.collapsible {
  background-color: #999;
  color: white;
  cursor: pointer;
  padding: 16px;
  width: 80%;
  border: none;
  text-align: left;
  outline: 2;
  font-size: 16px;
}

.active, .collapsible:hover {
  background-color: #666;
}

.content {
  padding: 0 18px;
  display: none;
  overflow: hidden;
  background-color: #f3f3f3;
}