JSFiddle - React, Tailwind, and code Playground

HTML

<html>
    <head>
        <style src="some.css"></style>
    </head>
    <body>
        <iframe id="myFrame" ></iframe>
    </body>
</html>

CSS

#myFrame{width:400px; height:400px; border:3px solid black;}

JavaScript

$("#myFrame").contents().find("body").append('<style src="'+$("style[src='some.css']").attr('src')+'"></style><h1>Alex</h1>');