JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <link rel="stylesheet" href="style.css">
    </head>
    <body>
        <div class="wrapper">
                
        </div>
        <footer>
            Footer<br>
        </footer>
    </body>
<html>

CSS

html, body {
    height: 100%;
    background-color: grey;
    padding:0;
    margin:0;
}
.wrapper {
    min-height: 100%;
    margin-bottom: -20%;
    padding-bottom: -20%;
    background-color: green;
}
footer {
    background-color: blue;
    min-height: 20%;
    position: absolute;
    bottom: 0;
    width: 100%;
}