About cyan-600
#0091B3 is cyan-600, a tailwind v4. This page shows its rgb(0, 145, 179) / hsl(191.4, 99.82%, 35.13%) / oklch(0.6088 0.1126 222.14) 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.