Go to the bottom of the screen and you'll see a place where you can change the color/theme of psych central. The normal theme will just say Psych Central; I suspect you may have changed it to Tulip. There are other options and you must have inadvertently changed it. (But I was just messing with it and it does seem to be acting oddly, so perhaps something is going on. Doesn't seem to be changing consistently or holding the changes.) You might have to go to your profile and change it there under options/Forum skin to get it to save the change correctly. (ETA: Yup, that seemed to work better for me.)