JSFiddle - React, Tailwind, and code Playground

by Morpheus_God

HTML

<div class="block">2121</div>

CSS

.block{
  width: 50px;
  height: 50px;
  background-color: red;
  border: 1px solid black;
  text-align: center;
  line-height: 24px;
  position: relative;
}

.block::before{
  position: absolute;
  width: 10px;
  height: 10px;
  background-color: black;
  left: 0;
  content: '';
  top: 0;
}