show-on-sibling-focus.css

/* Show an item only when an item within the parenthas focus */
.show-on-focus-parent:focus-within .show-on-focus-child {
  opacity: 1;
  max-height: 200px; 
  visibility: visible;
  transform: translateY(0);
  transition: all 0.2s ease-in-out;
}

.show-on-focus-child {
  opacity: 0;
  max-height: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.2s ease-in-out;
}