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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
  line-height: 1.8;
  color: #2c3e50;
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  min-height: 100vh;
}

a { color: #3498db; text-decoration: none; transition: color 0.3s; }
a:hover { color: #2980b9; text-decoration: underline; }

.header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.5rem 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.8rem;
  font-weight: bold;
  color: white;
  text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.nav {
  display: flex;
  flex-wrap: nowrap;
  gap: 0.5rem;
  align-items: center;
}

.nav a {
  color: white;
  padding: 0.6rem 1.2rem;
  border-radius: 6px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: background 0.3s;
}

.nav a:hover {
  background: rgba(255,255,255,0.2);
  text-decoration: none;
}

.main-content {
  max-width: 1200px;
  margin: 2rem auto;
  padding: 0 1rem;
}

.container {
  background: white;
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
  margin-bottom: 2rem;
}

.hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 3rem 2rem;
  border-radius: 12px;
  text-align: center;
  margin-bottom: 2rem;
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.hero h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  line-height: 1.4;
}

.intro-section p {
  font-size: 1.05rem;
  line-height: 2;
  color: #555;
}

.video-section {
  margin-bottom: 2rem;
}

.video-section.alt {
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  color: white;
  padding: 2rem;
  border-radius: 12px;
}

.video-section.alt a {
  color: white;
  text-decoration: underline;
}

.video-section h2 {
  font-size: 1.8rem;
  margin-bottom: 1.5rem;
  color: #2c3e50;
  border-left: 4px solid #667eea;
  padding-left: 1rem;
}

.video-section.alt h2 {
  color: white;
  border-left-color: white;
}

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

.video-card {
  background: white;
  padding: 1.5rem;
  border-radius: 8px;
  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(102, 126, 234, 0.2);
}

.video-card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
  color: #2c3e50;
}

.video-card .meta {
  color: #7f8c8d;
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.video-card .desc {
  color: #555;
  font-size: 0.95rem;
  line-height: 1.6;
}

.more-links {
  text-align: center;
  padding-top: 1rem;
  border-top: 1px solid #ecf0f1;
}

.more-links a {
  margin: 0 1rem;
  font-weight: 500;
}

.page-header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 3rem 2rem;
  border-radius: 12px;
  margin-bottom: 2rem;
}

.page-header h1 {
  font-size: 2.2rem;
  margin-bottom: 1rem;
}

.page-header .intro {
  font-size: 1.05rem;
  line-height: 1.8;
  opacity: 0.95;
}

.list-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.list-item {
  background: white;
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.06);
  display: flex;
  gap: 1rem;
  transition: box-shadow 0.3s;
}

.list-item:hover {
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.15);
}

.list-item .rank {
  font-size: 1.8rem;
  font-weight: bold;
  color: #667eea;
  min-width: 50px;
  text-align: center;
}

.list-item h3 {
  font-size: 1.3rem;
  margin-bottom: 0.5rem;
  color: #2c3e50;
}

.list-item .tags {
  color: #667eea;
  font-size: 0.9rem;
  margin: 0.3rem 0;
}

.detail-page .container {
  max-width: 900px;
  margin: 0 auto 2rem;
}

.detail-page h1 {
  font-size: 2rem;
  color: #2c3e50;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 3px solid #667eea;
}

.detail-page h2 {
  font-size: 1.5rem;
  color: #667eea;
  margin: 2rem 0 1rem;
}

.info-list {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.8rem 1rem;
  line-height: 1.8;
}

.info-list dt {
  font-weight: 600;
  color: #555;
}

.info-list dd {
  color: #666;
}

.highlight {
  font-size: 1.15rem;
  color: #667eea;
  font-weight: 500;
  line-height: 1.8;
  padding: 1rem;
  background: #f8f9ff;
  border-left: 4px solid #667eea;
  border-radius: 4px;
}

.summary-section p, .review-section p {
  font-size: 1.05rem;
  line-height: 2;
  color: #444;
  text-align: justify;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1.5rem;
}

.related-card {
  background: #f8f9fa;
  padding: 1.2rem;
  border-radius: 8px;
  transition: transform 0.3s;
}

.related-card:hover {
  transform: translateY(-4px);
  background: #e9ecef;
}

.related-card h4 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  color: #2c3e50;
}

.footer {
  background: #34495e;
  color: white;
  padding: 2rem 1rem;
  text-align: center;
  margin-top: 3rem;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
}

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

  .logo {
    font-size: 1.5rem;
  }

  .nav {
    width: 100%;
    justify-content: space-between;
    gap: 0.25rem;
  }

  .nav a {
    flex: 1 1 0;
    min-width: 0;
    padding: 0.5rem 0.3rem;
    font-size: 0.85rem;
    text-align: center;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

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

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

  .detail-page h1 {
    font-size: 1.6rem;
  }
}