diff --git a/layouts/partials/stylesheet.html b/layouts/partials/stylesheet.html
index 2cb47b0c5f..c49b874e74 100644
--- a/layouts/partials/stylesheet.html
+++ b/layouts/partials/stylesheet.html
@@ -36,7 +36,7 @@
         if( !s || !s.match ){
           return '';
         }
-        var matches = s.match(/^.*\/?theme-(.*?)\.css.*$/);
+        var matches = s.match(/^.*\/?theme-([^\/]*?)\.css.*$/);
         var theme = matches && matches.length == 2 ? matches[ 1 ] : '';
         return theme;
       }