.reveal-if-active {
  opacity: 0;
  max-height: 0;
  overflow: hidden;
  transition: 0.5s;
  input[type="radio"]:checked ~ &,
  input[type="checkbox"]:checked ~ & {
    opacity: 1;
    max-height: 100px;
    overflow: visible;
    padding: 10px 20px;
    transform: scale(1);
  }
}