A single HTML file for architecture docs

I maintain a single HTML file as an architecture board for the product I'm building. Definitions, data models, API surface, routes, changelogs, postmortems. One file, opens in a browser, shows the state of things at a glance. I've been using it to stay oriented while developing Tanso, and it's been useful enough that I wanted to share it in case anyone else has been thinking along the same lines. The origin was simple: I kept asking AI tools to generate structured documents (ERDs, changelog tables, postmortem writeups) and discarding them after a single look.