JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

DIV {
    border-bottom: 40px solid red;
    border-left: 40px solid green;
    border-right: 40px solid blue;
    border-top: 40px solid yellow;
    height: 0;
    width: 0;
    font-size: 0px;
}