JSFiddle - React, Tailwind, and code Playground

by minhbkpro

HTML

<div id="parent">
    <div id="child">
    </div>
</div>

CSS

#parent{
  width: 100px;
  height: 100px;
  border: 1px solid red;
  position: relative;
}

#child{
  width: 20px;
  height: 20px;
  border: 1px solid blue;
  margin: auto;
  position: relative;
  top: 50%;
  margin-top: -11px; /* height / 2 + border-width */
}