.container { max-width: 1200px; margin: 0 auto; padding: 2rem 1rem; }
h1, h2, h3 { margin: 1rem 0 0.5rem; color: #2c3e50; }
h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; border-bottom: 2px solid #3498db; padding-bottom: 0.5rem; }
h3 { font-size: 1.2rem; }
a { color: #3498db; text-decoration: none; }
a:hover { text-decoration: underline; }

.hero { text-align: center; padding: 3rem 1rem; background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); color: white; border-radius: 10px; margin-bottom: 2rem; }
.hero h1 { color: white; font-size: 2.5rem; margin-bottom: 1rem; }
.hero .subtitle { font-size: 1.1rem; opacity: 0.95; }

.intro-section { background: white; padding: 2rem; border-radius: 8px; margin-bottom: 2rem; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
.intro-section p { margin-bottom: 1rem; }

.video-section { margin-bottom: 3rem; }
.video-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 1.5rem; margin-top: 1rem; }
.video-card { background: white; padding: 1.5rem; border-radius: 8px; box-shadow: 0 2px 8px rgba(0,0,0,0.1); transition: transform 0.3s, box-shadow 0.3s; }
.video-card:hover { transform: translateY(-5px); box-shadow: 0 4px 15px rgba(0,0,0,0.2); }
.video-card h3 { margin-top: 0; font-size: 1.1rem; }
.video-card .meta { color: #7f8c8d; font-size: 0.9rem; margin: 0.5rem 0; }
.video-card .summary { font-size: 0.95rem; color: #555; line-height: 1.6; }

.page-header { text-align: center; padding: 2rem 1rem; background: white; border-radius: 8px; margin-bottom: 2rem; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
.page-header h1 { color: #2c3e50; }
.page-header p { color: #555; font-size: 1.05rem; margin-top: 1rem; }

.list-section { background: white; padding: 2rem; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
.list-item { padding: 1.5rem; border-bottom: 1px solid #eee; position: relative; }
.list-item:last-child { border-bottom: none; }
.list-item h3 { margin-top: 0; }
.list-item .meta { color: #7f8c8d; font-size: 0.9rem; margin: 0.5rem 0; }
.list-item .summary { color: #555; margin: 0.5rem 0; }
.list-item .tags { color: #95a5a6; font-size: 0.85rem; }
.list-item .rank { position: absolute; top: 1rem; right: 1rem; background: #e74c3c; color: white; padding: 0.3rem 0.6rem; border-radius: 5px; font-weight: bold; }
.list-item .date { position: absolute; top: 1rem; right: 1rem; color: #27ae60; font-size: 0.85rem; }
.list-item .topic-tag { display: inline-block; background: #3498db; color: white; padding: 0.2rem 0.5rem; border-radius: 3px; font-size: 0.8rem; margin-right: 0.5rem; }

.video-detail { background: white; padding: 2rem; border-radius: 8px; margin-bottom: 2rem; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
.video-detail h1 { color: #2c3e50; font-size: 2rem; margin-bottom: 1.5rem; }
.video-detail section { margin-bottom: 2rem; }
.video-detail .basic-info ul { list-style: none; }
.video-detail .basic-info li { padding: 0.5rem 0; border-bottom: 1px solid #eee; }
.video-detail .basic-info li:last-child { border-bottom: none; }
.video-detail .one-line p { font-size: 1.1rem; color: #2c3e50; font-weight: 500; font-style: italic; background: #ecf0f1; padding: 1rem; border-radius: 5px; }
.video-detail .summary p, .video-detail .review p { line-height: 1.8; color: #555; }

.related-section { background: white; padding: 2rem; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
.related-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1rem; margin-top: 1rem; }
.related-card { padding: 1rem; border: 1px solid #ddd; border-radius: 5px; transition: border-color 0.3s; }
.related-card:hover { border-color: #3498db; }
.related-card h4 { margin-top: 0; font-size: 1rem; }
.related-card .meta { color: #7f8c8d; font-size: 0.85rem; margin: 0.3rem 0; }
.related-card p { font-size: 0.9rem; color: #666; }

footer { text-align: center; padding: 2rem 1rem; color: #7f8c8d; background: white; margin-top: 2rem; border-radius: 8px; }

@media (max-width: 768px) {
  .hero h1 { font-size: 1.8rem; }
  .hero .subtitle { font-size: 1rem; }
  .video-grid { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: 1fr; }
  .container { padding: 1rem 0.5rem; }
}