We can wear a sweatshirt (hoodie or crew) if it is all one color.  Management prefers navy blue but I have seen all colors and have not heard anything.  We are seeing all shades of blue on hourly associates.  One day I wore a lighter blue and something was said.  Others can wear any shade (even aqua) and I see it on a regular basis.  I still have to wear the lab coat (I am in photo lab).