diff --git a/docs/user/book.css b/docs/user/book.css
index 649b285599b..e5d0fc4e3d8 100644
--- a/docs/user/book.css
+++ b/docs/user/book.css
@@ -480,7 +480,7 @@ div.fragment pre.fragment {
 	font-family: "Deja Vu Mono", Courier, "Courier New", monospace, fixed;
 	font-weight: normal;
 	font-style: normal;
-	font-size: 0.9em;
+	font-size: 13px;
 	line-height: 1.3;
 }
 div.fragment pre.fragment a.code {