add initial scale

layouts/partials/head.html

@@ -1,5 +1,5 @@
 <meta charset="utf-8">
-<meta name="viewport" content="width=device-width">
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>{{ if .IsHome }}{{ site.Title }}{{ else }}{{ printf "%s | %s" .Title site.Title }}{{ end }}</title>
 {{- partialCached "head/css.html" . }}
 <link rel="shortcut icon" href="{{ site.Params.meta.favicon }}">