A simple yet cute watercolor painting of a charming small castle perched on top of a hill, surrounded by a vibrant rainbow arching over the castle. In the foreground, 2 joyful children dressed as princ and princess are running towards the castle, their faces filled with excitement and wonder. The scene is bathed in warm, soft sunlight, with delicate pastel colors dominating the palette: light blue, light pink, light green and white. The style is reminiscent of Mary Blair, with whimsical and dreamlike elements, detailed yet stylized characters, and a fairytale-like atmosphere. The image should evoke a sense of magic, wonder, and innocence, with a soft, painterly technique: cartoon children's book illustration, in style of Mary Blair, hand-drawn details, soft edges, and subtle gradients --ar 2:3