JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
<div class="wrapper__body">

<div class="box1">

</div>
<div class="box2">

</div>
</div>
</div>

CSS

.wrapper {
  display: flex;
  flex-wrap: wrap;
  overflow: hidden;
}

.wrapper__body {
  flex: 1;
  margin: 0 -30px;
  display: inherit;
  flex-wrap: inherit;
}

[class*="box"] {
  margin: 0 30px;
}

.box1 {
  flex: 1 1 400px;
  height: 100px;
  background: blue;
}

.box2 {
  flex: 1 1 200px;
  height: 100px;
  background: yellow;
}