diff --git a/core/themes/bartik/bartik.libraries.yml b/core/themes/bartik/bartik.libraries.yml
index f796093..a273f96 100644
--- a/core/themes/bartik/bartik.libraries.yml
+++ b/core/themes/bartik/bartik.libraries.yml
@@ -49,7 +49,7 @@ messages:
   version: VERSION
   css:
     theme:
-      css/components/messages.css: {}
+      css/components/messages.css: { preprocess: false }
 
 color.preview:
   version: VERSION