.card {
  border: 1px solid #ddd;
  padding: 20px;
  cursor: pointer;
  transition: 0.3s;
}

.card-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease;
}

.card.active .card-content {
  max-height: 300px;
}