Provide fallback font metrics in css

[xPaw]

See https://developer.chrome.com/blog/font-fallbacks/

I used the following in v3, but properly authored metrics for v4 would be great to have.

@font-face {
	font-family: fallback-inter;
	ascent-override: 90.20%;
	descent-override: 22.48%;
	line-gap-override: 0.00%;
	size-adjust: 107.40%;
	src: local("Arial");
}

body {
	font-family: Inter, fallback-inter;
}

[kenmcd]

properly authored metrics for v4 would be great to have.

What do you define as "properly authored metrics"?

[xPaw]

Mostly that I'm not a font specialist, so I don't know how to correctly calculate these metrics.