message: Update SideNav component
diff: /** @jsx jsx */
  -import { jsx } from '@emotion/core';
  -import React from 'react';
  +import { jsx, css } from '@emotion/core';
  import styled from '@emotion/styled';
  -import { css } from 'emotion';
  import PropTypes from 'prop-types';
  import {
  Drawer,
  @@ -89,7 +87,13 @@ const SideNav = props => {
  anchor="left"
  CardProps={{ className: drawerContentStyles }}
  >
  - <div css="flex-shrink: 0">{header}</div>
  + <div
  + css={css`
  + flex-shrink: 0;
  + `}
  + >
  + {header}
  + </div>
  <NavList gutter={mode === MODE.FULL ? List.KILO : List.BYTE}>
  {children}
  </NavList>
  