  .nav.show {
    display: block;
  }
  
  .nav ul {
    flex-direction: column;
    gap: 0;
    background: rgba(255,255,255,0.1);
    border-radius: 6px;
    padding: 10px 0;
    margin-top: 10px;
  }
  
  .nav a {
    padding: 12px 20px;
    border-radius: 0;
  }
  
  .menu-toggle {
    display: block;
  }
  
  .search {
    order: 2;
  }
  
  .search-input {
    width: 180px;
  }
  
  .video-info {
    flex-direction: column;
    text-align: center;
  }
  
  .thumb-img {
    width: 100%;
    max-width: 280px;
    height: auto;
    margin: 0 auto;
  }
  
  .video-details h2 {
    font-size: 24px;
  }
  
  .meta {
    grid-template-columns: 1fr;
    gap: 8px;
    text-align: left;
  }
  
  .meta dt {
    font-weight: bold;
    margin-top: 8px;
  }
  
  .meta dt:first-child {
    margin-top: 0;
  }
  
  .video-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }
  
  .episode-list {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    gap: 8px;
  }
  
  .mobile-nav {
    display: flex;
  }
  
  body {
    padding-bottom: 70px;
  }
  
  .back-to-top {
    bottom: 90px;
    right: 15px;
    width: 45px;
    height: 45px;
    font-size: 18px;
  }
  
  .playlist-tabs, .rec-tabs {
    justify-content: center;
  }
  
  .footer-links {
    flex-direction: column;
    gap: 10px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 10px;
  }
  
  .video-info, .description, .playlist, .recommendations, .hot-list, .tags-cloud {
    padding: 15px;
  }
  
  .video-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }
  
  .video-card img {
    height: 200px;
  }
  
  .search-input {
    width: 150px;
  }
  
  .logo a {
    font-size: 20px;
  }
  
  .breadcrumb {
    font-size: 13px;
  }
  
  .episode-list {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .episode-btn {
    padding: 8px 12px;
    font-size: 13px;
  }
}

@media (max-width: 360px) {
  .search {
    width: 100%;
    margin-top: 10px;
  }
  
  .search-input {
    flex: 1;
    min-width: 0;
  }
  
  .header .container {
    flex-direction: column;
    align-items: stretch;
  }
  
  .logo {
    text-align: center;
    margin-bottom: 10px;
  }
  
  .menu-toggle {
    position: absolute;
    top: 15px;
    right: 15px;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  html {
    scroll-behavior: auto;
  }
}

@media print {
  .header, .mobile-nav, .back-to-top, .sidebar {
    display: none;
  }
  
  .main {
    padding: 0;
  }
  
  .video-info {
    box-shadow: none;
    border: 1px solid #ccc;
  }
}