:root {
  --primary-color: #2c3e50;
  --secondary-color: #3498db;
  --accent-color: #e74c3c;
  --bg-color: #f5f5f5;
  --card-bg: #ffffff;
  --text-color: #333;
  --text-light: #666;
  --border-color: #ddd;
  --hover-bg: #f0f0f0;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background: var(--bg-color);
}

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

header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 20px;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
}

.logo a {
  color: inherit;
  text-decoration: none;
}

header nav ul {
  list-style: none;
  display: flex;
  gap: 0;
  flex-wrap: nowrap;
  justify-content: space-between;
  align-items: center;
}

header nav ul li {
  flex: 1 1 0;
  min-width: 0;
  text-align: center;
}

header nav a {
  display: block;
  color: var(--text-color);
  text-decoration: none;
  padding: 0.5rem 1rem;
  transition: all 0.3s;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

header nav a:hover,
header nav a.active {
  color: var(--secondary-color);
  background: var(--hover-bg);
  border-radius: 4px;
}

main {
  min-height: calc(100vh - 200px);
  padding: 2rem 0;
}

h1 {
  font-size: 2rem;
  margin-bottom: 1.5rem;
  color: var(--primary-color);
  line-height: 1.3;
}

h2 {
  font-size: 1.5rem;
  margin: 2rem 0 1rem;
  color: var(--primary-color);
  border-left: 4px solid var(--secondary-color);
  padding-left: 1rem;
}

h3 {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
}

h3 a {
  color: var(--primary-color);
  text-decoration: none;
  transition: color 0.3s;
}

h3 a:hover {
  color: var(--secondary-color);
}

p {
  margin-bottom: 1rem;
  line-height: 1.8;
}

section {
  margin-bottom: 3rem;
}

.site-intro,
.page-intro,
.topic-intro {
  background: var(--card-bg);
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  border-left: 4px solid var(--secondary-color);
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

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

.video-card,
.entry-card {
  background: var(--card-bg);
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  transition: all 0.3s;
  border: 1px solid var(--border-color);
}

.video-card:hover,
.entry-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
}

.video-meta {
  color: var(--text-light);
  font-size: 0.9rem;
  margin: 0.5rem 0;
}

.video-desc {
  color: var(--text-color);
  line-height: 1.6;
}

.video-list,
.top-list,
.topic-list,
.latest-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.video-item,
.top-item,
.topic-item,
.latest-item {
  background: var(--card-bg);
  padding: 1.5rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  transition: all 0.3s;
}

.video-item:hover,
.top-item:hover,
.topic-item:hover,
.latest-item:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
  border-color: var(--secondary-color);
}

.top-item {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
}

.rank-number {
  flex-shrink: 0;
  width: 50px;
  height: 50px;
  background: var(--secondary-color);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 700;
  border-radius: 8px;
}

.top-content {
  flex: 1;
}

.recommend-text {
  color: var(--text-light);
  font-style: italic;
}

.latest-item {
  display: flex;
  gap: 1.5rem;
}

.update-date {
  flex-shrink: 0;
  color: var(--secondary-color);
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.25rem 0.75rem;
  background: rgba(52, 152, 219, 0.1);
  border-radius: 4px;
  align-self: flex-start;
}

.latest-content {
  flex: 1;
}

.entry-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.more-link {
  text-align: center;
  margin-top: 2rem;
}

.more-link a {
  color: var(--secondary-color);
  text-decoration: none;
  font-size: 1.1rem;
  transition: color 0.3s;
}

.more-link a:hover {
  color: var(--accent-color);
}

.detail-page .video-detail {
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.05);
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

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

.info-item .label {
  font-weight: 600;
  color: var(--text-light);
}

.info-item .value {
  color: var(--text-color);
}

.highlight-text {
  font-size: 1.1rem;
  color: var(--secondary-color);
  font-weight: 500;
  padding: 1rem;
  background: rgba(52, 152, 219, 0.05);
  border-radius: 4px;
  border-left: 4px solid var(--secondary-color);
}

.review-text {
  font-style: italic;
  color: var(--text-light);
  padding: 1rem;
  background: var(--hover-bg);
  border-radius: 4px;
  border-left: 4px solid var(--accent-color);
}

.decade-section {
  margin-bottom: 3rem;
}

.topic-desc {
  margin-top: 0.5rem;
}

.why-topic {
  margin-top: 0.5rem;
  color: var(--text-light);
  font-size: 0.95rem;
}

footer {
  background: var(--primary-color);
  color: white;
  padding: 2rem 0;
  margin-top: 4rem;
}

footer .container {
  text-align: center;
}

footer p {
  margin-bottom: 1rem;
}

footer nav {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

footer nav a {
  color: white;
  text-decoration: none;
  transition: opacity 0.3s;
}

footer nav a:hover {
  opacity: 0.8;
}

@media (max-width: 768px) {
  header .container {
    flex-direction: column;
    gap: 1rem;
    padding: 1rem 15px;
  }

  header nav {
    width: 100%;
  }

  header nav a {
    font-size: 0.85rem;
    padding: 0.5rem 0.3rem;
  }

  .logo {
    font-size: 1.3rem;
  }

  h1 {
    font-size: 1.5rem;
  }

  h2 {
    font-size: 1.3rem;
  }

  .video-grid {
    grid-template-columns: 1fr;
  }

  .entry-grid {
    grid-template-columns: 1fr;
  }

  .top-item {
    flex-direction: column;
    gap: 1rem;
  }

  .rank-number {
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
  }

  .latest-item {
    flex-direction: column;
    gap: 0.5rem;
  }

  .update-date {
    align-self: flex-start;
  }

  footer nav {
    flex-direction: column;
    gap: 0.5rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 15px;
  }

  header nav a {
    font-size: 0.75rem;
    padding: 0.4rem 0.2rem;
  }

  h1 {
    font-size: 1.3rem;
  }

  .info-grid {
    grid-template-columns: 1fr;
  }
}