Color Contrast Checker

什么是 Color Contrast Checker？

A color contrast checker measures the visual difference between two colors usually a text color and a background color and tells you whether that difference is large enough to read comfortably. It produces a contrast ratio between 1:1 (identical colors, no contrast) and 21:1 (pure black on pure white, maximum contrast) then checks that number against the thresholds set by WCAG 2.1.