JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
<li><a href="#">item1</a></li>
<li><a href="#">item1</a></li>
<li><a href="#">item1</a></li>
<li><a href="#">item1</a></li>
</ul>

CSS

ul {
height: 40px;
display:inline-flex;
flex-direction: column;
flex-wrap: wrap;
border: 2px solid black;
background-color: grey;
    padding: 0;
}
li {
    list-style: none;
}
a {
    display: inline-block;
    width: 60px;
}