usage of --aspect-ratio variable without fallback

[Paulolrl]

I'm having trouble when I import the lib css, because postcss-custom-properties gives an annoying warning saying that --aspect-ratio variable is undefined and doesn't have a fallback.

Expected behavior
It would be good if the css had the aspect-ratio fallback so I could import the lib css without the warning, right now I have to copy the css to avoid the warning.

Screenshots