Make the site responsive

[Otterfan]

Describe the bug Some page elements (the menu, the breadcrumbs) and certain pages (narrative pages, galleries) display poorly on mobile.

Link to example

• http://localhost:1313/old-oil-paintings/gallery-page/
• http://localhost:1313/old-oil-paintings/narrative-page/

To Reproduce

1. Go to one of the bad pages.
2. Smush the window size down very tiny.
3. Look at the page.

Expected behavior All images should be 100% of the page width on mobile. Navigation should be compressed.

Screenshots