Developer Edition theme documentation (and regressions)
bgrinstead at mozilla.com
Tue Aug 11 21:13:06 UTC 2015
I've added some technical information about the Developer Edition theme here: https://wiki.mozilla.org/DevTools/Developer_Edition_Theme. This includes basic info about how it's implemented, as well as instructions with screenshots for how to apply it in a local build: https://wiki.mozilla.org/DevTools/Developer_Edition_Theme#How_To_Apply.
If you are making changes to the default theme, can you please test them out to make sure they don't break the Dev Edition theme? Alternatively, if you suspect that something might break it but aren't able to check can you let me know in the bug so I can track it? Ideally at some point we will be able to use mozscreenshots  in automation to track visual changes which would remove this manual step.
The main sources of breakage are changes to the primary UI (location bar, tabs, find bar, nav bar toolbarbuttons). No need to worry about secondary UI (including all popups and context menus) or in-content pages, since the theme doesn’t change those.
We've tried to limit the amount of duplicated selectors / properties as much as possible by using CSS variables when available . Hopefully we can expand their usage over time, and get to a point where the theme is just a collection of variables and it could somehow become a 'normal' lightweight theme.
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