JSFiddle - React, Tailwind, and code Playground

HTML

<div>
  hi
</div>

CSS

div {
	border-top: 100px solid blue;
	border-left: 50px solid transparent;
	border-right: 50px solid transparent;
	height: 0;
	width: 100px;
  position: relative;
}

div:before {
  position: absolute;
  top:0;
  height:0;
  width: 100%;
}