Add maximum content width

Help with readability of the website on large screens.

templates/page.tpl.html

@@ -37,6 +37,7 @@
 	<hr class="no-css">
 </div>
 <header role="banner">
+<div class="bounding-box">
   <hgroup id="title">
 	  <h1 id="site_acronym"><a href="<!--% absolute_path(baseurl) %-->index.html">HPR</a></h1>
       <p id="site_name">
@@ -50,6 +51,7 @@
 	<p id="tag2">Sharing your ideas, projects, opinions since 2005</p>
     <p id="tag3">New episodes every weekday </p>
   </hgroup>
+</div>
 </header>
 <main id="main_content" role="main">
 <!--% INCLUDE $content %-->