React not rendering on codepen

This is my project

I don’t understand why it doesn’t work on codepen, it works perfectly on my machine with npm start
Here is the project on github:

Your TextArea component is a functional component, so there’s no need for render(). Just return the JSX directly.

const TextArea = () => {
  /* State initialization code, event handlers, etc.  */

  // there should be no render() here!
  return (
    <div className="App">
      {/* ... */}
  1. Move the link to react-markdown below the links to react/react-dom

  2. Call useState on the React object React.useState()

  3. As said, remove the render method surrounding the return.