Abercrombie & Fitch was “the brand of the moment” a decade and a half ago. Sales of its preppy clothes had jumped into the billions, teens had ranked it as the sixth-coolest brand and its newly launched surfer-lifestyle line, Hollister & Co., was an instant sensation. But now, with stores like H&M and Zara turning white tees into fashionable pieces, Abercrombie wants to win back its base. The retailer reported its 10th straight decline in quarterly sales on Thursday, with net sales decreasing by 6% to $891 million, according to an earnings conference call.