JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

div {
    position:absolute;
    top:100px;
    width:0; 
    height:0; 
    border:100px solid rgba(0,0,0,0); 
    border-top-color:#333;
    -webkit-transform:rotate(45deg);
    -moz-transform:rotate(45deg);
    transform:rotate(45deg);
}