JSFiddle - React, Tailwind, and code Playground

HTML

<div>
</div>

CSS

div{
	position: absolute;
	left:0px; 
	top:0px;
	width: 0;
	height: 0; 
	border-left: 5px solid transparent; 
	border-right: 5px solid transparent; 
	border-bottom: 10px solid red;
}