outline/app/scenes/Error404.js

// @flow
import * as React from "react";
import CenteredContent from "components/CenteredContent";
import PageTitle from "components/PageTitle";
import Empty from "components/Empty";

const Error404 = () => {
  return (
    <CenteredContent>
      <PageTitle title="Not Found" />
      <h1>Not found</h1>
      <Empty>
        We were unable to find the page you’re looking for. Go to the&nbsp;
        <a href="/">homepage</a>?
      </Empty>
    </CenteredContent>
  );
};

export default Error404;