diff --git a/lisp/textmodes/css-mode.el b/lisp/textmodes/css-mode.el
index 204331ec72f..19f5fa303f9 100644
--- a/lisp/textmodes/css-mode.el
+++ b/lisp/textmodes/css-mode.el
@@ -1821,8 +1821,8 @@ can also be used to fill comments.
                   (property constant string)
                   (error variable function operator bracket)))
     (setq-local treesit-simple-imenu-settings
-                `( nil ,(rx bos (or "rule_set" "media_statement") eos)
-                   nil nil))
+                `(( nil ,(rx bos (or "rule_set" "media_statement") eos)
+                    nil nil)))
     (treesit-major-mode-setup)))
 
 ;;;###autoload