* {
  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: #333;
  background: #f5f5f5;
}

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

header {
  background: #fff;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 20px;
  max-width: 1200px;
  margin: 0 auto;
}

.logo {
  font-size: 24px;
  font-weight: 700;
  color: #1a73e8;
  text-decoration: none;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 0;
  flex-wrap: nowrap;
  align-items: center;
}

nav a {
  text-decoration: none;
  color: #555;
  padding: 8px 15px;
  display: block;
  transition: all 0.3s;
  white-space: nowrap;
  font-size: 14px;
}

nav a:hover {
  color: #1a73e8;
  background: #f0f7ff;
  border-radius: 4px;
}

main {
  padding: 30px 0;
  min-height: calc(100vh - 200px);
}

.page-title {
  font-size: 32px;
  margin-bottom: 10px;
  color: #1a1a1a;
}

.page-desc {
  color: #666;
  font-size: 16px;
  margin-bottom: 30px;
  line-height: 1.8;
}

.section {
  background: #fff;
  padding: 30px;
  margin-bottom: 30px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.section-title {
  font-size: 24px;
  margin-bottom: 20px;
  color: #1a1a1a;
  border-left: 4px solid #1a73e8;
  padding-left: 15px;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 20px;
}

.video-card {
  background: #fafafa;
  border-radius: 8px;
  padding: 20px;
  transition: all 0.3s;
  border: 1px solid #e8e8e8;
}

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 16px rgba(0,0,0,0.1);
  border-color: #1a73e8;
}

.video-card h3 {
  font-size: 18px;
  margin-bottom: 10px;
  color: #1a1a1a;
}

.video-card h3 a {
  text-decoration: none;
  color: inherit;
}

.video-card h3 a:hover {
  color: #1a73e8;
}

.video-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 10px 0;
  font-size: 13px;
  color: #888;
}

.video-meta span {
  background: #f0f0f0;
  padding: 3px 10px;
  border-radius: 3px;
}

.video-desc {
  font-size: 14px;
  color: #666;
  line-height: 1.6;
  margin-top: 10px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

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

.video-list li {
  padding: 15px;
  border-bottom: 1px solid #f0f0f0;
  transition: background 0.3s;
}

.video-list li:hover {
  background: #f9f9f9;
}

.video-list li:last-child {
  border-bottom: none;
}

.video-list h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.video-list h3 a {
  text-decoration: none;
  color: #1a1a1a;
}

.video-list h3 a:hover {
  color: #1a73e8;
}

.detail-header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  padding: 40px;
  border-radius: 8px;
  margin-bottom: 30px;
}

.detail-header h1 {
  font-size: 36px;
  margin-bottom: 15px;
}

.detail-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  font-size: 15px;
}

.detail-content {
  background: #fff;
  padding: 40px;
  border-radius: 8px;
  margin-bottom: 30px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.detail-content h2 {
  font-size: 24px;
  margin: 30px 0 15px 0;
  color: #1a1a1a;
}

.detail-content p {
  line-height: 1.8;
  color: #555;
  margin-bottom: 15px;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 15px 0;
}

.tag {
  background: #e8f4ff;
  color: #1a73e8;
  padding: 5px 12px;
  border-radius: 20px;
  font-size: 13px;
}

footer {
  background: #2c3e50;
  color: #ecf0f1;
  text-align: center;
  padding: 30px 20px;
  margin-top: 50px;
}

footer p {
  margin: 5px 0;
}

@media (max-width: 768px) {
  nav ul {
    gap: 0;
    justify-content: space-between;
    width: 100%;
  }
  
  nav a {
    font-size: 12px;
    padding: 6px 8px;
    flex: 1 1 0;
    min-width: 0;
    text-align: center;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  
  .header-content {
    flex-direction: column;
    gap: 15px;
  }
  
  nav {
    width: 100%;
  }
  
  .video-grid {
    grid-template-columns: 1fr;
  }
  
  .page-title {
    font-size: 24px;
  }
  
  .detail-header h1 {
    font-size: 28px;
  }
  
  .section {
    padding: 20px;
  }
}

body.ui-style-7 {
  /* Layout variant: D */
}