WCAG accessibility

swatch("#ffffff").contrast("#000000");          // 21
swatch("#767676").isReadable("#ffffff");        // true (AA normal)
swatch("#767676").isReadable("#ffffff", { level: "AAA", size: "normal" });
swatch("#767676").isReadable("#ffffff", { level: "AA",  size: "large" });

Auto-fix

ensureContrast walks a foreground until it meets a target ratio, preserving hue:

swatch("#888888").ensureContrast("#ffffff", { minRatio: 4.5 });
// → a darker version of #888 that clears 4.5:1 on white.

Pick the best of N

swatch.mostReadable("#ffffff", ["#888", "#555", "#222"]);
// → swatch("#222222")

Both helpers are exposed live in §04 of the playground.