Colorize the black-and-white line art with clean, vibrant, and well-balanced colors. Apply natural shading and soft highlights to create depth while preserving the manga style. Use smooth gradients, harmonious color palettes, and consistent light direction. Avoid altering the character's anatomy, face, pose, or proportions. Do not add extra elements that are not in the line art. Produce a polished, high-quality, professional manga coloring result.