add skip navigation link

_layouts/home.html

@@ -22,7 +22,7 @@ layout: default
   </header>
 {% endif %}
 
-<main class="home" aria-label="Content">
+<main class="home" aria-label="Content" id="main">
 
   <h1 class="content-title divided">
     {% if site.paginate and site.paginate_path and paginator.page > 1 %}