message: use our own components for Header & SideNav
diff: @@ -3,6 +3,7 @@ import App, {Container} from 'next/app'
  import {Layout} from 'mdx-docs'
  import Octicon, {iconsByName} from '@githubprimer/octicons-react'
  import * as primerComponents from '../src'
  +import {FlexContainer} from '../src'
  import * as docComponents from './doc-components'
  import SideNav from './doc-components/SideNav'
  import Header from './doc-components/Header'
  @@ -30,16 +31,12 @@ export default class MyApp extends App {
  const {Component, page} = this.props
  return (
  <Container>
  - <Layout
  - components={components}
  - {...this.props}
  - routes={[]}
  - theme={customTheme}
  - header={<Header />}
  - sidebar={<SideNav />}
  - layoutMain
  - >
  + <Layout components={components} routes={[]} theme={customTheme}>
  + <Header/>
  + <FlexContainer>
  + <SideNav/>
  <Component {...page} />
  + </FlexContainer>
  </Layout>
  </Container>
  )
  