message: export withDefaultTheme(Box)
diff: import React from 'react'
  import Block from './Block'
  +import {withDefaultTheme} from './system-props'
  const Box = props => <Block {...props} />
  @@ -10,6 +11,8 @@ Box.defaultProps = {
  borderRadius: 1
  }
  -Box.propTypes = Block.propTypes
  +Box.propTypes = {
  + ...Block.propTypes
  +}
  -export default Box
  +export default withDefaultTheme(Box)
  