diff --git a/sass/_vendor.scss b/sass/_vendor.scss
index 66a158b..06535b9 100644
--- a/sass/_vendor.scss
+++ b/sass/_vendor.scss
@@ -298,7 +298,7 @@ a:hover {
 }
 
 .hack pre code:after, .hack pre code:before {
-  content: ''
+  content: none
 }
 
 .hack code {