It is COMPLETELY allowed, it is a material with dark blue, and if you look for it, you can see it, transparancy is 100%!

EDIT: Color used was this

It is COMPLETELY allowed, it is a material with dark blue, and if you look for it, you can see it, transparancy is 100%! EDIT: Color used was this https://steamuserimages-a.akamaihd.net/ugc/919166841050101422/16ADD2EC458C7E834D92570AFBC1E12A78025D96/