When navigating through local documentation in Firefox, theme setting is not preserved

[lkintact]

1. Open <Python_installation_folder>/Doc/html/index.html in Firefox. Notice that the Light theme is active.
2. Change the Theme setting at the top-right from Auto to Dark. The page turns dark, as expected.
3. Click on any link, for example What's new in Python 3.14?. Firefox opens <Python_installation_folder>/Doc/html/whatsnew/3.14.html. Notice that instead of the Dark one, Light theme is active again.

FWIW, I don't observe the issue in Chrome.

OS: Windows 10 Home 22H2,
Firefox: 145.0 (64-bit),
Python: 3.14.0.

[hugovk]

I can reproduce on macOS (with Firefox 144 and Chrome 142), although I have dark theme as my OS setting, and it resets to dark after changing to light. But it's essentially the same.

However, unless there's trivial fix, I don't think this is worth fixing, as the HTML docs are primarily intended to be viewed on a server. And it works as expected using python -m http.server for both Firefox and Chrome.