So I've recently really got into wearing waistcoats. I'm a dude in his 20's and I think it's a very nice piece of classsy elegance. Anyway, are there any rules for wearing it casually? By casual I mean not in a suit composition. Like, with a shirt underneath it (obviously, ppl wearing waistcoats over t shirts frighten me tbh) and either a pair of jeans or a pair of semi-casual pants, like chinos or whatever and without a jacket. I guess that in this case there should be no problem if the pants and the waistcoat dont have matching colors as long as the colors work well together.