/* 章节项目 */
.chapter-item {
  border: 1px solid rgba(30, 78, 216, 0.2);
  border-radius: 0.75rem;
  overflow: hidden;
  margin-bottom: 1rem;
}

/* 章节标题按钮 */
.chapter-header {
  width: 100%;
  padding: 1.25rem 1.5rem;
  background: linear-gradient(to right, var(--primary-lighter), var(--primary-light));
  border: none;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: none;
  position: relative;
  z-index: 10;
}

.chapter-header h3 {
  margin: 0;
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--gray-800);
  flex: 1;
}

.chapter-header i {
  color: var(--primary-color);
  font-size: 0.875rem;
  transition: none;
  margin-left: 1rem;
}

.chapter-header.active i {
  transform: rotate(180deg);
}

/* 章节内容 */
.chapter-content {
  padding: 0;
  overflow: hidden;
  max-height: 0;
  transition: none;
}

.chapter-item.active .chapter-content {
  padding: 1.5rem;
  max-height: 1000px;
}

/* 课程链接网格 */
.lessons-grid {
  display: grid;
  grid-template-columns: repeat(1, minmax(0, 1fr));
  gap: 1rem;
}

@media (min-width: 640px) {
  .lessons-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1024px) {
  .lessons-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* 课程链接 */
.lesson-link {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background-color: var(--primary-color);
  color: white;
  text-decoration: none;
  border-radius: 0.5rem;
  font-weight: 500;
  transition: none;
}

.lesson-link:hover {
  /* 移除动态效果 */
}