JSFiddle - React, Tailwind, and code Playground

HTML

<div id="oval"></div>

CSS

#oval {
	width: 90vw;
	height: 90vh;
	background: -moz-linear-gradient(top,  rgba(193,193,193,1) 0%, rgba(255,255,255,0) 100%);
background: -webkit-linear-gradient(top,  rgba(193,193,193,1) 0%,rgba(255,255,255,0) 100%);
background: linear-gradient(to bottom,  rgba(193,193,193,1) 0%,rgba(255,255,255,0) 100%);
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#c1c1c1', endColorstr='#00ffffff',GradientType=0 );

	
	border-radius: 40% 40% 0 0;
}