Text Decoration Thickness

Adjust how big the “decoration” is.

I think the best one should be the default, but for legacy reasons it's not. It's …

font-weight: 900

text-decoration-thickness: from-font

font-weight: 100

text-decoration-thickness: from-font

font-weight: 400

text-decoration-thickness: from-font

If the font file includes information about a preferred thickness, use that value. If the font file doesn't include this information, behave as if auto was set, with the browser choosing an appropriate thickness.