JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
  <div class="a">
    1
  </div>
  <div class="a">
    2
  </div>
  <div class="a">
    3
  </div>
  <div class="a">
    4
  </div>
  <div class="a">
    5
  </div>
  <div class="a">
    6
  </div>
</div>

CSS

.a {
  border: 1px solid black;
}

#container {
  display: grid;
  grid-auto-columns: minmax(10px, 35px);
  grid-template-rows: 1fr;
}