By Prerna Bedi (Reuters) -British fashion retailer Superdry does not expect market conditions to improve in the near term after a tough Christmas season, it said on Friday, adding that finance chief Shaun Wills will step down at the end of March. Superdry, known for its jackets and clothing inspired by American vintage styles and Japanese graphics, reported a 13.7% drop in group sales for the 12 weeks to Jan. 20 due to milder autumn weather. “A challenging consumer retail market, set against a backdrop of macro-economic uncertainty and some remarkably unseasonal weather conditions have all com…