styles.js

const styles = ({ props, state, context }) => ({
  display: 'block',
  border: '1px solid',
  
  heading: ({ props, state }) => ({
    fontWeight: props.strong && 'bold',
    color: state.isHovered ? 'blue' : 'red'
  }),
  
  content: {
    padding: '1em'
  }
});