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.