When you get swept up by Keira Knightley’s upcoming portrayal of Leo Tolstoy’s famous heroine in “Anna Karenina” — which we know you will — you can channel the tragic romantic through Banana Republic’s new, sophisticated collection. Following the success of its “Mad Men”-inspired line, the retail giant teamed up with the new film’s acclaimed costume designer, Jacqueline Durran, for a capsule reflecting the elegance and luxury of 19th-century Russia. Pieces include feminine black lace dresses, rich faux fur-trimmed coats and tailored styles for him. But we especially have our eyes on the accessories, like chic faux fur hats — which double as shrugs — and opulent necklaces. Our own romances could use a touch of drama.