The ratio of pt to px is 1.33333 #25
Description
Hello, excellent set of resources, though on the font-sizing-and-contrast.html page, there's a minor error, a 14pt font equals 18.7px, not 19.2px.
The relationship is 11/3rd points to one px.
Points are larger than CSS reference px by 1.33333, so multiply points by 1.33333 to get equivelent px, and divide px by 1.33333 to get equivelent pt.
WCAG 2 defines 14pt (bold) and 18pt (normal) as the break points for 3:1 vs 4.5:1 for AA level. These equate to 18.7px and 24px respectively.
Additional info
Other moderns standards indicate higher contrast requirements for small text. And in fact, contrast is more associated with font weight or line thickness, rather than color per se.