Mid-Century European Children's Book Illustration Style

Transform this image into a children's book illustration inspired by mid-20th-century European styles. Use loose, expressive black ink lines to outline the figures, as if drawn by hand. Apply a soft, retro color palette - muted greens, sky blues, warm reds, and cream - with watercolor or delicate digital brush textures. Leave some background areas uncolored to create a light, airy feeling. Simplify details, use childlike proportions, and aim for a warm, poetic, and nostalgic tone. The composition should feel playful and gentle, like a storybook scene drawn on paper.