JSFiddle - React, Tailwind, and code Playground

HTML

<div class="modalOverlay">Press ESC to hide me.</div>

CSS

.modalOverlay {
  width: 200px;
  height: 200px;
  opacity: 0.8;
  background-color: black;
  visibility: visible;
}

JavaScript

document.addEventListener("keydown", hideModalKeyPress, false);
function hideModalKeyPress(e) {
	if(e.keyCode === 27)
	{
		document.getElementsByClassName('modalOverlay')[0].style.visibility = "hidden";
	}
}