Content and sidebar background colors are swapped for libadwaita apps in dark mode

[ztefn]

See screenshots below of my own app Haguichi using Adw.OverlaySplitView in vanilla Adwaita and the Mint Y patched theme. In dark mode the content and sidebar colors are swapped in Mint Y. The content pane (here on the left) should be darker than the sidebar (here on the right) to provide the most contrast.

In light mode the colors actually do correctly follow the same style as Adwaita.

Adwaita (dark)
Mint Y (dark)

Adwaita (light)
Mint Y (light)

[hthienloc]

@ztefn Thanks for the report!

I’ve adjusted the dark‑mode colours so that the content pane is darker than the sidebar and pushed a fix; the PR #536 will be merged as soon as possible.