JSFiddle - React, Tailwind, and code Playground

HTML

<header></header>
<div class='content'>
    <nav></nav>
    <article></article>
</div>
<footer>Я ФУТОР</footer>

CSS

* {
    margin:0;
    padding:0;
}
header {
    height:50px;
    background-color: orange;
}
nav {
    width:20%;
    float:left;
    height:60px;
    background-color: silver;
}
article {
    float:left;
    width:80%;
    background-color:gray;
    height:80px;
}
.content:after {
    content:'';
    display:table;
    clear:both;
}
footer {
    position:fixed;
    bottom: 0;
    width: 100%;
    height:50px;
    background-color:black;
    font-family: sans-serif;
    line-height:50px;
    color:white;
}