JSFiddle - React, Tailwind, and code Playground

CSS

body::before { 
    content: "";
    height: 10px;
    width: 110%;
    position: fixed;
    top: -10px;
    left: -10%; 
    -webkit-box-shadow: 0 0 10px rgba(0,0,0,.65);
       -moz-box-shadow: 0 0 10px rgba(0,0,0,.65);
        -ms-box-shadow: 0 0 10px rgba(0,0,0,.65);
         -o-box-shadow: 0 0 10px rgba(0,0,0,.65);
            box-shadow: 0 0 10px rgba(0,0,0,.65);
}

body { overflow-x: hidden; }

JavaScript

// http://genelocklin.com/428-add-depth-to-your-webpage/