Change element height when sticky

Hello,

First of all, thank you for this great plugin. I only miss one feature: is there a way to make the element smaller when it′s sticky?

In my example the navigaton bar is 75px high, but this is too much when it′s sticky and I would like to reduce its height to 50px ONLY when i′m scrolling down.

Thank you for your suggestions in advance.

The page I need help with: [log in to see the link]