JSFiddle - React, Tailwind, and code Playground

HTML

<div class='container'>
  <div class='child'></div>
  <div class='child'></div>
  <div class='child'></div>
</div>
<div class='container'>
  <div class='child'></div>
  <div class='child'></div>
  <div class='child'></div>
</div>

CSS

*{ margin: 0; padding: 0; border: 0 none; box-sizing: border-box; }

.container{
  display: flex;
  padding: 10px;
  background-color: tomato;
}

.child{
  flex: 1 0 auto;
  background-color: lightblue;
  border: 1px dashed #000;
  height: 100px;
}