.radio-if-active {
  opacity: 0;
  max-height: 0;
  overflow: hidden;
  font-size: 16px;
  transform: scale(0.8);
  transition: .3s;
}

input[type="radio"]:checked + .radio-if-active,
input[type="radio"]:checked + label + .radio-if-active {
  opacity: 1;
  max-height: 100px;
  padding: 10px 20px;
  transform: scale(1);
  overflow: visible;
}