Letter Left Unsent Cafe Illustration Composition

Create a stylish vertical 3:4 anime fashion illustration in expressive ink and watercolor style, set at a small cafe table by a window. Show a young woman named {argument name="character name" default="Saiyu"} seated in three quarter view, wearing a wide black hat, short tousled {argument name="hair color" default="ash brown hair"}, a black off shoulder camisole dress with thin straps, a black choker, round black earrings, and glossy black nail polish. Her face is intentionally covered by one large centered opaque square censor block in a warm taupe to brown gradient, hiding most facial features while leaving part of one eye, hair, hat, ear, and shoulder visible. Her right hand reaches toward a black sealed envelope on the table; the envelope has exactly 1 round yellow lemon slice wax seal. Beside it is exactly 1 tall clear glass of dark iced drink with exactly 1 black straw, exactly 1 yellow lemon wheel garnish on the rim, and exactly 1 yellow circular emblem printed on the glass. Use a limited palette of cream, black, charcoal, muted brown, and bright lemon yellow accents. Compose the scene with a dramatic diagonal black window frame on the left foreground, blurred yellow flowers and leaves outside the window, a white tabletop with rough dry brush shadows, and sketchy black ink borders. The mood should feel like a captured decisive moment, titled conceptually {argument name="scene title" default="Letter Left Unsent"}: intimate, fashionable, bittersweet, and cinematic. Add a small subtle watermark like signature text {argument name="signature text" default="SAIYU。"} in the bottom right corner. Keep the illustration loose and painterly with visible brush texture, high contrast black shapes, soft cream background, and no extra characters or readable text beyond the signature.