Professional black-and-white coloring book illustration, suitable for children and teenagers ages 8–15, consistent character design based strictly on the provided character reference sheet, cute but slightly mature storybook aesthetic, expressive characters, clean bold black outlines, approximately 0.75–1.2 pt minimum line weight, smooth confident linework, large open coloring areas, moderately detailed but easy to color, simple readable composition, limited background elements, no clutter, no tiny details, no intricate patterns, no dense textures, no shading, no grayscale, no hatching, no cross-hatching, no color fills, pure white background, crisp high-resolution line art, professional printable coloring-book page, centered composition, safe margins, portrait 8.5 x 11 inch composition, no frame, no border, no watermark, no unnecessary text. > Professional black-and-white coloring book page using the exact same rabbit character design from the reference sheet. The rabbit approaches the front door and bends down slightly to pick up an envelope lying on the floor. The rabbit looks curious and surprised. The entrance area is simple and uncluttered, with the door, a small doormat, and the envelope as the main environmental elements. The envelope should be clearly visible and large enough to recognize. Strong storytelling composition with the rabbit as the focal point. Clean bold outlines, smooth line art, large open coloring areas, moderately detailed, no tiny details, no clutter, no shading, no grayscale, no hatching, no cross-hatching, pure white background, professional printable coloring page, portrait 8.5 x 11 inches.