Femme élégante en robe en satin noir sur escalier en marbre

a woman seated gracefully on a wide, elegant marble staircase inside a classic, upscale interior. She's wearing a black satin slip dress with delicate lace detailing along the neckline and hem, giving a timeless, sensual, and classy evening look. Her posture is relaxed yet confident, with one leg crossed forward, highlighting the dress's flow. She's styled with black platform heeled pumps and a small black handbag.