To chime in, I would say there should be special version of the browser to account for the hinge. Why? I know of no way (yet) to code HTML/CSS to counter or adapt this.
Microsoft is submitting HTML/CSS additions to the web standards to W3C for dual screens. In one of the videos posted yesterday for the Microsoft 365 Developer Day shows the text and images flowing around the hinge while in the book posture. That video also talked about the W3 submissions. I may have to re-watch the video. The answer to my question may be on it.