The minimum contrast ratio between the text color and its background color should be above 4.5:1. Use any color contrast tool for adjusting the colors, until their contrast ratio is compliant.
Engine scans through the text and compares the foreground and background color for a contrast ratio of at least 4.5:1 .
The content using the minimum contrast ratio can be read by people with moderately low vision or people who do not see the full range of color.