diff --git a/layouts/_default/baseof.html b/layouts/_default/baseof.html
index 44edc4a..ae3b9cc 100644
--- a/layouts/_default/baseof.html
+++ b/layouts/_default/baseof.html
@@ -7,7 +7,7 @@
   {{ partial "head.html" . }}
 </head>
 <body class="{{- ( or .Params.color $.Site.Params.ThemeColor ) -}}">
-{{ $container := cond $.Site.Params.FullWidthTheme "container full" (cond $.Site.Params.CenterTheme "container center" "container") }}
+{{ $container := cond ($.Site.Params.FullWidthTheme | default false) "container full" (cond ($.Site.Params.CenterTheme | default false) "container center" "container") }}
 
 <div class="{{- $container -}}{{- cond ($.Site.Params.oneHeadingSize | default true) " headings--one-size" "" }}">
 
