JSFiddle - React, Tailwind, and code Playground

HTML

<section></section>

CSS

section {
    width: 300px;
    height: 300px;
    background-image:
		linear-gradient(#000000 2px, transparent 1px),
		linear-gradient(90deg, #1a1a1a 1px, transparent 1px),
		linear-gradient(#1a1a1a 2px, transparent 2px),
		linear-gradient(90deg, #000000 1px, transparent 1px);
	background-size:
		3px 3px,
		3px 3px,
		1px 1px,
		1px 1px;
}