JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="flex-container wrap">
  <li class="flex-item">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
  <li class="flex-item">6</li>
  <li class="flex-item">7</li>
  <li class="flex-item">8</li>
</ul>

CSS

.flex-container {
  padding: 0;
  margin: 0;
  list-style: none;
  border: 1px solid silver;
  -ms-box-orient: horizontal;
  display: -webkit-box;
  display: -moz-box;
  display: -ms-flexbox;
  display: -moz-flex;
  display: -webkit-flex;
  display: flex;
  width: 520px;
  height: 520px;
  -webkit-flex-wrap: wrap;
  flex-wrap: wrap;
  align-content: flex-start;
}

.flex-item {
  background: gold;
  padding: 5px;
  width: 100px;
  height: 100px;
  margin: 10px;
  
  line-height: 100px;
  color: white;
  font-weight: bold;
  font-size: 2em;
  text-align: center;
}