It has been three years and I find myself asking this question again.
I would love to be able to make the locked media item shadow overlay, and the muted track overlay a lighter shade and perhaps a unique tint.
Has anything like this become available for Theme tweaking?
If I could make the adjustments, I would use a very light gray shadow over the muted track, and I would not shade the locked media items at all. I would prefer to lock the items and simply refer to the lock symbol to confirm that the items are locked.
Thank you!