With a few subtle switches, <b><a href=" http://www.selfridges.com/cat/The-Kooples/" style="text-decoration: none"><font color="black">The Kooples</font></a></b>’ Sport diffusion line rejigs the smart shirt formula. Based on its tried-and-true slim-fit shape, the contemporary French brand alters this version with an inky trim to the button-down collar and metallic buttons at the matching barrel cuffs. Orderly stripes align it with traditionally formal tailoring, but those low-key tweaks assert its casual status: an easy match for your dark-wash denim.