JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="nav">
	<li></li>
	<li></li>
	<li></li>
	<li></li>
</ul>

CSS

ul.nav {
    text-align: justify;
    position: relative;
    border: 1px solid red;

    padding: 0;
    margin: 0;
    height:31px;
}

ul.nav li {
    display: inline-block;
    position: relative;
    border: 1px solid green;
    margin: 0;
    padding: 5px;
    background: gray;
    width: 20px;
    height: 20px;
}


ul.nav:before{
    content: '';
    display: block;
    width: 100%;
    height: 0;
}

ul.nav:after {
    width: 100%;
    height: 0;
    visibility: hidden;
    overflow: hidden;
    content: '';
    display: inline-block;
}