message: Remove theme from _app.js
diff: @@ -4,7 +4,6 @@ import {Layout} from 'mdx-docs'
  import Octicon, {iconsByName} from '@githubprimer/octicons-react'
  import * as primerComponents from '..'
  import * as docComponents from './doc-components'
  -import { ThemeProvider } from 'emotion-theming'
  const {BaseStyles, Box, FlexContainer, Link, theme} = primerComponents
  @@ -43,7 +42,6 @@ export default class MyApp extends App {
  const isIndex = pathname === '/' || pathname === '/components'
  return (
  - <ThemeProvider theme={theme}>
  <BaseStyles>
  <Container>
  <Layout components={components} routes={[]} theme={customTheme}>
  @@ -60,7 +58,6 @@ export default class MyApp extends App {
  </Layout>
  </Container>
  </BaseStyles>
  - </ThemeProvider>
  )
  }
  }
  