modified

build/node_modules/css-tree/lib/syntax/pseudo/common/nth.js

@@ -0,0 +1,9 @@
+var DISALLOW_OF_CLAUSE = false;
+
+module.exports = {
+    parse: function nth() {
+        return this.createSingleNodeList(
+            this.Nth(DISALLOW_OF_CLAUSE)
+        );
+    }
+};

build/node_modules/css-tree/lib/syntax/pseudo/common/nthWithOfClause.js

@@ -0,0 +1,9 @@
+var ALLOW_OF_CLAUSE = true;
+
+module.exports = {
+    parse: function nthWithOfClause() {
+        return this.createSingleNodeList(
+            this.Nth(ALLOW_OF_CLAUSE)
+        );
+    }
+};

build/node_modules/css-tree/lib/syntax/pseudo/common/selectorList.js

@@ -0,0 +1,7 @@
+module.exports = {
+    parse: function selectorList() {
+        return this.createSingleNodeList(
+            this.SelectorList()
+        );
+    }
+};