JSFiddle - React, Tailwind, and code Playground

HTML

<div class="top">top</div>
<div class="bottom">bottom</div>

CSS

html, body{
    height:100%;
}
.top{
    height:100%;
    background:red;
}
.bottom{
    position:absolute;
    height:100px;
    background:green;
    bottom:0;
    width:100%;
}