body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1rem;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  padding: 1rem;
  text-align: center;
}

.hero {
  text-align: center;
  padding: 3rem 1rem;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  border-radius: 8px;
  margin-bottom: 2rem;
}

.hero h1 {
  font-size: 2rem;
  margin-bottom: 1rem;
}

.intro {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.intro h2 {
  margin-bottom: 1rem;
  color: #1f2937;
}

section {
  margin-bottom: 3rem;
}

section h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: #1f2937;
}

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

.video-card {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  transition: transform 0.2s, box-shadow 0.2s;
}

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

.video-card h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

.video-card .meta {
  font-size: 0.85rem;
  color: #666;
  margin-bottom: 0.5rem;
}

.video-card .oneline {
  font-size: 0.9rem;
  color: #555;
  line-height: 1.5;
}

.list-container {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.list-item {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.list-item h3 {
  margin-bottom: 0.5rem;
  font-size: 1.2rem;
}

.list-item .meta {
  font-size: 0.85rem;
  color: #666;
  margin-bottom: 0.75rem;
}

.list-item .summary {
  font-size: 0.95rem;
  color: #555;
  margin-bottom: 0.75rem;
  line-height: 1.6;
}

.list-item .tags {
  font-size: 0.85rem;
  color: #2563eb;
}

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

.rank-item {
  display: flex;
  align-items: flex-start;
  background: #fff;
  padding: 1rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.rank-num {
  font-size: 1.5rem;
  font-weight: bold;
  color: #2563eb;
  min-width: 3rem;
  text-align: center;
}

.rank-content {
  flex: 1;
}

.rank-content h3 {
  margin-bottom: 0.25rem;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.topic-card {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  position: relative;
}

.topic-tag {
  display: inline-block;
  background: #2563eb;
  color: #fff;
  padding: 0.25rem 0.75rem;
  border-radius: 4px;
  font-size: 0.8rem;
  margin-bottom: 0.75rem;
}

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

.latest-item {
  display: flex;
  background: #fff;
  padding: 1rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.latest-date {
  font-size: 1.2rem;
  font-weight: bold;
  color: #2563eb;
  min-width: 5rem;
  text-align: center;
  padding: 0.5rem;
}

.latest-content {
  flex: 1;
}

.latest-content h3 {
  margin-bottom: 0.25rem;
}

.detail-page {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.detail-page h1 {
  font-size: 2rem;
  margin-bottom: 1.5rem;
  color: #1f2937;
}

.detail-info {
  background: #f9fafb;
  padding: 1.5rem;
  border-radius: 6px;
  margin-bottom: 2rem;
}

.detail-info p {
  margin-bottom: 0.5rem;
}

.detail-oneline, .detail-summary, .detail-review {
  margin-bottom: 2rem;
}

.detail-oneline h2, .detail-summary h2, .detail-review h2 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: #1f2937;
}

.detail-summary p {
  line-height: 1.8;
  text-align: justify;
}

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

.related-card {
  background: #f9fafb;
  padding: 1rem;
  border-radius: 6px;
  border: 1px solid #e5e7eb;
}

.related-card h4 {
  margin-bottom: 0.5rem;
  font-size: 1rem;
}

.related-card .oneline {
  font-size: 0.85rem;
  color: #666;
}

.link-list {
  list-style: none;
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.link-list li {
  margin-bottom: 0.75rem;
  padding-left: 1rem;
  position: relative;
}

.link-list li:before {
  content: "→";
  position: absolute;
  left: 0;
  color: #2563eb;
}

.page-intro {
  background: #f0f9ff;
  padding: 1rem 1.5rem;
  border-left: 4px solid #2563eb;
  margin-bottom: 2rem;
  line-height: 1.7;
}

footer {
  background: #1f2937;
  color: #9ca3af;
  text-align: center;
  padding: 2rem 1rem;
  margin-top: 3rem;
}

@media (max-width: 768px) {
  .hero h1 { font-size: 1.5rem; }
  .video-grid { grid-template-columns: 1fr; }
  .topic-grid { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: 1fr; }
  main { padding: 1rem 0.5rem; }
  .detail-page { padding: 1rem; }
}