All interesting suggestions. I might add a toggle for horizontal mode, but would probably retain both modes to not lose functionality. For my other apps I have forks of each version, with the idea that if it changes radically from one version to the next, one can always go back to a live copy of the old version.

I pushed an Apache 2.0 license. Feel free to clone the GitHub repo and throw Claude at it. It might surprise you how well it can add features to a single file HTML; it can work out basically how the entire thing works without needing to read any docs. So by all means, vibe code a fork :)