When there are fixed elements on a horizontal-bt page, they do not move properly.
Created attachment 196065 [details] Test case
The containers are on the place in Safari 16.4.1 similar to Chrome Canary 115 and Firefox Nightly 114 but the text within are not. It is moved on bottom while Chrome Canary 115 and Firefox Nightly 114 are matching in the text position within container. Might be something to add on Radar to track and also update bug title etc.
> -webkit-writing-mode: horizontal-bt; :| not sure what to do with this.