JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
  <div class="item"></div>
  <div class="item"></div>
  <div class="item"></div>
  <div class="item"></div>
  <div class="item"></div>
</div>

CSS

.container {
  display: flex;
  flex-wrap: wrap;
}

.item {
  background-color: red;
  border: 1px solid black;
  flex: 1;
  flex-basis: 150px;
}

.item:after {
  content: "";
  display: block;
  padding-bottom: 75%;
}