diff --git a/css/main.css b/css/main.css
index 440f5e13..8b4d05a8 100644
--- a/css/main.css
+++ b/css/main.css
@@ -721,7 +721,7 @@ color: #f6f6f7;
 }
 
 /* Ace Editor Settings */
-body > div:not[class]:last-of-type {
+body > div:not([class]):last-of-type {
   background: rgba(0,0,0, 0.7)!important;
 }