JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <span></span>
</div>

CSS

div {
    width: 300px;
    height: 300px;
    border: 2px solid #000;
    position: relative;
}

span {
    position: absolute;
    width: 100px;
    height: 100px;
    background: yellow;
    right: 0;
    bottom: 0;
}