Thank you!
I'll take a look at improving rendering embedded font support. And that's a neat idea to be able to download it for offline, I'll give some thought to that. Appreciate your feedback!
You should make your app a PWA [1]
PWAs are basically "installable" pages which open in their own browser window and generally can work offline
[1] https://developer.mozilla.org/en-US/docs/Web/Progressive_web...
FYI - using service workers would automatically make it work offline and possibly be easier than trying to bundle it into one HTML file.