diff --git a/source/css/_components/md.styl b/source/css/_components/md.styl
index 75f00db..d941f20 100644
--- a/source/css/_components/md.styl
+++ b/source/css/_components/md.styl
@@ -103,6 +103,8 @@
 .md-text pre
   -webkit-font-smoothing: auto
   -moz-osx-font-smoothing: auto
+  &.mermaid
+    overflow: auto
 
 .md-text
   .center