Illustrate a character in the style of Mary Blair. The character is a 6-year-old boy with brown hair, a round face with a cute expression, a slender body, and is wearing a yellow T-shirt and shorts. Emphasize vibrant colors, whimsical design, and a playful atmosphere. Capture the innocence and joy of childhood. Capture the essence of Mary Blair's style with vibrant colors and whimsical details, with the character looking forward against a white background, in a cute watercolor illustration set against a backdrop of pure white.