text: import React from 'react';
  import Card from '@material-ui/core/Card';
  import CardContent from '@material-ui/core/CardContent';
  import { Title } from 'react-admin';
  
  export default () => (
      <Card>
          <Title title="Not Found" />
          <CardContent>
              <h1>404: Page not found</h1>
          </CardContent>
      </Card>
  );