JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
  <div class="d1">1</div>
  <div class="d2">2</div>

</div>

CSS

.parent{
  display: flex;
  border: 1px solid rgba(0,0,0,.5);
  height: 300px;
  width: 300px;
  flex-flow: row wrap;
  justify-content: center;
  align-items: center;
  //align-content: center;
}
.parent div{
  width: 50px;
  height: 50px;
  background-color: blue;
  margin:1px;
  color: white;
  text-align: center;
  line-height: 50px;
}

.d2{
  flex-grow: 3;
}