.collapsible {
  background-color: #eeeeee;
  color: dark;
  cursor: pointer;
  padding: 0px;
  width: 40px;
  height: 40px;
  border: none;
  text-align: center;
  outline: none;
  font-size: 15px;
}

.col-active, .collapsible:hover {
  background-color: #aaaaaa;
  color: white;
}

.collapsible:after {
  content: '\002B';
  color: dark;
  font-weight: bold;
  float: center;
  margin-left: 0px;
}

.col-active:after {
  content: "\2212";
  color: white;
}

.content {
  padding: 0 18px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.25s ease-out;
  background-color: #eeeeee;
}