<div class="box">
  <div class="item">1</div>
  <div class="item">2</div>
  <div class="item">3</div>
  <div class="item">4</div>
  <div class="item">5</div>
  <div class="item">6</div>
  <div class="item">7</div>
  <div class="item">8</div>
  <div class="item">9</div>
</div>
body {
  font-family: monospace;
  font-size: 15px;
  line-height: 15vh;
  text-align: center;
}

.box {
  display: grid;
  grid-template-columns: auto auto auto;
  grid-template-rows: 40vh;
  grid-auto-rows: 20vh;
  grid-gap: 10px;
}

.item {
  background-color: tomato;
  color: white;
  font-size: 4vw;
  padding: 10px;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.