About neutral-900
#171717 is neutral-900, a tailwind v4. This page shows its rgb(23, 23, 23) / hsl(300, 0%, 9.02%) / oklch(0.2046 0 0) values, WCAG contrast against black and white, an OKLCH tint-and-shade ramp, and complementary, analogous, and triadic harmonies — all computed in perceptually-uniform OKLCH.