CSS with @layer is not well compressed

[hajimehoshi]

Thank you for the nice library! I found a minor issue:

Compressing this CSS

@layer foo {
    p {
        font-weight: bold;
    }
}

results in

@layer foo{p {
        font-weight: bold;
    }
}

[tdewolff]

Thanks for raising this issue. It is a known error that depends on an upgrade for the CSS parser to support the newer CSS syntax features. It is the next thing on the list, but due to limited time I can't guarantee a quick fix unfortunately. I'll keep you updated.