I just dropped my phone while playing with it and trying to get sand out of the camera lens cover...
Now my theme seems to have changed, my icons are still the right colour, but the black transparent box behind them has now become super transparent, i can see little squares around the icons, there's also a a black edge on the top of the panel and edge creeping in the bottom right and left corners.
Did i press something in the fumble to catch it on the way down?! I would take a picture, but i only have the camera on my phone so it's difficult!