Is there a way to specify "E:not(state)" in GTK3 theme?

Currently, I have to define styles in this order due to precedence:

notebook header.top tab {
}

notebook header.top tab:checked {
}

Is there a syntax for something like this:

notebook header.top tab:not(checked) {
}

This doesn’t evaluate as I would expect. It affects all tabs.

The syntax seems to be:

notebook header.top tab:not(:checked) {
}

An excerpt from the GTK CSS Overview:

Pattern Matches
E:not(〈selector〉) any E node which does not match the simple selector 〈selector〉