JSFiddle - React, Tailwind, and code Playground

HTML

<main>
  hello
</main>

<footer>
    i am the footer
</footer>

CSS

html, body {
    height: 100%;
}
main {
    min-height: 100%;
    margin-bottom: -100px;
    background: #ddd;
}
main:after {
    content: "";
    display: block;
    height: 100px;
}
footer {
    height: 100px;
    background: #eee;
}