JSFiddle - React, Tailwind, and code Playground

HTML

<div class="grid"></div>

CSS

html,body, .grid{
    height:100%;
    width:100%;
}
.grid{
    background-image: repeating-linear-gradient(0deg,transparent,transparent 70px,#CCC 70px,#CCC 71px),repeating-linear-gradient(-90deg,transparent,transparent 70px,#CCC 70px,#CCC 71px);
    background-size: 71px 71px;
}