/* Reset & Base */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #f5f5f5;
}

a {
  text-decoration: none;
  color: #0066cc;
  transition: color 0.3s;
}

a:hover {
  color: #004499;
}

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Header & Navigation */
.site-header {
  background: #fff;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  min-height: 60px;
}

.site-logo {
  font-size: 24px;
  font-weight: bold;
  color: #222;
}

.site-logo:hover {
  color: #0066cc;
}

.main-nav {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  gap: 5px;
}

.main-nav a {
  padding: 8px 15px;
  color: #555;
  white-space: nowrap;
  transition: all 0.3s;
}

.main-nav a:hover,
.main-nav a.active {
  color: #0066cc;
  background: rgba(0,102,204,0.1);
  border-radius: 4px;
}

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

/* Page Header */
.page-header {
  background: #fff;
  padding: 40px 30px;
  margin-bottom: 30px;
  border-radius: 8px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.page-header h1 {
  font-size: 32px;
  color: #222;
  margin-bottom: 15px;
  line-height: 1.3;
}

.page-intro {
  font-size: 16px;
  color: #666;
  line-height: 1.8;
  margin-top: 20px;
}

/* Section */
section {
  background: #fff;
  padding: 30px;
  margin-bottom: 30px;
  border-radius: 8px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.section-title {
  font-size: 24px;
  color: #222;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid #0066cc;
}

.section-desc {
  color: #666;
  margin-bottom: 20px;
  line-height: 1.8;
}

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

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

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.12);
  border-color: #0066cc;
}

.video-card h3 {
  font-size: 18px;
  color: #222;
  margin-bottom: 10px;
}

.video-card h3 a {
  color: #222;
}

.video-card h3 a:hover {
  color: #0066cc;
}

.video-meta {
  font-size: 14px;
  color: #999;
  margin-bottom: 10px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.video-meta span {
  display: inline-block;
}

.video-desc {
  font-size: 14px;
  color: #666;
  line-height: 1.6;
  margin-bottom: 10px;
}

.video-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.tag {
  display: inline-block;
  padding: 4px 10px;
  background: #f0f0f0;
  color: #666;
  font-size: 12px;
  border-radius: 3px;
}

/* Detail Page */
.video-detail-header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  padding: 50px 30px;
  margin-bottom: 30px;
  border-radius: 8px;
}

.video-detail-header h1 {
  font-size: 36px;
  margin-bottom: 20px;
  text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.video-detail-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  font-size: 16px;
  opacity: 0.95;
}

.detail-section {
  background: #fff;
  padding: 30px;
  margin-bottom: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.detail-section h2 {
  font-size: 22px;
  color: #222;
  margin-bottom: 15px;
  padding-left: 12px;
  border-left: 4px solid #0066cc;
}

.detail-section p {
  color: #555;
  line-height: 1.8;
  margin-bottom: 15px;
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 15px;
  margin-bottom: 20px;
}

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

.info-item strong {
  color: #666;
  display: block;
  margin-bottom: 5px;
  font-size: 14px;
}

.info-item span {
  color: #222;
  font-size: 15px;
}

/* Related List */
.related-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 15px;
}

.related-item {
  border: 1px solid #e0e0e0;
  padding: 15px;
  border-radius: 6px;
  transition: all 0.3s;
}

.related-item:hover {
  border-color: #0066cc;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.related-item h4 {
  font-size: 16px;
  margin-bottom: 8px;
}

.related-item h4 a {
  color: #222;
}

.related-item h4 a:hover {
  color: #0066cc;
}

.related-item p {
  font-size: 13px;
  color: #666;
  line-height: 1.5;
}

/* Footer */
.site-footer {
  background: #222;
  color: #999;
  padding: 30px 20px;
  margin-top: 50px;
  text-align: center;
}

.site-footer p {
  margin: 5px 0;
}

/* Responsive */
@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    padding: 10px 15px;
    gap: 10px;
  }

  .site-logo {
    font-size: 20px;
  }

  .main-nav {
    width: 100%;
    justify-content: space-between;
    gap: 0;
  }

  .main-nav a {
    flex: 1 1 0;
    min-width: 0;
    padding: 8px 5px;
    font-size: 13px;
    text-align: center;
    overflow: hidden;
    text-overflow: ellipsis;
  }

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

  .page-header h1 {
    font-size: 24px;
  }

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

  .video-detail-header {
    padding: 30px 20px;
  }

  .video-detail-header h1 {
    font-size: 26px;
  }

  .video-detail-meta {
    font-size: 14px;
    gap: 12px;
  }

  section {
    padding: 20px;
  }
}

/* UI Style Variants */
.ui-style-0 { --primary: #0066cc; --secondary: #004499; }
.ui-style-1 { --primary: #e63946; --secondary: #a4161a; }
.ui-style-2 { --primary: #2a9d8f; --secondary: #1d7567; }
.ui-style-3 { --primary: #e76f51; --secondary: #b85a3f; }
.ui-style-4 { --primary: #8338ec; --secondary: #5a189a; }
.ui-style-5 { --primary: #06aed5; --secondary: #048ba8; }
.ui-style-6 { --primary: #f72585; --secondary: #b5179e; }
.ui-style-7 { --primary: #4361ee; --secondary: #3a0ca3; }
.ui-style-8 { --primary: #f77f00; --secondary: #d36a00; }
.ui-style-9 { --primary: #06d6a0; --secondary: #05b389; }
.ui-style-10 { --primary: #ef476f; --secondary: #d62d56; }
.ui-style-11 { --primary: #118ab2; --secondary: #0d6f8f; }
.ui-style-12 { --primary: #ffd60a; --secondary: #d4af37; }
.ui-style-13 { --primary: #00b4d8; --secondary: #0096c7; }
.ui-style-14 { --primary: #9d4edd; --secondary: #7b2cbf; }
.ui-style-15 { --primary: #219ebc; --secondary: #1a7a94; }