/* 内联基础样式 */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  color: #333;
  background: #f5f5f5;
}
a { color: #0066cc; text-decoration: none; }
a:hover { text-decoration: underline; }
ul, ol { list-style: none; }

/* 顶部导航 */
.header {
  background: #fff;
  border-bottom: 1px solid #e0e0e0;
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: #0066cc;
  white-space: nowrap;
}
.nav {
  display: flex;
  gap: 1.5rem;
  align-items: center;
  flex-wrap: nowrap;
}
.nav a {
  white-space: nowrap;
  font-size: 0.95rem;
}

/* 移动端导航 - 单行不换行 */
@media (max-width: 768px) {
  .header-inner {
    flex-direction: column;
    gap: 0.75rem;
  }
  .logo {
    font-size: 1.25rem;
  }
  .nav {
    width: 100%;
    display: flex;
    flex-wrap: nowrap;
    justify-content: space-between;
    align-items: center;
    gap: 0.25rem;
    overflow: visible;
  }
  .nav a {
    flex: 1 1 0;
    min-width: 0;
    text-align: center;
    font-size: 0.8rem;
    padding: 0.25rem 0.125rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
}

/* 主容器 */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

/* 标题样式 */
h1 {
  font-size: 2rem;
  margin-bottom: 1.5rem;
  color: #222;
  line-height: 1.3;
}
h2 {
  font-size: 1.5rem;
  margin: 2rem 0 1rem;
  color: #333;
}
h3 {
  font-size: 1.25rem;
  margin: 1.5rem 0 0.75rem;
  color: #444;
}

/* 段落与列表 */
p {
  margin-bottom: 1rem;
  line-height: 1.8;
}
.intro {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

/* 卡片列表 */
.section {
  margin-bottom: 3rem;
}
.video-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-top: 1rem;
}
.video-card {
  background: #fff;
  border-radius: 8px;
  padding: 1.25rem;
  box-shadow: 0 2px 6px rgba(0,0,0,0.08);
  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 {
  margin: 0 0 0.75rem;
  font-size: 1.1rem;
}
.video-meta {
  font-size: 0.85rem;
  color: #666;
  margin-bottom: 0.5rem;
}
.video-desc {
  font-size: 0.9rem;
  color: #555;
  line-height: 1.6;
}
.video-link {
  display: inline-block;
  margin-top: 0.75rem;
  color: #0066cc;
  font-weight: 500;
}

/* 详情页 */
.detail-header {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}
.detail-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
  padding: 1rem;
  background: #f9f9f9;
  border-radius: 6px;
}
.meta-item {
  font-size: 0.9rem;
}
.meta-label {
  font-weight: bold;
  color: #555;
}
.detail-content {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  box-shadow: 0 1px 4px rgba(0,0,0,0.08);
}
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}
.tag {
  display: inline-block;
  background: #e3f2fd;
  color: #1976d2;
  padding: 0.25rem 0.75rem;
  border-radius: 16px;
  font-size: 0.85rem;
}

/* 响应式 */
@media (max-width: 768px) {
  .container { padding: 1rem; }
  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }
  .video-list { grid-template-columns: 1fr; }
  .detail-header, .detail-content { padding: 1.25rem; }
}

/* UI风格变体 */
.ui-style-0 body { background: #fafafa; }
.ui-style-1 body { background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%); }
.ui-style-2 .header { background: linear-gradient(90deg, #667eea 0%, #764ba2 100%); color: #fff; }
.ui-style-2 .logo, .ui-style-2 .nav a { color: #fff; }
.ui-style-3 .video-card { border-left: 4px solid #0066cc; }
.ui-style-4 body { background: #fff; }
.ui-style-5 .video-card:hover { border: 2px solid #0066cc; }
.ui-style-6 h1, .ui-style-6 h2 { border-bottom: 2px solid #0066cc; padding-bottom: 0.5rem; }
.ui-style-7 .header { background: #2c3e50; }
.ui-style-7 .logo, .ui-style-7 .nav a { color: #ecf0f1; }
.ui-style-8 body { background: #eceff1; }
.ui-style-9 .video-card { box-shadow: 0 4px 8px rgba(0,102,204,0.15); }
.ui-style-10 body { font-family: Georgia, serif; }
.ui-style-11 .container { max-width: 1400px; }
.ui-style-12 .video-list { gap: 2rem; }
.ui-style-13 .header { border-bottom: 3px solid #0066cc; }
.ui-style-14 body { line-height: 1.8; }
.ui-style-15 .video-card { border-radius: 12px; }