JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
    <h1>Тут контент</h1>
    <div class="push"></div>    
</div>
<div class="footer">
    Футер
</div>

CSS

* {
    margin: 0;
}
html, body {
    height: 100%;
}
.wrapper {
    min-height: 100%;
    height: auto !important; /* This line and the next line are not necessary unless you need IE6 support */
    height: 100%;
    margin: 0 auto -55px; /* the bottom margin is the negative value of the footer's height */
}
.footer, .push {
    height: 55px; /* .push must be the same height as .footer */
}

.footer
{
    background: rgba(255,0,0,0.2);
}