JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block"></div>

CSS

.block{
  width: 100px;
  height: 100px;
  border: 1px solid green;
  background: #fff;
  box-shadow: 0 1px 0 0px rgba(0,0,0,.5);
  border-radius: 3px;
}