diff --git a/lib/rdoc/generator/template/snapper/css/snapper.css b/lib/rdoc/generator/template/snapper/css/snapper.css
index 3b449e270c..ff0dc56871 100644
--- a/lib/rdoc/generator/template/snapper/css/snapper.css
+++ b/lib/rdoc/generator/template/snapper/css/snapper.css
@@ -111,6 +111,7 @@ code {
 pre {
     padding: calc(var(--space) / 2);
     border: 1px solid #DFDFE8;
+    overflow-x: auto;
 }
 
 code {