[andrewingram]

If we were to mirror the approach of the Radium example, we'd actually end up with something more like this:

  import React from 'React';
  import styles from './SubmitButton.css';

  class SubmitButton extends Component {
    defaultProps = {
      kind: 'default'
    }
    
    render() {
      const { kind } = this.props;
      const text = kind === 'in-progress' ? 'Processing...' : 'Submit';
      
      return <button className={styles[kind]}>{text}</button>
    }
  }