JSFiddle - React, Tailwind, and code Playground

HTML

<div id="top" style="height:50px;"></div>
<div id="top" style="height:50px; background-color: red;"></div>
<div id="bottom" style="background:lightgrey;"></div>

CSS

body, html {
    height: 100%;
    overflow: hidden;
    margin: 0;
}
div:last-child {
    height: 100%;
}