I would say a flesh color; that’s what’s safest. If you feel daring, then a red or black.
Illusionism is an approach that offers to explain a phenomenon as an illusion of thinking and perception, and not as a real phenomenon or a phenomenon that really has the properties that it seems to some people. In this sense, illusionism is opposed to "realism" in relation to the phenomenon.
Hypermedia gives you limited control