<div id="root"></div>
body {
  height: 100vh;
  margin: 0;
  display: grid;
  place-items: center;
}
.box {
  width: 300px;
  h1 {
    font-size: 20px;
    margin: 0 0 1rem 0;
  }
}
View Compiled
import React from 'https://cdn.skypack.dev/react@^16.13.1';
import ReactDOM from 'https://cdn.skypack.dev/react-dom@^16.13.1';

const App = () => {
  return(
    <div className="box">
       Whatever.
    </div>
  );
}

ReactDOM.render(<App />,
document.getElementById("root"))
View Compiled

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/bulma/0.7.4/css/bulma.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.