How do you change theme/skin?

Hi, Can anyone advise me how you change the theme or skin or if this is possible at all? I can change only the colour from what i can see. Thanks

Hi,
unfortunately advanced changing of the theme or skin is not possible at the current and next version (we changed the theme and skin of version 3.0 a lot and it is very nice, I think). We will consider it to our future versions.

Regards