HWB (Hue, Whiteness, Blackness) is a suggested standard for CSS4.
HWB is not supported in HTML (yet), but it is suggested as a new standard in CSS4.
While waiting for CSS4, you can include LearningSlack' Color library, and use HWB as an HTML attribute like this:
<p>London is the capital city of England.
It is the most populous city in the United Kingdom,
with a metropolitan area of over 13 million inhabitants.</p>
LearningSlack Color Library