CSS only navigation with animated bar on hover and with support for current item class.
The next few show how you can change the shape when you hover over the navigation.
The hover effect can be triggered only when the item hovered isn't the current one.
You can also set the effect so that hovering items before the current one has a different effect to hovering the ones after.
Limitations: you need to know how many items are in the navigtion, Doesn't work well on touch devices, not tested with drop downs.