JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outer">
    <label id="inner"></label>
</div>

CSS

#outer {
    width500px;
    height:200px;
    background:green;
    position:relative;
}

#inner {
    width:100%;
    height:50px;
    background:blue;
    bottom:0px;
    position:absolute;
}