Text on — WCAG contrast ratios for every pairing in the palette.

Text on →	Black	White	Blue	Gray
Black	—Same color, no contrast	19.90AAA	3.85AA Large	4.12AA Large
White	19.90AAA	—Same color, no contrast	5.17AA	4.83AA
Blue	3.85AA Large	5.17AA	—Same color, no contrast	1.07Fail
Gray	4.12AA Large	4.83AA	1.07Fail	—Same color, no contrast