Design a complete color palette system in a {{tone}} tone for a {{brand_type}} targeting {{target_audience}} with a {{visual_style}} visual direction. The palette must meet WCAG AA contrast, follow monochromatic principles, and include up to 12 colors. Output: Primary Palette (2-3 colors), Secondary Palette (2-3), Accent Palette (1-2), Neutral Palette (3-4), and Semantic Palette (2-3 for success/warning/error). Each color needs hex code, usage description, and accessibility note. Maximum 600 words.