JSFiddle - React, Tailwind, and code Playground

HTML

<p>Div with radial-gradient(100px 40px, 5em 40px, white, black);</p>
<div id="example"></div>
<p>For the syntax, see <a href="http://dev.w3.org/csswg/css3-images/#radial-gradient-syntax">http://dev.w3.org/csswg/css3-images/#radial-gradient-syntax</a> under "Explicitly".</p>

CSS

#example {
    border:1px solid black;
    height:80px;
    width:200px;
    background-image: radial-gradient(100px 40px, 5em 40px, white, black);
}