/* 基础样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'PingFang SC', 'Microsoft YaHei', Arial, sans-serif;
  line-height: 1.8;
  background: linear-gradient(135deg, #f5f7fa 0%, #e8ecf1 100%);
  color: #2c3e50;
}

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

/* 头部导航 */
header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  box-shadow: 0 2px 15px rgba(102, 126, 234, 0.3);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 0;
}

.logo {
  font-size: 26px;
  font-weight: 700;
  color: #fff;
  text-decoration: none;
  letter-spacing: 1px;
  text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

nav ul {
  display: flex;
  flex-wrap: nowrap;
  list-style: none;
  gap: 8px;
}

nav a {
  color: #fff;
  text-decoration: none;
  padding: 10px 18px;
  border-radius: 25px;
  transition: all 0.3s ease;
  font-weight: 500;
  background: rgba(255,255,255,0.1);
  white-space: nowrap;
  font-size: 15px;
}

nav a:hover {
  background: rgba(255,255,255,0.25);
  transform: translateY(-2px);
}

/* 主内容区域 */
main {
  padding: 40px 0;
  min-height: calc(100vh - 200px);
}

.page-title {
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 30px;
  color: #2c3e50;
  text-align: center;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.intro {
  background: #fff;
  padding: 35px;
  border-radius: 15px;
  margin-bottom: 45px;
  box-shadow: 0 5px 20px rgba(0,0,0,0.08);
  line-height: 2;
  font-size: 16px;
  color: #555;
}

section {
  margin-bottom: 50px;
}

.section-title {
  font-size: 28px;
  font-weight: 600;
  margin-bottom: 25px;
  color: #2c3e50;
  padding-left: 15px;
  border-left: 5px solid #667eea;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 25px;
}

.video-card {
  background: #fff;
  border-radius: 12px;
  padding: 25px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.08);
  transition: all 0.3s ease;
  border: 1px solid transparent;
}

.video-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(102, 126, 234, 0.2);
  border-color: #667eea;
}

.video-title {
  font-size: 19px;
  font-weight: 600;
  margin-bottom: 12px;
  color: #2c3e50;
  line-height: 1.5;
}

.video-title a {
  color: #2c3e50;
  text-decoration: none;
  transition: color 0.3s ease;
}

.video-title a:hover {
  color: #667eea;
}

.video-meta {
  font-size: 14px;
  color: #7f8c8d;
  margin-bottom: 10px;
  display: flex;
  gap: 15px;
  flex-wrap: wrap;
}

.video-meta span {
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.video-desc {
  font-size: 15px;
  color: #666;
  line-height: 1.8;
  margin-top: 12px;
}

.video-link {
  display: inline-block;
  margin-top: 15px;
  padding: 8px 20px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  text-decoration: none;
  border-radius: 20px;
  font-size: 14px;
  transition: all 0.3s ease;
  font-weight: 500;
}

.video-link:hover {
  transform: translateX(5px);
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

/* 列表样式 */
.video-list {
  background: #fff;
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.video-item {
  padding: 20px 0;
  border-bottom: 1px solid #ecf0f1;
}

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

/* 详情页 */
.detail-header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  padding: 50px 0;
  margin-bottom: 40px;
  border-radius: 15px;
  box-shadow: 0 5px 20px rgba(102, 126, 234, 0.3);
}

.detail-header h1 {
  font-size: 38px;
  margin-bottom: 20px;
  text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.detail-meta {
  display: flex;
  gap: 25px;
  flex-wrap: wrap;
  font-size: 16px;
  opacity: 0.95;
}

.detail-content {
  background: #fff;
  padding: 40px;
  border-radius: 15px;
  box-shadow: 0 5px 20px rgba(0,0,0,0.08);
  margin-bottom: 40px;
}

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

.detail-section h2 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 15px;
  color: #2c3e50;
  padding-left: 12px;
  border-left: 4px solid #667eea;
}

.detail-section p, .detail-section ul {
  font-size: 16px;
  line-height: 2;
  color: #555;
}

.tags {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 10px;
}

.tag {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  padding: 6px 15px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 500;
}

/* 底部 */
footer {
  background: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
  color: #ecf0f1;
  text-align: center;
  padding: 35px 0;
  margin-top: 60px;
}

/* 响应式 - 移动端单行导航 */
@media (max-width: 768px) {
  nav ul {
    justify-content: space-between;
    gap: 4px;
    width: 100%;
  }

  nav a {
    flex: 1 1 0;
    min-width: 0;
    padding: 8px 6px;
    font-size: 13px;
    text-align: center;
    overflow: hidden;
    text-overflow: ellipsis;
  }

  .header-content {
    flex-direction: column;
    gap: 15px;
  }

  nav {
    width: 100%;
  }

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

  .page-title {
    font-size: 28px;
  }

  .detail-header h1 {
    font-size: 28px;
  }
}

@media (max-width: 480px) {
  nav a {
    font-size: 12px;
    padding: 6px 4px;
  }
}