[tw5] Video Background

Hello All, I’ve been using Tiddlywiki for quite a while now, but I’m still a bit ignorant when it comes to how it works under the hood. I’m building a new site right now and I’ve managed to get everything the way I want it, but I would like to have a video background playing full-window in the story river, preferably with a button somewhere that allows the user to toggle playback. I’ve searched by haven’t found anything that gets me very far. Is this even possible and if so, how would I go about doing it? This is probably the best I’ve seen for the effect that I want to achieve (but the sidebar and the tiddlers would not be transparent): How To Create a Fullscreen Video Background

I’m using the excellent Notebook theme, if that helps.

Thanks in advance,
Scott