diff --git a/modules/symfony_mailer_bc/symfony_mailer_bc.libraries.yml b/modules/symfony_mailer_bc/symfony_mailer_bc.libraries.yml
index 1c37c4e..745e25c 100644
--- a/modules/symfony_mailer_bc/symfony_mailer_bc.libraries.yml
+++ b/modules/symfony_mailer_bc/symfony_mailer_bc.libraries.yml
@@ -1,4 +1,4 @@
 contact:
   css:
     theme:
-      css/contact.email.css: {}
+      css/contact.email.css: { preprocess: false }