Notification tray improvements
There is a lack of animation on the rest of the notifications after one is dismissed. Right now there is no transition and it's just an immediate change to the UI (this looks like no change if the notifications are identical in content). An animation that slides up the rest of the notifications into the space that the one that was just dismissed from would be nice here.
The "No Notifications" placeholder just pops into existence when the last notification is dismissed. A quick fade in effect or something would be nice there to not make it feel so sudden.
This is more a visual nitpick than anything, but there is a hard edge on the notification as it's being dismissed overlaying a gradient/shadow on the notification as it's being swiped away would be nice visual improvement here.