Use when the user asks whether a color combination is readable or accessible, passes WCAG AA or AAA, or has enough contrast (text on a background, button, badge, link color), or what a color is in another format. Returns the exact contrast ratio, pass or fail for normal text, large text and UI components at AA and AAA, the APCA lightness contrast and a plain note. Colors can be hex, rgb(), hsl() or CSS names. Example: {"foreground": "#777777", "background": "#ffffff"}. Also returns each color in hex, rgb, hsl and oklch with its nearest CSS name.