* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #f8f9fa;
  color: #212529;
  line-height: 1.6;
}

a {
  color: #3498db;
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover {
  color: #2980b9;
}

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

.page-header {
  padding: 40px 0 20px;
  border-bottom: 2px solid #e9ecef;
  margin-bottom: 30px;
}

.page-header h1 {
  margin: 0 0 10px;
  font-size: 28px;
  color: #2c3e50;
}

.site-intro {
  background: #fff;
  padding: 25px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  margin-bottom: 40px;
  line-height: 1.8;
}

.site-intro p {
  margin: 0;
  color: #555;
}

section {
  margin-bottom: 50px;
}

section h2 {
  font-size: 24px;
  color: #2c3e50;
  margin: 0 0 20px;
  padding-bottom: 10px;
  border-bottom: 3px solid #3498db;
}

.intro {
  color: #666;
  margin-bottom: 25px;
  font-size: 16px;
}

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

.video-card {
  background: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.08);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  position: relative;
}

.video-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.video-card h3 {
  margin: 0 0 10px;
  font-size: 18px;
}

.video-card h3 a {
  color: #2c3e50;
}

.video-card h3 a:hover {
  color: #3498db;
}

.video-card .meta {
  color: #999;
  font-size: 14px;
  margin: 8px 0;
}

.video-card .genre {
  color: #666;
  font-size: 14px;
  margin: 8px 0;
  font-weight: 500;
}

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

.video-card .date-badge {
  position: absolute;
  top: 15px;
  right: 15px;
  background: #3498db;
  color: #fff;
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: bold;
}

.video-list {
  background: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.08);
}

.list-item {
  padding: 15px;
  border-bottom: 1px solid #e9ecef;
  display: flex;
  align-items: center;
  gap: 15px;
}

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

.list-item .rank {
  font-weight: bold;
  color: #3498db;
  font-size: 18px;
  min-width: 30px;
}

.list-item a {
  flex: 1;
  color: #2c3e50;
  font-weight: 500;
}

.list-item a:hover {
  color: #3498db;
}

.list-item .year {
  color: #999;
  font-size: 14px;
}

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

.rank-item {
  background: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.08);
  display: flex;
  gap: 20px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.rank-item:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.rank-number {
  font-size: 32px;
  font-weight: bold;
  color: #3498db;
  min-width: 50px;
  text-align: center;
}

.rank-content {
  flex: 1;
}

.rank-content h3 {
  margin: 0 0 8px;
  font-size: 20px;
}

.rank-content h3 a {
  color: #2c3e50;
}

.rank-content h3 a:hover {
  color: #3498db;
}

.rank-content .meta {
  color: #999;
  font-size: 14px;
  margin: 5px 0;
}

.rank-content .one-line {
  color: #666;
  font-size: 14px;
  line-height: 1.6;
  margin-top: 8px;
}

.video-detail {
  background: #fff;
  padding: 30px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.video-detail h1 {
  margin: 0 0 20px;
  font-size: 32px;
  color: #2c3e50;
}

.video-detail h2 {
  font-size: 20px;
  color: #2c3e50;
  margin: 25px 0 15px;
  padding-bottom: 8px;
  border-bottom: 2px solid #e9ecef;
}

.video-info,
.video-highlight,
.video-summary,
.video-review,
.related-videos {
  margin-bottom: 30px;
}

.video-info p {
  margin: 10px 0;
  color: #555;
}

.video-info strong {
  color: #2c3e50;
  margin-right: 8px;
}

.video-one-line {
  color: #666;
  font-size: 14px;
  margin-top: 8px;
}

.topic-section {
  margin-bottom: 50px;
}

@media (max-width: 768px) {
  .container {
    padding: 15px;
  }

  .page-header {
    padding: 25px 0 15px;
  }

  .page-header h1 {
    font-size: 22px;
  }

  .video-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .video-detail {
    padding: 20px;
  }

  .video-detail h1 {
    font-size: 24px;
  }

  .rank-item {
    flex-direction: column;
    gap: 10px;
  }

  .rank-number {
    font-size: 24px;
    min-width: auto;
    text-align: left;
  }
}