[Feature]: Allow importing `unfonts.css` in the CSS

[benface]

Demo URL

No response

Describe the feature

For custom fonts, we have to import 'unfonts.css' in JS, but that creates an extra CSS file / <style> tag; it would be nice to be able to import it directly in our existing CSS (with e.g. @import 'unfonts.css' – I tried that and it doesn't seem to work).