Apparently Marc Jacobs hasn’t had his fill of the Seventies because his Marc by Marc Jacobs runway referenced the era yet again, just dialed down a notch. And indeed, the first girl out, Frida Gustavsson, in an adorable bucket hat, looked bound for the boardwalk in her colorful striped tank dress paired with canvas sneaker wedges. That sportif vibe continued — slouchy jumpsuits, T-shirts cut like sweaters — as did the summery Seventies portion, in the colorful parade of high-waisted midi skirts worn with tight sweaters, kicky halter dresses in polka dots and blouses tucked into retro bathing suit bottoms. Graphics, especially stripes, played a major part, adding to the collection’s overall relaxed and resort-y feel. Jacobs also threw in a smattering of last season’s military motifs as well as a few pared-down classics seemingly lifted from fall’s Marc Jacobs collection, such as the structured and stylish oatmeal-colored twill coat. Not that anyone’s complaining at these kid-sister prices.