The dark mode still has a white background so there's no reason to have it.

What are you talking about for dark mode on the site. There is no option to toggle the theme on the site. In the book, inside of readers like kindle on ipad, maybe.

But for the site as you mention, there is no dark mode. Is this some janky extension you use that isn't working? That's note the site's fault.

If the user's OS and/or browser is set to dark mode. The site doesn't need to have a switch; its CSS has the media queries.

Ah, the change was so subtle I didn't realize it was happening. I updated the site so it's nice regardless of theme (dark/light) on the OS.