Can't figure out why draft-js is not shown
<p>I followed <a href="https://facebook.github.io/draft-js/docs/overview.html#content" rel="noreferrer">draft-js document</a> to create a very simple demo of draft-js.</p>

<p>Everything seems work well, but when I open the url in Chrome, I can only see a white blank page (there is a hidden editor component there but is not visible)</p>

<p>There is no error on the console of the browser.</p>

<p>The demo project is here: <a href="https://github.com/js-demos/react-draft-js-demo" rel="noreferrer">https://github.com/js-demos/react-draft-js-demo</a>, you can clone it and follow the readme to run it.</p>

<p>I have reviewed the code very carefully, but can't figure out why.</p>