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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "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(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.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: bold;
  color: #d32f2f;
  text-decoration: none;
}

nav {
  display: flex;
  flex-wrap: nowrap;
  gap: 10px;
  align-items: center;
}

nav a {
  text-decoration: none;
  color: #555;
  padding: 8px 16px;
  border-radius: 4px;
  transition: all 0.3s;
  white-space: nowrap;
  font-size: 15px;
}

nav a:hover {
  background: #f0f0f0;
  color: #d32f2f;
}

.hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 60px 20px;
  text-align: center;
  margin-bottom: 40px;
}

.hero h1 {
  font-size: 36px;
  margin-bottom: 20px;
  line-height: 1.3;
}

.intro-section {
  background: white;
  padding: 40px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  margin-bottom: 40px;
}

.intro-section p {
  font-size: 16px;
  line-height: 1.8;
  color: #555;
}

section {
  margin-bottom: 50px;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 25px;
  padding-bottom: 15px;
  border-bottom: 2px solid #e0e0e0;
}

.section-header h2 {
  font-size: 28px;
  color: #333;
}

.section-header a {
  color: #d32f2f;
  text-decoration: none;
  font-size: 14px;
}

.section-header a:hover {
  text-decoration: underline;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 25px;
}

.video-card {
  background: white;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  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-content {
  padding: 20px;
}

.video-card h3 {
  font-size: 18px;
  margin-bottom: 10px;
  color: #333;
}

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

.video-card h3 a:hover {
  color: #d32f2f;
}

.video-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 12px;
  font-size: 13px;
  color: #777;
}

.video-meta span {
  background: #f5f5f5;
  padding: 4px 10px;
  border-radius: 3px;
}

.video-desc {
  font-size: 14px;
  color: #666;
  line-height: 1.6;
  margin-top: 10px;
}

.list-page {
  background: white;
  padding: 40px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  margin-bottom: 30px;
}

.list-page h1 {
  font-size: 32px;
  margin-bottom: 20px;
  color: #333;
}

.list-intro {
  font-size: 16px;
  color: #555;
  line-height: 1.8;
  margin-bottom: 30px;
  padding-bottom: 20px;
  border-bottom: 2px solid #e0e0e0;
}

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

.video-list-item {
  background: #fafafa;
  padding: 20px;
  border-radius: 6px;
  border-left: 4px solid #d32f2f;
}

.video-list-item h3 {
  font-size: 20px;
  margin-bottom: 10px;
}

.video-list-item h3 a {
  text-decoration: none;
  color: #333;
}

.video-list-item h3 a:hover {
  color: #d32f2f;
}

.detail-page {
  background: white;
  padding: 40px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  margin-bottom: 30px;
}

.detail-page h1 {
  font-size: 36px;
  margin-bottom: 25px;
  color: #333;
}

.detail-meta {
  background: #f9f9f9;
  padding: 20px;
  border-radius: 6px;
  margin-bottom: 30px;
}

.detail-meta-row {
  display: flex;
  margin-bottom: 12px;
  font-size: 15px;
}

.detail-meta-label {
  font-weight: bold;
  width: 100px;
  color: #555;
}

.detail-meta-value {
  color: #777;
}

.detail-section {
  margin-bottom: 30px;
}

.detail-section h2 {
  font-size: 24px;
  margin-bottom: 15px;
  color: #333;
  border-left: 4px solid #d32f2f;
  padding-left: 15px;
}

.detail-section p {
  font-size: 16px;
  line-height: 1.8;
  color: #555;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.tag {
  background: #e3f2fd;
  color: #1976d2;
  padding: 5px 12px;
  border-radius: 15px;
  font-size: 13px;
}

.related-section {
  background: #f9f9f9;
  padding: 30px;
  border-radius: 8px;
  margin-top: 40px;
}

.related-section h2 {
  font-size: 24px;
  margin-bottom: 20px;
  color: #333;
}

footer {
  background: #333;
  color: #ccc;
  text-align: center;
  padding: 30px 20px;
  margin-top: 60px;
}

footer p {
  font-size: 14px;
}

@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    gap: 15px;
    padding: 12px 15px;
  }

  nav {
    width: 100%;
    justify-content: space-between;
    flex-wrap: nowrap;
    overflow: hidden;
  }

  nav a {
    flex: 1 1 0;
    min-width: 0;
    text-align: center;
    padding: 6px 8px;
    font-size: 13px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }

  .hero h1 {
    font-size: 24px;
  }

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

  .detail-page, .list-page, .intro-section {
    padding: 20px;
  }

  .detail-page h1 {
    font-size: 28px;
  }

  .section-header h2 {
    font-size: 22px;
  }
}

body.ui-style-13 {
  --primary-color: #d32f2f;
  --secondary-color: #1976d2;
}

body.ui-style-13 .hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

body.ui-style-13 nav a:hover {
  background: #ffe0e0;
}