How do mobile skins work?

[femco]

Hi,
i just noticed that there are so called mobile skins available for roundcube. Iam wondering how they work. Are they replacements for normals skins such that using one of them would affect the view in the normal browser too, not just on a mobile device?
Or is there some kind of device detection so that mobile skins are only used on a mobile phone? Or is there an extra plugin necessary? Or do i have to install roundcube twice using different virtual hosts like:
domain.com/webmail
and
domain.com/mobilemail

and setup different skins for each installation?

[krelvinaz]

Best response would most likely be to ask the skin designer.