One small note: the post seems slightly confused about the use of OpenType features, as it calls for:
font-feature-settings: "colr", "calt";
but there's no 'colr' feature tag in the font's OpenType layout tables, so that's meaningless here.
I suppose this was intended to "activate" the color glyph table (COLR) in the font; but that isn't an OpenType layout feature that would be controlled by font-feature-settings, and doesn't need to be "turned on" like this.
(In addition, the 'calt' feature is (according to the spec[1]) supposed to be active by default, so it shouldn't be necessary to explicitly set it either. And indeed, the font works for me in both Firefox and Chrome without this rule; sadly Safari doesn't seem to handle it.)
Interestingly it also seems to work fine on 16.5. Browserstack doesn't have 17.1, perhaps it was broken temporarily? Unless there's some other difference with the version of Browserstack somehow..
One small note: the post seems slightly confused about the use of OpenType features, as it calls for:
but there's no 'colr' feature tag in the font's OpenType layout tables, so that's meaningless here.I suppose this was intended to "activate" the color glyph table (COLR) in the font; but that isn't an OpenType layout feature that would be controlled by font-feature-settings, and doesn't need to be "turned on" like this.
(In addition, the 'calt' feature is (according to the spec[1]) supposed to be active by default, so it shouldn't be necessary to explicitly set it either. And indeed, the font works for me in both Firefox and Chrome without this rule; sadly Safari doesn't seem to handle it.)
[1] https://learn.microsoft.com/en-gb/typography/opentype/spec/f...