.site-header {
  max-width: 1200px;
  margin: 40px auto 20px;
  padding: 0 20px;
  text-align: center;
}

.site-header h1 {
  font-size: 32px;
  margin-bottom: 15px;
  color: #1a1a1a;
}

.site-desc {
  font-size: 16px;
  color: #666;
  line-height: 1.8;
  max-width: 900px;
  margin: 0 auto;
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
  min-height: calc(100vh - 200px);
}

section {
  background: #fff;
  border-radius: 8px;
  padding: 30px;
  margin-bottom: 30px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

section h2 {
  font-size: 24px;
  margin-bottom: 20px;
  color: #1a1a1a;
  border-left: 4px solid #1a73e8;
  padding-left: 15px;
}

.intro-section p {
  font-size: 15px;
  line-height: 1.8;
  color: #555;
}

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

.video-card {
  padding: 20px;
  border: 1px solid #e0e0e0;
  border-radius: 6px;
  transition: all 0.3s;
}

.video-card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  transform: translateY(-2px);
}

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

.video-card .meta {
  font-size: 13px;
  color: #888;
  margin-bottom: 10px;
}

.video-card .oneline {
  font-size: 14px;
  color: #555;
  line-height: 1.6;
}

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

.video-list li {
  padding: 12px 0;
  border-bottom: 1px solid #f0f0f0;
  font-size: 15px;
}

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

.year {
  color: #999;
  font-size: 13px;
}

.more-link {
  margin-top: 20px;
  text-align: right;
  font-size: 15px;
}

.page-header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  padding: 40px 20px;
  text-align: center;
  border-radius: 8px;
  margin-bottom: 30px;
}

.page-header h1 {
  font-size: 28px;
  margin-bottom: 10px;
}

.page-header p {
  font-size: 15px;
  opacity: 0.95;
}

.card-item {
  padding: 25px;
  border-bottom: 1px solid #e0e0e0;
  margin-bottom: 20px;
}

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

.card-item h2 {
  font-size: 20px;
  margin-bottom: 10px;
  border: none;
  padding: 0;
}

.card-item .meta {
  font-size: 13px;
  color: #888;
  margin-bottom: 12px;
}

.card-item .summary {
  font-size: 14px;
  line-height: 1.7;
  color: #555;
  margin-bottom: 12px;
}

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

.tag {
  display: inline-block;
  background: #f0f0f0;
  padding: 4px 12px;
  border-radius: 12px;
  font-size: 12px;
  color: #666;
}

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

.rank-item {
  display: flex;
  align-items: flex-start;
  padding: 20px;
  border-bottom: 1px solid #f0f0f0;
  transition: background 0.3s;
}

.rank-item:hover {
  background: #f9f9f9;
}

.rank-num {
  display: inline-block;
  width: 40px;
  height: 40px;
  line-height: 40px;
  text-align: center;
  background: #1a73e8;
  color: #fff;
  border-radius: 50%;
  font-weight: bold;
  font-size: 16px;
  flex-shrink: 0;
  margin-right: 20px;
}

.rank-content {
  flex: 1;
}

.rank-content h2 {
  font-size: 18px;
  margin-bottom: 8px;
  border: none;
  padding: 0;
}

.topic-group {
  margin-bottom: 35px;
}

.topic-group h2 {
  font-size: 20px;
  margin-bottom: 15px;
  color: #333;
}

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

.topic-list li {
  padding: 10px 0;
  border-bottom: 1px solid #f5f5f5;
  font-size: 14px;
  line-height: 1.6;
}

.latest-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.latest-card {
  padding: 20px;
  border: 1px solid #e0e0e0;
  border-radius: 6px;
  position: relative;
  transition: all 0.3s;
}

.latest-card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.date-tag {
  position: absolute;
  top: 10px;
  right: 10px;
  background: #1a73e8;
  color: #fff;
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 12px;
}

.latest-card h2 {
  font-size: 18px;
  margin-bottom: 10px;
  margin-top: 10px;
  border: none;
  padding: 0;
}

.latest-card .desc {
  font-size: 14px;
  color: #555;
  line-height: 1.6;
  margin-top: 10px;
}

.detail-page {
  background: #fff;
  border-radius: 8px;
  padding: 30px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.detail-header h1 {
  font-size: 28px;
  margin-bottom: 20px;
  color: #1a1a1a;
}

.detail-info dl {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 15px 20px;
  font-size: 15px;
}

.detail-info dt {
  font-weight: bold;
  color: #333;
}

.detail-info dd {
  color: #555;
}

.detail-oneline {
  background: #f9f9f9;
  padding: 25px;
  border-radius: 6px;
}

.highlight {
  font-size: 16px;
  line-height: 1.8;
  color: #333;
  font-weight: 500;
}

.detail-summary p, .detail-review p {
  font-size: 15px;
  line-height: 1.9;
  color: #555;
  text-align: justify;
}

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

.related-card {
  padding: 20px;
  border: 1px solid #e0e0e0;
  border-radius: 6px;
  transition: all 0.3s;
}

.related-card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.related-card h3 {
  font-size: 16px;
  margin-bottom: 8px;
}

footer {
  background: #333;
  color: #fff;
  text-align: center;
  padding: 30px 20px;
  margin-top: 50px;
}

footer p {
  font-size: 14px;
  opacity: 0.9;
}

@media (max-width: 768px) {
  .site-header h1 { font-size: 24px; }
  .video-grid, .latest-grid, .related-grid { grid-template-columns: 1fr; }
  section { padding: 20px; }
  .rank-num { width: 30px; height: 30px; line-height: 30px; font-size: 14px; margin-right: 15px; }
  .detail-info dl { grid-template-columns: 80px 1fr; gap: 10px 15px; }
}