Part of the cachet of this waterfront phenom is that it’s three restaurants in one, with each floor catering to a different mood. Yet consistently satisfying vittles are served from the roof-deck down. The roof itself is retractable, so you can bask in the sun with sushi and a pitcher of sangria, watching planes fly into Logan across the water. More upscale is the second floor, where shrimp cocktail chills in an elegant igloo. And the first floor is comfortably casual, serving a stellar crabmeat salad and throwback odes, like the Portuguese seafood stew from the original Legal’s in Inman Square.