message: match header to primer.style
diff: import React from 'react'
  import Octicon, {MarkGithub} from '@githubprimer/octicons-react'
  import NextLink from 'next/link'
  -import {Text, FlexContainer, Link, Sticky} from '../../src'
  +import {Text, FlexContainer, Link, Box, Sticky} from '../../src'
  const Header = () => (
  <Sticky zIndex={100}>
  - <FlexContainer p={3} alignItems="center" justifyContent="space-between" bg="black" color="white">
  + <Box py={3} bg="black" color="white">
  + <FlexContainer className="p-responsive" alignItems="center" justifyContent="space-between">
  <NextLink href="/components">
  - <Link className="text-white" nounderline href="/components">
  - <FlexContainer ml={4} alignItems="center" justifyContent="center">
  + <Link ml={3} className="text-white" nounderline href="/components">
  + <FlexContainer alignItems="center" justifyContent="center">
  <Octicon icon={MarkGithub} size="medium" />
  <Text ml={3}>Primer Components</Text>
  </FlexContainer>
  @@ -27,6 +28,7 @@ const Header = () => (
  </NextLink>
  </div>
  </FlexContainer>
  + </Box>
  </Sticky>
  )
  