```js
// Page.stories.js

import { html } from 'lit';

export default {
  title: 'Page',
  component: 'demo-page',
};

/*
 *👇 Render functions are a framework specific feature to allow you control on how the component renders.
 * See https://storybook.js.org/docs/7.0/web-components/api/csf
 * to learn how to use render functions.
 */
export const CustomFooter = {
  render: (args) => html`
    <demo-page>
      <footer>${args.footer}</footer>
    </demo-page>
  `,
  args: {
    footer: 'Built with Storybook',
  },
};
```