JSFiddle - React, Tailwind, and code Playground

JavaScript

function test() {
    var SR = window.ShadowRoot || window.WebKitShadowRoot;
    var d = document;

    var widget = d.createElement('div');
    d.body.appendChild(widget);
    var s = new SR(widget);
    var thumb = d.createElement('span');
    thumb.innerHTML = 'Some text';
    thumb.webkitPseudo = 'x-thumb';
    s.appendChild(thumb);

    var style = d.createElement('style');
    style.innerHTML = 'div::x-thumb {' +
        'color:red;' +
        '}';
    d.body.appendChild(style);
}

test();