I've noticed that some of the elements in the new design don't contrast enough from their surroundings.
Example: - Hyperlinks are dark red, so dark that I have difficulty distinguishing them from black, especially on an LCD screen which isn't at the perfect precise viewing angle (from an angle the colours change slightly). - The accept-answer checkmark (which is clicked to select the accepted answer) and the accepted-answer checkmark are so similar that I can barely tell them apart.
For what it's worth I noticed the link problem on other SE sites as well.