Incorrect s-page web component padding when scaffolding a new app with shopify-cli

I’m in the process of building a new app, and have followed the instructions in the scaffold app docs to build a new app via shopify-cli, using the new Polaris web components. According to the docs, the s-page component should render the correct padding for the page out of the box, as shown in this image for the docs:

However, in my newly built app, the padding at the top of the page is incorrect - notice that it’s much smaller:

I have no console errors. I can provide the full code but it’s literally just the template page that Shopify generates:

  return (
    <s-page heading="React Router app template">
      <s-section heading="Congrats on creating a new Shopify app 🎉">
...

Has anyone else noticied this? I’m testing it with Firefox.