diff --git a/core.css b/core.css
index 3222ade..604a67d 100644
--- a/core.css
+++ b/core.css
@@ -179,6 +179,7 @@ pre {
    background: #CCC;
    border: 1px solid #888;
    border-radius: 4px;
+   overflow-x: scroll;
 }
 pre>code {
     color: #333;