For a casual outfit, team a green-yellow crew-neck sweater with blue jeans — these two pieces work beautifully together. A pair of burgundy leather work boots easily steps up the street cred of this look. In the winter season, when functionality is paramount, it can be easy to surrender to a less-than-stylish ensemble. This ensemble, however, is a clear example that you can actually stay snug and remain equally stylish in the winter season. Casual getups for stylish gents in their 30s aren't actually that hard, as you see here.