JSFiddle - React, Tailwind, and code Playground

HTML

<div class="angle"></div>

CSS

.angle {
    position: relative;
	width: 0; 
	height: 0; 
	border-left: 100px solid transparent;
	border-right: 100px solid transparent;
	border-bottom: 100px solid blue;
}

.angle:after {
    position: absolute;
    content: "";
    top: 0;
    left: 50%;
    margin-left: -60px;
	width: 0; 
	height: 0; 
	border-left: 60px solid transparent;
	border-right: 60px solid transparent;
	border-bottom: 60px solid black;
}