When showing/hiding the player controls, the transition has five parts:
1. Controls fade in
2. Controls slide up
3. Spacing between controls expands
4. The background gradient end point (fully transparent) slides up
5. The background gradient fades in separately from the controls
The player uses quite a few gradient masks to ease the bounds of views. The top and bottom of the transcript scroll view both are gradient masked. Same as the episode title scrolling marquee and the chapter list (if the episode supports it). These are special gradients, too...