.collapsible {
  cursor: pointer;
  border: none;
  text-align: left;
  outline: none;
}

/*.active, .collapsible:hover {
  background-color: #555;
}
*/
.collapsible_content {
  padding: 0 18px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.2s ease-out;
  background-color: #f1f1f1;
}