diff --git a/content/install-user-css.js b/content/install-user-css.js
index a638f1b7..a8516782 100644
--- a/content/install-user-css.js
+++ b/content/install-user-css.js
@@ -270,9 +270,6 @@ function initUsercssInstall() {
 }
 
 function isUsercss() {
-  if (!/\.user\.(css|styl|less|scss|sass)$/i.test(location.pathname)) {
-    return false;
-  }
   if (!/text\/(css|plain)/.test(document.contentType)) {
     return false;
   }