Parses hex (#rgb, #rrggbb, #rrggbbaa), rgb()/rgba(), hsl(), hsv(), hwb(), oklch(), oklab(), lab(), device-cmyk() and the 148 CSS colour names, then converts each colour to every other model with in-house maths (OKLab/OKLCH per Björn Ottosson, CIELAB D65). Also reports the exact or nearest CSS name and WCAG contrast on white and black. The preview shows sandboxed swatches over a checkerboard so alpha is visible. Everything runs locally.