[CSS3UI] x/y cursor hotspot values

Hi,
I got a question about the hotspot position values. They are defined to 
be a <number>, i.e. non-integer values are allowed. But, what is the 
meaning of a non-integer value? For that matter, what is the unit of the 
x/y position? I would assume (device) pixels, but the spec does not 
say... And a non-integer value for a pixel unit does not make much sense 
to me.

http://www.w3.org/TR/css3-ui/#cursor

-biesi