Sass functions that support accessible color contrast ratios
Minimum Sass version 3.4.25. Libsass 3.5.4 (best performance).
Editable sandbox on CodePen to see how this all works. Change the color variables to see the updates in real-time within the size tests.
When an edge case has been encountered, a version in SassMeister with debug output is helpful to see what might be happening (I changed the main function to a mixin so I can debug the output):