message: make flex components compose Box
diff: @@ -3,14 +3,15 @@ import PropTypes from 'prop-types'
  import {display} from 'styled-system'
  import {COMMON, FLEX_CONTAINER, FLEX_ITEM} from './constants'
  import theme from './theme'
  +import Box from './Box'
  -const Flex = styled.div`
  +const Flex = styled(Box)`
  ${FLEX_CONTAINER}
  ${COMMON}
  ${display}
  `
  -Flex.Item = styled.div`
  +Flex.Item = styled(Box)`
  ${FLEX_ITEM} ${COMMON};
  `
  