JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>One</li>
    <li>Two</li>
    <li>Three</li>
    <li>Four</li>
</ul>

CSS

ul {
    display: table;
    width: 400px;
    border: solid 1px black;
    padding: 0;
}

li {
    display: table-cell;
    position: relative;
    text-align: center;
}

li:after {
    content: ' ';
    position: absolute;
    height: 100%;
    width: 1px;
    background: blue;
    margin-left: 33.3%;
}

li:last-child:after {
    content: none;
}