Its white, with a bunch of light pastel colors, and super thin text/icons. This makes it appear very bright and offers no visual contrast for the eye to decipher content. It also adds completely unnecessary transparencies which clutter the already hard to read UI.
I liked iOS a lot before. It was a little boring IMO, but it was consistent and easy to use. I'm also a fan of flat UIs when done correctly. Unfortunately iOS 7 was done poorly. Its a lot of jarring changes and unnecessary adjustments. They could have left many of the elements and color blocks intact, just flattened them, and it would have been fine. The back buttons could have been the same shape, the same font weight, etc, just no gradient/border.
Steve Jobs would never have let this be released.