JSFiddle - React, Tailwind, and code Playground

HTML

<div id="top"></div>
<div id="bottom"></div>

CSS

body {
    background: #EEE;
}
#top {
    height: 10px;
    border-top-left-radius: 40% 10px;
    border-top-right-radius: 40% 10px;
    background: -webkit-linear-gradient( top, #EEE, #DDD );
    /*box-shadow: inset 0 -3px 5px #CCC;*/
}
#bottom {
    height: 30px;
    width: 75%;
    margin: auto;
    border-bottom-left-radius: 40% 30px;
    border-bottom-right-radius: 40% 30px;
    background: -webkit-radial-gradient(top, ellipse cover, #FFF 0%, #EEE 80%);
    /*box-shadow: inset 0 10px 20px #FFF;*/
}