Transcript highlighting - like Linkedin Learning - demo (JavaScript)

I just finished this demo and it's working for my purposes (so far), but I'd appreciate it if anyone wanted to check it out and see how it does for you. Please, let me know if you have any questions or if you see any gotchas that I've missed.

There are notes on the master slide. I've tested with the Modern player.
Important: this works with the CC text on your audio and the text in the Notes panel--they have to match. (For my demo I re-labeled Notes to "Transcript.")

You'll also see a Next button flasher that's pretty handy. (the code is in the first Execute JS trigger but it's invoked by the second one.)

You'll also (also) see I've created a "Course is Paused" graphic that show/hides with the play/pause button - I just realized that has a potential bug if the user pauses but something else is clickable on the screen, the paused graphic will stay up. (I'll post a remedy as I figure that out.) 

The credit for how to add the custom stylesheet goes to someone else on here that I've lost the link to...but many thanks, that's what started me down the path to solving the rest of this.