PSA: Theming changes on Nightly (for Firefox 100)

[Emilio Cobos Álvarez]

(Cross-posted to dev-platform, reply on firefox-dev@ please)

Since someone has already filed a bug about their dark colorway not changing Bugzilla to dark color-scheme anymore, I may as well post a quick PSA. After the landing of bug 1736218 and bug 1750932 there are some color scheme changes related to themes that are expected:

• The obvious one is that you can change the web content appearance by hand in about:preferences (before that, this was hidden in about:config).

• The second one is that AMO themes can override the heuristics that Firefox uses to decide whether they're dark or light, both for the theme itself (so affecting menus, tooltips, etc) and for web content. This should allow theme authors to fix a common case of "menus being dark even though the theme is light" when using images and white text, like bug 1736218.

• Colorways and most AMO themes (unless they explicitly specify their color-scheme as per above) won't change prefers-color-scheme for websites anymore, and they'll follow the OS color-scheme by default. I'm personally not a fan of this decision, and think it's nice that when you choose a "dark" colorway like "Lush bold" content becomes dark by default, but UX folks disagreed with me and I don't mind that strongly as long as users can change it.

Thanks to everyone that helped to get this done btw, including our UX team and Dao / Gijs / Rob and all others that reviewed.

Cheers,

  -- Emilio