JSFiddle - React, Tailwind, and code Playground

HTML

<main>main</main>
<footer>footer</footer>

CSS

html {
 height: 100%;
}
body {
    margin: 0;
    min-height: 100%;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;
    -ms-flex-direction: column;
    -webkit-flex-direction: column;
    flex-direction: column;
}

footer {
    background: silver;
    /* height: 200px; */
    margin-top: auto;
}