JSFiddle - React, Tailwind, and code Playground

HTML

<div id="ou">
<div id="he"></div>
<div id="con">some data here.................................</div>
</div>
<div id="fo"></div>

CSS

* {
    margin: 0;
}
html, body {
    height: 100%;
}
#ou {
    position:relative;
    background-color:grey;
    min-height: 100%;
    height: auto !important;
    height: 100%;
    width:400px;
    margin: 0 auto -30px; /* the bottom margin is the negative value of the footer's height */
}
#he
{
    height:30px;
    background-color:red;
}
#fo{
    background-color:yellow;
    height: 30px; /* .push must be the same height as .footer */
    position:relative;
    width:400px;
    margin:0 auto;
}