JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
  <div class="col">
    <a href="">asdf</a>
    <a href="">asdf</a>
    <a href="">asdf</a>
  </div>
  <div class="col">
    <a href="">asdf</a>
    <a href="">asdf</a>
    <a href="">asdf</a>
  </div>
</div>

CSS

#container {
  display: flex;
}

#container .col {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  background: grey;
}