Traditional RGB and HSL color models suffer from severe perceptual non-uniformity: yellow and blue share identical nominal lightness values in HSL despite human photoreceptors perceiving yellow as dramatically brighter. In Björn Ottosson's OKLCH color space, perceived lightness and chroma are mathematically decoupled from polar hue angle, enabling programmatic palette shifts and algorithmic contrast ratios that stay aesthetically invariant and WCAG-compliant without manual eye-tuning. bottosson.github.io