JSFiddle - React, Tailwind, and code Playground

by Artem

HTML

<div class="grid">
  <div class="box first">1</div>
  <div class="subgrid">
    <div class="subgrid">
      <div class="box">2</div>
      <div class="box">3</div>
    </div>
    <div class="subgrid">
      <div class="box last">4</div>
      <div class="box last">5</div>
    </div>

  </div>

</div>

CSS

* {
  box-sizing: border-box;
}

.box {
  border: 2px solid #fff;
  background-color: #333;
  padding: 20px;
  color: #fff;
  text-align: center;
  font-size: 20px;
  line-height: 30px;
  font-family: sans-serif;
}

.first {
  flex: 3;
}

.grid {
  display: flex;
  flex-wrap: wrap;
  max-width: 960px;
  margin: 0 auto;
  border: 1px solid #000;
}

.subgrid {
  display: flex;
  flex-direction: column;
  flex-wrap: wrap;
  flex: 9;
  border: 1px solid #f00;
  /* height: 300px; */
}

.subgrid > .subgrid {
  flex-direction: row;
  flex-basis: 33%;
  border: 1px solid #f0f;
}

.subgrid > .subgrid:last-child {
  flex-direction: column;
}

.subgrid > .subgrid .box {
  flex-basis: 50%;
}

.last {
  flex-basis: 66%;
}