diff --git a/how-to-make-a-notebook-that/style.css b/how-to-make-a-notebook-that/style.css
index 8c3c9c1..346b4f2 100644
--- a/how-to-make-a-notebook-that/style.css
+++ b/how-to-make-a-notebook-that/style.css
@@ -217,11 +217,3 @@ section#main{
 
 }
 
-ext {
-    border-bottom-color: #a6dbf0;
-    background: linear-gradient(to bottom, #a6dbf0 100%, #a6dbf0 100%);
-    background-position: 0 100%;
-    background-repeat: repeat-x;
-    background-size: 0 0;
-    transition: background .2s ease-in-out;
-	}
\ No newline at end of file