This combination of a grey vertical striped short sleeve shirt and navy jeans is proof that a safe off-duty outfit doesn't have to be boring. You can go down the classic route when it comes to shoes by rocking dark brown leather casual boots. Crafting a neat combination can be challenging on its own. Add cold temperatures into the equation, and the whole thing becomes all the more difficult. No worries, this here is your wintry inspo. All in all, a good example of smart casual fashion for gentlemen in their thirties.