Imaginem and blacksilver theme

Hi everybody
I’m new here.
I try to write to an author, Imaginem, about Blacksilver, but I have no answer.
I’m worried about the next one because if I don’t even have an answer for a first contact, how will the next one…
Does anyone here know the blacksilver theme? I just want to know if the background with the lightbox can be white? I see on all the examples a grey background…
Many thanks
Thierry, from france