Step to reproduce:

1. Check the background colors with light theme (in my case macOS without system Dark theme)
2. Switch TB to Dark theme

Actual results:

1. Light theme : Folders pane, Messages list headers & Quick filters have the same background color
2. Dark theme : Folders pane, Messages list headers have the same background color. Quick filters is different

This make it hard to visually understand the place and hierarchies (or flow: Folders > Quickfilter > Message list) and too patchy (dark, clear, dark, clear, ...).

Expected results:
Quick filter toolbar background should be the same color as Folders pane & Messages list columns headers background

Before Supernova UI's switch, in TB 102, the hierarchies and flow were okay

Not sure which Platform are impacted.

Screen capture
TB 112a1 : https://bugzilla.mozilla.org/attachment.cgi?id=9320160
TB 102 : https://bugzilla.mozilla.org/attachment.cgi?id=9320540

The inconsistency comes from the different styling that is applied if we're dealing with OS Dark mode or TB Dark theme, as themeing allows to override the default styling for specific areas, like the folder pane (sidebar) and quick filter mode.

I'm not a fan of these inconsistencies and we should fix them.

Proposal:

• Folder pane and Quick Filter bar: var(layout-bakground-1)
• Message list is var(layout-bakground-0)

We should also change our default Dark Theme to respect these values (the layout-background-* dark variations), so we remove the inconsistencies between those states.

Richard, what do you think?

Pushed by mkmelin@iki.fi:
https://hg.mozilla.org/comm-central/rev/dc29c1d6905f
Synchronize the theme colors with colors.css. r=aleca

Comment on attachment 9322552 [details]
Bug 1820794 - Synchronize the theme colors with colors.css. r=aleca

[Triage Comment]
Approved for beta

Thunderbird 112.0b3:
https://hg.mozilla.org/releases/comm-beta/rev/6c59f960f966