Let me join the chorus of people not wanting to dissuade you, but… concerning specifically the aspects of styling and multimedia and general-purpose extensibility, I’d like to point out Juhana Leinonen’s Vorple, which lets you use CSS and Javascript from within Inform.
Here’s a thread with a cool demo by @mulehollandaise (Hugo Labrande).
Vorple is also cross-platform, in the sense of being accessible via web browsers from various platforms. As far as I know, you normally need to run it from a server, so you could put it up on itch.io, like Hugo did, for example.
If you’d like to package it as a desktop application, you could check out this project by @Natrium729, which bundles Electron and Vorple.