Field Group and CSS

Hello,

I want to use horizontal tabs do display fields of my node type.

I found the field Group module which work perfect.

But the output of tabs is not nice, and i am not an CSS expert.

I found the very nice output with Quicktabs module (for example 'Zen').

Anybody could give me a way how i can implement the quicktabs' Zen on Field_Group ? i don't understand how to implement in the "Extra css classes" field. Should i make a copy/past from the css of Quicktabs ?

Any help woukd be very welcome

NicoPepe