diff --git a/doc/formats/html/header.html b/doc/formats/html/header.html
index e6bba6932..171abf524 100644
--- a/doc/formats/html/header.html
+++ b/doc/formats/html/header.html
@@ -5,7 +5,7 @@
 <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
 <meta http-equiv="X-UA-Compatible" content="IE=9"/>
 <meta name="generator" content="Doxygen $doxygenversion"/>
-<meta name="viewport" content="width=device-width, initial-scale=1.25">
+<meta name="viewport" content="width=device-width, initial-scale=1">
 <!--BEGIN PROJECT_NAME--><title>$projectname: $title</title><!--END PROJECT_NAME-->
 <!--BEGIN !PROJECT_NAME--><title>$title</title><!--END !PROJECT_NAME-->
 <link href="$relpath^tabs.css" rel="stylesheet" type="text/css"/>