JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
<li>a</li>
<li>a</li>
<li>a</li>
<li>a</li>
</ul>

CSS

ul li {
  line-height: 30px;
  height: 30px;
  list-style: none;
  width: 50px;
  display: inline-block;
  text-align: center;
}
ul li:not(:last-child) {
  border-right: 1px solid green;
}