message: add size prop
diff: @@ -4,6 +4,13 @@ import styled from 'react-emotion'
  import {withSystemProps} from './system-props'
  import theme, {colors} from './theme'
  +const sizeMap = {
  + small: `padding 0.125em ${theme.space[2]}px; font-size: ${theme.fontSizes[0]}px;`,
  + medium: `padding: 3px ${theme.space[1]}px; font-size: ${theme.fontSizes[0]}px;`,
  + large: `padding: 4px ${theme.space[2]}px; ${theme.fontSizes[1]}px;`,
  + xl: `padding: ${theme.space[1]}px; ${theme.space[2]}px; ${theme.fontSizes[2]}px;`
  +}
  +
  const outlineStyles = `
  margin-top: -1px; // offsets the 1px border
  margin-bottom: -1px; // offsets the 1px border
  @@ -16,8 +23,6 @@ const outlineStyles = `
  const styledLabel = styled('span')`
  display: inline-block;
  - padding: 3px ${theme.space[1]}px;
  - font-size: ${theme.fontSizes[0]}px;
  font-weight: 600;
  line-height: ${theme.lineHeights.condensedUltra};
  color: ${colors.white};
  @@ -26,12 +31,15 @@ const styledLabel = styled('span')`
  &:hover {
  text-decoration: none;
  }
  - ${color} ${props => (props.outline ? outlineStyles : '')}; // must be last to override other values
  + ${color}
  + ${props => (props.outline ? outlineStyles : '')}; // must be last to override other values
  + ${props => sizeMap[props.size]}
  `
  styledLabel.defaultProps = {
  theme,
  - bg: 'gray.5'
  + bg: 'gray.5',
  + size: 'medium'
  }
  styledLabel.propTypes = {
  