diff --git a/src/nwsapi.js b/src/nwsapi.js
index 7432c54..9057584 100644
--- a/src/nwsapi.js
+++ b/src/nwsapi.js
@@ -78,7 +78,7 @@
   GROUPS = {
     // pseudo-classes requiring parameters
     linguistic: '(dir|lang)(?:\\x28\\s?([-\\w]{2,})\\s?(?:\\x29|$))',
-    logicalsel: '(is|where|matches|not|has)(?:\\x28\\s?(' + '[^()]*|.*' + ')\\s?(?:\\x29|$))',
+    logicalsel: '(is|where|matches|not|has)(?:\\x28\\s?(' + '[^()]*(?:\\([^()]*(?:\\([^()]*\\)[^()]*)*\\)[^()]*)*' + ')\\s?(?:\\x29|$))',
     treestruct: '(nth(?:-last)?(?:-child|-of\\-type))(?:\\x28\\s?(even|odd|(?:[-+]?\\d*)(?:n\\s?[-+]?\\s?\\d*)?)\\s?(?:\\x29|$))',
     // pseudo-classes not requiring parameters
     locationpc: '(any\\-link|link|visited|target|defined)\\b',