message: introduce categories of system props
diff: @@ -2,6 +2,34 @@ import styled from 'react-emotion'
  import {compose} from 'ramda'
  import * as system from 'styled-system'
  +export const COMMON = ['color', 'space']
  +
  +export const TYPOGRAPHY = COMMON.concat('fontFamily', 'fontWeight', 'lineHeight')
  +
  +export const LAYOUT = COMMON.concat(
  + 'borders',
  + 'borderColor',
  + 'borderRadius',
  + 'boxShadow',
  + 'display',
  + 'size',
  + 'width',
  + 'height',
  + 'maxWidth',
  + 'maxHeight',
  + 'minWidth',
  + 'minHeight'
  +)
  +
  +export const POSITION = [
  + 'position',
  + 'zIndex',
  + 'top',
  + 'right',
  + 'bottom',
  + 'left'
  +]
  +
  export function getSystemProps(props) {
  return props.map(prop => {
  if (typeof system[prop] === 'function') {
  