The menu buttons are skewed but text angled at 20 degrees is not optimal. You can counter that with font-style: italic; if you adjust the skew correctly but that is a fragile method. What you need to do is to skew the menu links the other way.
This is fine except for the minor detail that the link is skewed back so the clickable area doesn't match the buttons completely. The upper left and lower right corners are not clickable and a small area outside the lower left and upper right corners is clickable.
The reverse skew is now moved to a dummy element inside the links. Note that in this example, every pixel on the buttons is clickable including the upper left and lower right corners. And nothing outside the buttons is clickable.