This text states that "for white, L = 100, C = 0 for HCL", but the code right below demonstrates that C = NaN for white. Which then leads to the fix suggested down below, where you manually create a version of white where C = 0. Perhaps C should be 0 for white?

C is NaN. I’ve already corrected the text. Please reload?

Thank you again! Please ignore my github reply.