I've since been informed since that the header floats for logged in users, but not for *logged out* users, and the prototype page is a logged out view. So I'm good there.

Coming back to offer a bit more feedback. The version of https://di-content-separation.web.app that is live right now, 3/3/2023 5:30pm EST, looks really good. The white background for the header is ok, though I kinda liked it being a darker shade. I would use this in Zebra #9 mode, with header background, with borders, and with framed menus.

I personally like the dark header, for what it's worth. It becomes a bit like a reading guide for me as I scroll down. How much "user preference" is the team open to? Could the skin have a "dark/light" header selection?

I am in the midst of a major work project so don't have much time to wax on and on....

Blue_whale is certainly an improvement. Note that Zebra #9's primary purpose is to bound the reading area though. I can only speak for the goals I have in mind (General dyslexia and neurodivergent concerns), but for someone like me, the goal *is* to de-emphasize the TOC. Bounding the article creates a box for eyes that are scanning left to right to recognize and remain on the article content, rather than slipping back to the TOC or into whitespace. That said, blue_whale's clearly delineated TOC does partially provide a left side boundary. I'd still prefer Zebra #9, but Blue_Whale would help.

In T259240#8540780, @alexhollender_WMF wrote:

In T259240#8540680, @Ferret wrote:

This really isn't the same thing as the feedback from the extensive Discord meeting, which spent some time on the Zebra prototypes.

Agreed. That is a related but somewhat separate issue. My understanding is that this task is specifically about the gray "out of bounds" area.

In T259240#8540070, @alexhollender_WMF wrote:

circling back to @VulpesVulpes825's idea of adding a slight box-shadow to the main (white) container, to make it more clear/intentional that the gray area is out of bounds:

Disappointed to see this revert. I never commented on the cu-l as it was discussed, but once the link was available I silently began using it just naturally, and immediately noticed it's disappearance. So that's my 2 cents. It helped my workflow.