/* 知识港湾增强样式 */
:root {
  --kh-primary: #4B8CD7;
  --kh-primary-hover: #3a7bc8;
  --kh-secondary: #EBF4FF;
  --kh-text-primary: #1e293b;
  --kh-text-secondary: #64748b;
  --kh-text-light: #94a3b8;
  --kh-border: #e2e8f0;
  --kh-bg: #f8fafc;
  --kh-shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
  --kh-shadow-md: 0 4px 16px rgba(75, 140, 215, 0.12);
  --kh-radius: 12px;
}

/* 知识港湾容器 */
.knowledge-hub {
  max-width: 1600px;
  margin: 0 auto;
  padding: 24px;
  width: 100%;
  box-sizing: border-box;
}

/* 区域标题 */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.section-header h2 {
  font-size: 22px;
  font-weight: 700;
  color: var(--kh-text-primary);
  position: relative;
  padding-left: 16px;
  margin: 0;
}

.section-header h2::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  height: 24px;
  width: 4px;
  background: var(--kh-primary);
  border-radius: 2px;
}

/* 课程卡片网格 */
.course-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

@media (max-width: 1024px) {
  .course-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .course-grid {
    grid-template-columns: 1fr;
  }
}

/* 课程卡片 */
.course-card {
  background: #fff;
  border-radius: var(--kh-radius);
  overflow: hidden;
  border: 1px solid var(--kh-border);
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
}

.course-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--kh-shadow-md);
  border-color: var(--kh-primary);
}

.course-card-image {
  height: 180px;
  background: var(--kh-secondary);
  overflow: hidden;
  position: relative;
}

.course-card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.course-card:hover .course-card-image img {
  transform: scale(1.05);
}

.course-card-body {
  padding: 20px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.course-card-tag {
  display: inline-block;
  padding: 4px 12px;
  font-size: 12px;
  font-weight: 500;
  color: var(--kh-primary);
  background: var(--kh-secondary);
  border-radius: 4px;
  margin-bottom: 12px;
  align-self: flex-start;
}

.course-card-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--kh-text-primary);
  margin-bottom: 12px;
  line-height: 1.4;
}

.course-card-desc {
  color: var(--kh-text-secondary);
  font-size: 14px;
  line-height: 1.6;
  margin-bottom: 16px;
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.course-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 14px;
}

.course-card-credit {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--kh-primary);
  font-weight: 500;
}

.course-card-lecturer {
  color: var(--kh-text-secondary);
}

.course-card-lecturer strong {
  color: var(--kh-text-primary);
  font-weight: 600;
}

/* 查看更多按钮 */
.view-more-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 32px;
  background: linear-gradient(135deg, var(--kh-primary) 0%, #5B9EFF 100%);
  color: white;
  border-radius: 24px;
  font-weight: 500;
  font-size: 15px;
  text-decoration: none;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(75, 140, 215, 0.3);
}

.view-more-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(75, 140, 215, 0.4);
}

.view-more-container {
  display: flex;
  justify-content: center;
  margin-top: 32px;
}

/* 热门文章区域 */
.popular-articles {
  margin-top: 48px;
}

.popular-articles .section-header {
  margin-bottom: 24px;
}

.more-articles {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--kh-primary);
  font-weight: 500;
  font-size: 14px;
  text-decoration: none;
  transition: all 0.3s ease;
}

.more-articles:hover {
  color: var(--kh-primary-hover);
}

.more-articles svg {
  width: 16px;
  height: 16px;
  transition: transform 0.3s ease;
}

.more-articles:hover svg {
  transform: translateX(4px);
}

/* 文章卡片优化 */
.article-cards {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.article-card.horizontal {
  display: flex;
  background: #fff;
  border-radius: var(--kh-radius);
  overflow: hidden;
  border: 1px solid var(--kh-border);
  transition: all 0.3s ease;
  height: 180px;
}

.article-card.horizontal:hover {
  transform: translateY(-4px);
  box-shadow: var(--kh-shadow-md);
  border-color: var(--kh-primary);
}

.article-card.horizontal .article-content {
  flex: 1;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-width: 0;
}

.article-card.horizontal .vertical-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--kh-text-primary);
  margin-bottom: 10px;
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-card.horizontal p {
  font-size: 14px;
  color: var(--kh-text-secondary);
  line-height: 1.6;
  margin-bottom: 10px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-card.horizontal .article-meta {
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--kh-text-light);
  margin-bottom: 10px;
}

.article-card.horizontal .article-meta i {
  color: var(--kh-primary);
  margin-right: 4px;
}

.article-card.horizontal .read-more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--kh-primary);
  font-size: 14px;
  font-weight: 500;
  transition: all 0.3s ease;
}

.article-card.horizontal .read-more:hover {
  color: var(--kh-primary-hover);
}

.article-card.horizontal .read-more i {
  transition: transform 0.3s ease;
}

.article-card.horizontal:hover .read-more i {
  transform: translateX(4px);
}

.article-card.horizontal .article-image {
  flex: 0 0 240px;
  width: 240px;
  height: 180px;
  overflow: hidden;
}

.article-card.horizontal .article-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.article-card.horizontal:hover .article-image img {
  transform: scale(1.05);
}

/* 分页优化 */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-top: 32px;
  font-size: 14px;
  color: var(--kh-text-secondary);
}

.pagination a {
  padding: 8px 16px;
  background: var(--kh-secondary);
  color: var(--kh-primary);
  border-radius: 6px;
  font-weight: 500;
  text-decoration: none;
  transition: all 0.3s ease;
}

.pagination a:hover {
  background: var(--kh-primary);
  color: white;
}

/* 空状态 */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 60px 40px;
  text-align: center;
  background: linear-gradient(135deg, #f8fafc 0%, #EBF4FF 100%);
  border-radius: var(--kh-radius);
  border: 1px solid var(--kh-border);
}

.empty-state i {
  font-size: 48px;
  color: var(--kh-primary);
  opacity: 0.5;
  margin-bottom: 16px;
}

.empty-state h3 {
  font-size: 18px;
  font-weight: 600;
  color: var(--kh-text-primary);
  margin: 0 0 8px 0;
}

.empty-state p {
  color: var(--kh-text-secondary);
  font-size: 14px;
  margin: 0;
}

/* 响应式 */
@media (max-width: 768px) {
  .knowledge-hub {
    padding: 20px 16px;
  }
  
  .article-card.horizontal {
    flex-direction: column;
    height: auto;
  }
  
  .article-card.horizontal .article-image {
    width: 100%;
    height: 160px;
    order: -1;
  }
  
  .article-card.horizontal .article-content {
    padding: 16px;
  }
}