JSFiddle - React, Tailwind, and code Playground

HTML

<div class=bg>
   <div class=box>
       blabla
   </div>
</div>

CSS

html,body { min-height: 100%; }
body { background: yellow; }
.bg {
    background: blue;
    padding-top: 5em;
}
.box {
    margin: 0 auto;
    width: 20em;
    height: 100em;
    background: red;
}