JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<link rel="stylesheet" href="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>
<script src="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<div></div>

CSS

body {
  padding: 20px
}

div {
  position: relative;
  width: 300px;
  height: 200px;
  background: rgba(30, 144, 255, .6)
}

div:after {
  content: '';
  position: absolute;
  left: -7px;
  top: 7px;
  width: inherit;
  height: inherit;
  background: rgba(30, 144, 255, .6)
}