JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box"></div>

CSS

#box {
    width: 300px;
    height: 100px;
    position: relative;
    overflow: hidden;
}
#box:before {
    content:' ';
    position:absolute;
    width:80px;
    height:80px;
    top:70px;
    left:250px;
    border-radius:100%;
    box-shadow:0 0 0 1000px green;
}