IF SHADOW HANTERS WHEHE WHITE FOR FUNERALS WHAT COLOR DO THEY WEAR FOR A WEDDINGS?

I think that the guys still wear black and the girls white, because why would that change?
although, it might be switched around cause supposedly marriage is a mans worst nightmare... ;P

They wear gold. When I met Cassie Clare I asked her and she told me.

It's gold. This is mentioned in the little rhyme Sebastian/Jonathan tells Clary in City of ロスト Souls.