ibooks shelf changing colors?

Over the last few days I have had the shelf in ibooks changing colors. It has been white through ios7 and at first into ios 8 but a few days ago it turned dark gray. I tried to find if there was a way to change it but couldn't find anything. Then after a few days it turned back to white. Now It's light gray, is it supposed to change for some reason?

Hmm, I just shut of ibooks and opened it again. It opened to dark gray, stayed like that for a while and then went to light gray. Did it again and it's kind of medium gray. Weird. Then again so is the ringing of numbers on my blocked list, I hope tomorrow's is less buggy.

 

Thanks, but Again just now it went to very dark gray for a while and then light gray. It was also dark in the day for a few days, all day long. Very dark.

 

Not at all, I'll see what happens today after the update.