content: import React from 'react';
  import ReactDOM from 'react-dom';
  
  import Button from './button';
  
  const App = () => (
    <div>
      <div>
        <Button>Everything is normal ....</Button>
        &nbsp;&nbsp;
        <Button error>Oh no, there is an error!</Button>
      </div>
    </div>
  );
  
  ReactDOM.render(<App />, document.getElementById('app'));
  