JSFiddle - React, Tailwind, and code Playground

HTML

<div class="grid">
  <div class="grid">
    <div class="cell">1</div>
    <div class="cell">2</div>
  </div>
  <div class="grid">
    <div class="cell">3</div>
    <div class="cell">4</div>
  </div>
</div>

CSS

div {
  box-sizing: border-box;
  margin: 2px;
}

.grid {
  display: flex;
  flex-flow: row wrap;
  border: 2px solid blue;
  flex: 1;
}

.cell {
  flex: 1;
  min-width: 100px;
  border: 2px solid red;
  background: white;
  height: 100px;
}