Ask HN: a question about seasonal topbar colors

The topbar on this site has in the past changed either seasonally or in response to various things - I think green/red for Christmas, a black line after Aaron Swartz died, and maybe on a few other occasions for other things. Do I remember it once being green on St Patrick's day? One time I'm sure it was pink but I don't know why.

"topcolor" unlocked in my profile a few weeks ago and I played around with it a tonne before setting it back to ff6600 today. Does ff6600 mean I'll be able to see when it's changed by the admins to mark events? Perhaps the topbar color in those cases changes to overwrite everyone's anyway for the (usually very short) times they are in effect.

I'm rather curious, does anyone know?