This spring, Dior Homme gives black tie a lightweight, casual feel with an informal lineup of summer tuxedos and suiting. In this new collection, Dior Homme’s artistic director, Kris Van Assche, juxtaposes the notion of tailored, formal pieces with the ease of casual, sport-driven informality. Specifically bending the rules are new silhouettes like the “shorts suit,” which serves to transport modern men from the boardroom to the beach, and a summer tuxedo, which is a one-button, athletic-style tuxedo in lightw…