css/docs/src/SideNav.js

import React from 'react'
import {withRouter} from 'next/router'
import {default as NextLink} from 'next/link'
import {BorderBox, Link, Flex, Relative} from '@primer/components'

const NavLink = withRouter(({href, router, ...rest}) => (
  <NextLink href={href}>
    <Link color="gray.9" href={href} m={0} mb={4} fontWeight={router.pathname === href ? 'bold' : null} {...rest} />
  </NextLink>
))

const SideNav = props => (
  <Relative is="nav">
    <BorderBox
      {...props}
      width={['100%', '100%', 256, 256]}
      height="100%"
      bg="gray.0"
      display="inline-block"
      borderTop={[1, 1, 0, 0]}
      borderRight={1}
      borderColor="gray.2"
      id="sidenav"
    >
      <BorderBox border="none" borderBottom={1} borderRadius={0} borderColor="gray.2" bg="gray.0">
        <Flex flexDirection="column" alignItems="start" p={5}>
          <NavLink href="/css/support">Support</NavLink>
          <NavLink href="/css/utilities">Utilities</NavLink>
          <NavLink href="/css/objects">Objects</NavLink>
          <NavLink href="/css/components">Components</NavLink>
        </Flex>
      </BorderBox>
    </BorderBox>
  </Relative>
)

export default withRouter(SideNav)