update header

_includes/header.html

@@ -1,8 +1,8 @@
       <div id="header">
-	<div id="title">
+	<div id="title" class="wrapper">
 	  <h1><a href="{{ site.url }}">{{ site.title | default: site.github.repository_name }}</a></h1>
 	</div>
-	<div id="title">
+	<div id="title" class="wrapper">
 	  {% for my_page in site.pages %}
 	    {% if my_page.title %}
 	    <a href="{{ my_page.url | prepend: site.baseurl }}">{{ my_page.title }}</a>