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

.main-content {
  min-height: calc(100vh - 200px);
}

.hero-section {
  background: #fff;
  padding: 40px;
  border-radius: 8px;
  margin-bottom: 30px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.hero-section h1 {
  font-size: 2rem;
  color: #1a73e8;
  margin-bottom: 20px;
}

.intro-text {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #555;
}

.video-section {
  margin-bottom: 40px;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.section-header h2 {
  font-size: 1.5rem;
  color: #333;
}

.more-link {
  color: #1a73e8;
  font-size: 0.95rem;
}

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

.video-card {
  background: #fff;
  border-radius: 8px;
  padding: 20px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  transition: transform 0.3s, box-shadow 0.3s;
}

.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: 10px;
}

.video-meta {
  font-size: 0.85rem;
  color: #888;
  margin-bottom: 8px;
}

.video-desc {
  font-size: 0.95rem;
  color: #666;
  line-height: 1.6;
}

.topic-list {
  background: #fff;
  border-radius: 8px;
  padding: 20px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

.topic-item {
  display: flex;
  align-items: flex-start;
  padding: 15px 0;
  border-bottom: 1px solid #eee;
}

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

.rank-num {
  display: inline-block;
  width: 32px;
  height: 32px;
  line-height: 32px;
  text-align: center;
  background: #1a73e8;
  color: #fff;
  border-radius: 50%;
  font-weight: bold;
  margin-right: 15px;
  flex-shrink: 0;
}

.topic-content {
  flex: 1;
}

.topic-content h3 {
  font-size: 1.05rem;
  margin-bottom: 5px;
}

.topic-desc {
  font-size: 0.9rem;
  color: #666;
}

.video-list {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.list-item {
  background: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

.list-item h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.item-meta {
  font-size: 0.85rem;
  color: #888;
  margin-bottom: 8px;
}

.item-desc {
  font-size: 0.95rem;
  color: #666;
  line-height: 1.6;
}

.nav-links-text {
  margin-top: 20px;
  padding: 15px;
  background: #f9f9f9;
  border-radius: 8px;
  text-align: center;
}

.nav-links-text a {
  margin: 0 8px;
}

.page-header {
  background: #fff;
  padding: 30px;
  border-radius: 8px;
  margin-bottom: 30px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.page-header h1 {
  font-size: 1.8rem;
  color: #1a73e8;
  margin-bottom: 15px;
}

.page-desc {
  font-size: 1rem;
  color: #666;
  line-height: 1.8;
}

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

.list-item-large {
  background: #fff;
  padding: 25px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  position: relative;
}

.rank-badge {
  position: absolute;
  top: 20px;
  left: 20px;
  width: 40px;
  height: 40px;
  line-height: 40px;
  text-align: center;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  border-radius: 50%;
  font-weight: bold;
  font-size: 1.1rem;
}

.date-badge {
  position: absolute;
  top: 20px;
  right: 20px;
  padding: 5px 12px;
  background: #1a73e8;
  color: #fff;
  border-radius: 4px;
  font-size: 0.85rem;
}

.item-content {
  padding-left: 0;
}

.list-item-large .rank-badge + .item-content {
  padding-left: 60px;
}

.item-content h3 {
  font-size: 1.3rem;
  margin-bottom: 10px;
}

.item-highlight {
  font-size: 1rem;
  color: #1a73e8;
  margin-bottom: 10px;
  font-weight: 500;
}

.item-review {
  font-size: 0.95rem;
  color: #555;
  font-style: italic;
  margin-top: 10px;
  padding-left: 15px;
  border-left: 3px solid #1a73e8;
}

.detail-page {
  background: #fff;
  padding: 40px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.detail-header h1 {
  font-size: 2rem;
  color: #1a73e8;
  margin-bottom: 30px;
}

.detail-page section {
  margin-bottom: 35px;
}

.detail-page h2 {
  font-size: 1.3rem;
  color: #333;
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 2px solid #1a73e8;
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 15px;
}

.info-item {
  padding: 10px;
  background: #f9f9f9;
  border-radius: 4px;
  font-size: 0.95rem;
}

.info-item strong {
  color: #555;
}

.highlight-text {
  font-size: 1.2rem;
  color: #1a73e8;
  font-weight: 500;
  line-height: 1.8;
}

.detail-summary p,
.detail-review p {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #555;
}

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

.related-item {
  padding: 20px;
  background: #f9f9f9;
  border-radius: 8px;
  transition: background 0.3s;
}

.related-item:hover {
  background: #f0f0f0;
}

.related-item h3 {
  font-size: 1.05rem;
  margin-bottom: 8px;
}

.related-meta {
  font-size: 0.85rem;
  color: #888;
  margin-bottom: 8px;
}

.related-desc {
  font-size: 0.95rem;
  color: #666;
  line-height: 1.6;
}

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

.footer p {
  font-size: 0.9rem;
}

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

  .hero-section {
    padding: 25px 20px;
  }

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

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

  .detail-page {
    padding: 25px 20px;
  }

  .detail-header h1 {
    font-size: 1.5rem;
  }

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

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

  .rank-badge {
    width: 32px;
    height: 32px;
    line-height: 32px;
    font-size: 0.95rem;
  }

  .list-item-large .rank-badge + .item-content {
    padding-left: 50px;
  }
}