@applitools/css-tree/lib/syntax/atrule/nest.js

A temporary custom copy of https://github.com/csstree/csstree

export default {
    parse: {
        prelude() {
            return this.createSingleNodeList(
                this.SelectorList()
            );
        },
        block() {
            return this.Block(true);
        }
    }
};