Phoenix bundling conditional @import rules

I wanted to keep my css clean but also responsive to various orientations via media queries. I was trying to accomplish this with conditional @import statements, keeping the various screen definition specific rules in their own files. For example:

@import "./mobile.css" (orientation: portrait) and (max-width: 500px);
@import "./tablet.css" (orientation: landscape) and (max-height: 850px);

But this gives the error:

Bundling with conditional “@import” rules is not currently supported

Is this a phoenix-specific issue, an issue originating in some of the tooling phoenix has magicked up for me, or something else?

Found my answer after reading Phoenix docs and following link to esbuild issue: