JSFiddle - React, Tailwind, and code Playground

HTML

<div id="radial"></div>

CSS

div {
    width: 60%;
    height: 300px;
    background: red;
    
    }

JavaScript

rada=document.getElementById('radial');
window.onload=window.onresize=function() {
rada.style.borderRadius=(rada.offsetWidth-rada.offsetHeight)+"px";
}