diff --git a/lib/parser.js b/lib/parser.js
index d90efab..7a0e333 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -203,7 +203,7 @@ function parseSelector(token) {
     type: 'rule',
     // fix css case: .my-class:not(.class1, .class2)
     // Also case for: .wp-block-buttons:not(.is-content-justification-space-between,.is-content-justification-right,.is-content-justification-left,.is-content-justification-center)
-    selectors: token.text.split(/(?<!:not\(.+?),/).map(trim),
+    selectors: token.text.split(/(?<!(:is|:not)\(.+?),/).filter(f => f).map(trim),
     declarations: parseDeclarations(token)
   });
 }