Expand/Collapse on hover?

I want to make a skin that fits in the top of the screen, on the window border.
Normally, it looks like this:

But when the mouse is over, it's going to expand to show several controls. When the mouse leaves the skin, I want it to collapse down again.
Is it possible to trigger these animations based on whether the mouse is over or not?
Thanks
Normally, it looks like this:

But when the mouse is over, it's going to expand to show several controls. When the mouse leaves the skin, I want it to collapse down again.
Is it possible to trigger these animations based on whether the mouse is over or not?
Thanks
