JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
    <div class="child child--left"></div>
    <div class="spacer"></div>
    <div class="child child--right"></div>
    <div class="child child--right"></div>
</div>

CSS

.child{
  width:100px;
  height:100px;
  background-color:red;
}
.parent{
  display:flex;
}
.spacer{
  flex:auto;
}