While resizing, a white window background is shown

[Julesssss]

Problem

When resizing the web window in dark mode there's a very obvious white color as the window background.

Screen.Recording.2022-11-24.at.11.42.55.mov

This was pointed out here on the PR, but made a separate issue to help unblock the merge.

Solution

We should try to use our bg colour instead.

[Julesssss]

Replacing with this issue to enable the full checklist and bugzero process