[Feature] Dark mode in private windows, or a matching blue color

[yokoffing]

Is your feature request related to a problem? Please describe.

Even after resetting browser.theme.dark-private-windows, the new tab page for Private Windows is white.

Describe the solution you'd like

Either: 1) Direct users in the README what line to delete in the userChrome files so that private mode is dark, or provide a custom fix. 2) Make the page color match the navy / dark blue private browser theme you provide, by default.

Describe alternatives you've considered

Additional context

[rafaelmardojai]

I don't think you can reset browser.theme.dark-private-windows since it's set in the user.js file and will be loaded again every time you restart Firefox.

I can add documentation in the README about removing that pref from user.js. But the behavior of respecting the system color scheme in private windows is what GNOME Web does, so we'll keep that pref set to false in the theme.

[yokoffing]

I don't think you can reset browser.theme.dark-private-windows since it's set in the user.js file and will be loaded again every time you restart Firefox.

I remove the pref from the user.js and reset in about:config, then restart. But it doesn't look great. Alternatively, I think a blue page theme to match the address bar etc. would look nice. In other words, if we're using a custom theme for the private window, continue it into the page.

I'm not trying to nit-pick. But if we're not using a purple theme or dark theme, then we should extend the blue theme onto the page, instead of the glaring white.

I hope that makes sense. Thanks for the great project!