Implements a strict single-hue UI: HSL tints/shades, tinted mono900 shadows, texture and weight instead of a second hue, including error and success states. Use when the user wants monochromatic, one-color palette, or tint/shade discipline on web or mobile. Not for duotone or multi-hue brand systems, glassmorphism as the look, or treating this as a WCAG auditor.
