JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper-with-intrinsic-ratio">
  <div class="element-to-stretch"></div>
</div>

CSS

.wrapper-with-intrinsic-ratio {
	position: relative;
	padding-bottom: 20%;
	height: 0;
}
.element-to-stretch {
	position: absolute;
	top: 0;
	left: 0;
	width: 100%;
	height: 100%;
	background: teal;	
}