JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

div {
    width: 60%;
    height: 200px;
    margin: 200px auto 0;
    background: red;
}

div:before {
    content: "";
    position: absolute;
    width: 100%;
    height: 100px;
    left: 0;
    margin-top: 50px;
    background: blue;
}