JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box"></div>

CSS

* {margin: 0;padding: 0}

body {
  background-image:
    linear-gradient(to right, rgba(0,0,0, 0.15) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(0,0,0, 0.15) 1px, transparent 1px);
  background-size: 50px auto, auto 50px;
}

.box {
  margin-left:  calc(100%*2/5 - 200px*2/5);
  margin-right: calc(100%*3/5 - 200px*3/5);
  width: 200px;
  height: 150px;
  background: red;
}