For a casual look, marry a white and black cardigan with a crew-neck t-shirt — these pieces go pretty good together. Introduce brown suede loafers to the equation for an extra touch of style. As you can see here, this combo is a really savvy option, especially for weird fall weather, when the temps are starting to drop. So if you're looking for a modern yet mature getup for a 20-something guy, you found it.