Both "bolder" and "lighter" are not allowed for @font-face font-weight descriptor. https://www.w3.org/TR/css-fonts-3/#descdef-font-weight > Name: font-weight > Value: normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 https://drafts.csswg.org/css-fonts-4/#descdef-font-face-font-weight > For: @font-face > Value: auto | <font-weight-absolute> <font-weight-absolute>? In WebKit, CSS parser accepts "bolder" and "lighter" and font resolver computes absolute weight from "bolder" and "lighter". This doesn't match other browsers behavior and the specs. Rejecting "bolder" and "lighter" improves interoperability and spec compliance. WPT.fyi https://wpt.fyi/results/css/css-fonts/variations/at-font-face-descriptors.html Firefox's CSS parser rejects "bolder" and "lighter". https://bugzilla.mozilla.org/show_bug.cgi?id=1454596 Chrome's CSS parser accepts "bolder" and "lighter" and its font resolver doesn't use "bolder" and "lighter" (I think it's confusing). https://source.chromium.org/chromium/chromium/src/+/master:third_party/blink/renderer/core/css/font_face.cc;l=661-678;drc=b80faef62a12ac2966f19b014e845a8137718885
Created attachment 406367 [details] Patch
Comment on attachment 406367 [details] Patch Thank you for reviewing! Could someone land this please?
Committed r265677: <https://trac.webkit.org/changeset/265677> All reviewed patches have been landed. Closing bug and clearing flags on attachment 406367 [details].
<rdar://problem/67081913>