Mozilla disagrees. https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Writin...

		rezistik on April 24, 2015 \| parent \| context \| favorite \| on: A modern responsive front-end framework based on M... Mozilla disagrees. https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Writi... They explicitly state using css classes is more performant than using tags. I'd be interested in a CSSPerf(Do they have those?)

As others have pointed out, that article is now 15 years old.