* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
  line-height: 1.6;
  color: #333;
  background: linear-gradient(135deg, #f5f7fa 0%, #e8ecf1 100%);
}

body.ui-style-5 {
  --primary-color: #2563eb;
  --secondary-color: #1e40af;
  --accent-color: #3b82f6;
  --text-color: #1f2937;
  --light-bg: #f3f4f6;
  --border-color: #e5e7eb;
}

a {
  color: var(--primary-color, #2563eb);
  text-decoration: none;
  transition: all 0.3s ease;
}

a:hover {
  color: var(--accent-color, #3b82f6);
  text-decoration: underline;
}

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

header {
  background: linear-gradient(135deg, #1e3a8a 0%, #1e40af 100%);
  color: white;
  padding: 20px 0;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 15px;
}

.logo {
  font-size: 28px;
  font-weight: 700;
  color: white;
  letter-spacing: 2px;
}

nav {
  display: flex;
  flex-wrap: nowrap;
  justify-content: space-between;
  align-items: center;
  gap: 5px;
}

nav a {
  color: white;
  padding: 8px 15px;
  border-radius: 6px;
  white-space: nowrap;
  font-size: 15px;
  flex: 1 1 0;
  min-width: 0;
  text-align: center;
  overflow: hidden;
  text-overflow: ellipsis;
}

nav a:hover {
  background: rgba(255,255,255,0.2);
  text-decoration: none;
}

main {
  padding: 40px 0;
  min-height: calc(100vh - 300px);
}

section {
  background: white;
  border-radius: 12px;
  padding: 30px;
  margin-bottom: 30px;
  box-shadow: 0 2px 16px rgba(0,0,0,0.08);
}

h1 {
  font-size: 32px;
  color: var(--text-color, #1f2937);
  margin-bottom: 20px;
  padding-bottom: 15px;
  border-bottom: 3px solid var(--primary-color, #2563eb);
}

h2 {
  font-size: 24px;
  color: var(--text-color, #1f2937);
  margin-bottom: 20px;
  padding-left: 12px;
  border-left: 4px solid var(--primary-color, #2563eb);
}

.intro-text {
  font-size: 16px;
  line-height: 1.8;
  color: #4b5563;
  text-align: justify;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
  margin-top: 20px;
}

.video-card {
  background: linear-gradient(135deg, #ffffff 0%, #f9fafb 100%);
  border-radius: 10px;
  padding: 20px;
  transition: all 0.3s ease;
  border: 1px solid #e5e7eb;
}

.video-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.15);
  border-color: var(--primary-color, #2563eb);
}

.video-card h3 {
  font-size: 18px;
  margin-bottom: 10px;
  color: var(--text-color, #1f2937);
}

.video-card h3 a {
  color: var(--text-color, #1f2937);
}

.video-card h3 a:hover {
  color: var(--primary-color, #2563eb);
}

.video-meta {
  font-size: 14px;
  color: #6b7280;
  margin: 8px 0;
}

.video-meta span {
  margin-right: 12px;
  display: inline-block;
}

.video-desc {
  font-size: 14px;
  color: #4b5563;
  line-height: 1.6;
  margin-top: 10px;
}

.video-list {
  list-style: none;
}

.video-list li {
  border-bottom: 1px solid #e5e7eb;
  padding: 15px 0;
}

.video-list li:last-child {
  border-bottom: none;
}

.detail-info {
  background: #f9fafb;
  border-radius: 8px;
  padding: 20px;
  margin: 20px 0;
}

.detail-info p {
  margin: 10px 0;
  line-height: 1.8;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 15px 0;
}

.tag {
  background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
  color: var(--primary-color, #2563eb);
  padding: 5px 12px;
  border-radius: 20px;
  font-size: 13px;
  border: 1px solid #93c5fd;
}

footer {
  background: linear-gradient(135deg, #1f2937 0%, #111827 100%);
  color: white;
  text-align: center;
  padding: 30px 0;
  margin-top: 50px;
}

.link-list {
  display: flex;
  flex-wrap: wrap;
  gap: 15px;
  justify-content: center;
  margin: 20px 0;
}

.link-list a {
  color: #93c5fd;
  font-size: 14px;
}

@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
  }
  
  nav {
    width: 100%;
    flex-wrap: nowrap !important;
    justify-content: space-between;
    gap: 3px;
  }
  
  nav a {
    font-size: 13px;
    padding: 6px 8px;
    flex: 1 1 0;
    min-width: 0;
  }
  
  .video-grid {
    grid-template-columns: 1fr;
  }
  
  h1 {
    font-size: 24px;
  }
  
  h2 {
    font-size: 20px;
  }
  
  section {
    padding: 20px;
  }
}

@media (max-width: 480px) {
  nav a {
    font-size: 12px;
    padding: 5px 5px;
  }
  
  .logo {
    font-size: 22px;
  }
}