diff --git a/themes/oni/css/style.css b/themes/oni/css/style.css
index 1305ee5..f002d4c 100644
--- a/themes/oni/css/style.css
+++ b/themes/oni/css/style.css
@@ -84,7 +84,7 @@ ul.tags li a {
 
 pre.src {
     position: relative;
-    overflow: visible;
+    overflow: auto;
 }
 pre.src:before {
     display: none;