JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
<div class="inside">

</div>
</div>

CSS

.container{
  width:200px;
  height:100px;
  background-color:#dc5562;
}
.inside{
  width:150px;
  height:50px;
  margin:20px;
  background-color:rgba(50,80,115, 0.4);
  opacity: 1;
}