diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 009d07e..8c76278 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2834,10 +2834,6 @@ function template_preprocess_page(&$variables) {
     $variables['main_menu'] = array(
       '#theme' =>'links__system_main_menu',
       '#links' => $variables['main_menu'],
-      '#attributes' => array(
-        'id' => 'main-menu',
-        'class' => array('links', 'inline', 'clearfix'),
-      ),
       '#heading' => array(
         'text' => t('Main menu'),
         'class' => array('element-invisible'),
@@ -2848,10 +2844,6 @@ function template_preprocess_page(&$variables) {
     $variables['secondary_menu'] = array(
       '#theme' =>'links__system_secondary_menu',
       '#links' => $variables['secondary_menu'],
-      '#attributes' => array(
-        'id' => 'secondary-menu',
-        'class' => array('links', 'inline', 'clearfix'),
-      ),
       '#heading' => array(
         'text' => t('Secondary menu'),
         'class' => array('element-invisible'),
diff --git a/core/modules/system/templates/html.html.twig b/core/modules/system/templates/html.html.twig
index 02a542b..38226db 100644
--- a/core/modules/system/templates/html.html.twig
+++ b/core/modules/system/templates/html.html.twig
@@ -37,11 +37,9 @@
     {{ scripts }}
   </head>
   <body{{ attributes }}>
-    <div id="skip-link">
       <a href="#main-content" class="element-invisible element-focusable">
         {{ 'Skip to main content'|t }}
       </a>
-    </div>
     {{ page_top }}
     {{ page }}
     {{ page_bottom }}
diff --git a/core/modules/system/templates/maintenance-page.html.twig b/core/modules/system/templates/maintenance-page.html.twig
index a57b546..1899bcf 100644
--- a/core/modules/system/templates/maintenance-page.html.twig
+++ b/core/modules/system/templates/maintenance-page.html.twig
@@ -13,80 +13,72 @@
  * @ingroup themeable
  */
 #}
-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
-  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
-<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="{{ language.langcode }}" lang="{{ language.langcode }}" dir="{{ language.dir }}">
-<head>
-  <title>{{ head_title }}</title>
+<!DOCTYPE html>
+<html>
   {{ head }}
+  <title>{{ head_title }}</title>
   {{ styles }}
   {{ scripts }}
 </head>
 <body class="{{ attributes.class }}">
-  <div id="page">
-    <div id="header">
-      <div id="logo-title">
-        {% if logo %}
-          <a href="{{ base_path }}" title="{{ 'Home'|t }}" rel="home" id="logo">
-            <img src="{{ logo }}" alt="{{ 'Home'|t }}" />
-          </a>
-        {% endif %}
 
-        <div id="name-and-slogan">
-          {% if site_name %}
-            <h1 id="site-name">
-              <a href="{{ base_path }}" title="{{ 'Home'|t }}" rel="home"><span>{{ site_name }}</span></a>
-            </h1>
-          {% endif %}
-          {% if site_slogan %}
-            <div id="site-slogan">{{ site_slogan }}</div>
-          {% endif %}
-        </div> <!-- /name-and-slogan -->
-      </div> <!-- /logo-title -->
+<div class="l-container">
 
-      {% if header %}
-        <div id="header-region">
-          {{ header }}
-        </div>
-      {% endif %}
+  <header role="banner">
+    {% if logo %}
+      <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home">
+        <img src="{{ logo }}" alt="{{ 'Home'|t }}"/>
+      </a>
+    {% endif %}
 
-    </div> <!-- /header -->
+    {% if site_name or site_slogan %}
+      <div class="name-and-slogan">
+        {% if site_name %}
+         <h1>
+           <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home" class="site-name">{{ site_name }}</a>
+         </h1>
+        {% endif %}
 
-    <div id="container" class="clearfix">
+        {% if site_slogan %}
+          <div class="site-slogan">{{ site_slogan }}</div>
+        {% endif %}
+      </div><!-- /.name-and-slogan -->
+    {% endif %}
 
-      {% if sidebar_first %}
-        <div id="sidebar-first" class="column sidebar">
-          {{ sidebar_first }}
-        </div> <!-- /sidebar-first -->
-      {% endif %}
+    {{ page.header }}
+  </header>
 
-      <div id="main" class="column"><div id="main-squeeze">
+  <div role="main">
+    {% if title %}
+      <h1>{{ title }}</h1>
+    {% endif %}
 
-        <div id="content">
-          {% if title %}<h1 class="title" id="page-title">{{ title }}</h1>{% endif %}
-          {% if messages %}{{ messages }}{% endif %}
-          <div id="content-content" class="clearfix">
-            {{ content }}
-          </div> <!-- /content-content -->
-        </div> <!-- /content -->
+    {% if messages %}
+      <div class="messages">{{ messages }}</div>
+    {% endif %}
 
-      </div></div> <!-- /main-squeeze /main -->
+    {{ page.content }}
+  </div>
 
-      {% if sidebar_second %}
-        <div id="sidebar-second" class="column sidebar">
-          {{ sidebar_second }}
-        </div> <!-- /sidebar-second -->
-      {% endif %}
+  {% if page.sidebar_first %}
+    <div class="l-sidebar-first">
+      {{ page.sidebar_first }}
+    </div><!-- /.l-sidebar-first -->
+  {% endif %}
 
-    </div> <!-- /container -->
+  {% if page.sidebar_second %}
+    <div class="l-sidebar-second">
+      {{ page.sidebar_second }}
+    </div><!-- /.l-sidebar-second -->
+  {% endif %}
 
-    <div id="footer-wrapper">
-      <div id="footer">
-        {% if footer %}{{ footer }}{% endif %}
-      </div> <!-- /footer -->
-    </div> <!-- /footer-wrapper -->
+  {% if page.footer %}
+    <footer role="contentinfo">
+      {{ page.footer }}
+    </footer>
+  {% endif %}
 
-  </div> <!-- /page -->
+</div><!-- /.l-container -->
 
 </body>
 </html>
diff --git a/core/modules/system/templates/page.html.twig b/core/modules/system/templates/page.html.twig
index ff7c010..7753c8d 100644
--- a/core/modules/system/templates/page.html.twig
+++ b/core/modules/system/templates/page.html.twig
@@ -66,39 +66,30 @@
  * @ingroup themeable
  */
 #}
-<div id="page">
-
-  <header id="header" role="banner" class="clearfix">
+<div class="l-container">
 
+  <header role="banner">
     {% if logo %}
-      <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home" id="logo">
+      <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home">
         <img src="{{ logo }}" alt="{{ 'Home'|t }}"/>
       </a>
     {% endif %}
 
     {% if site_name or site_slogan %}
-      <div id="name-and-slogan">
+      <div class="name-and-slogan">
         {% if site_name %}
-          {% if title %}
-            <p id="site-name"><strong>
-              <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home">{{ site_name }}</a>
-            </strong></p>
-          {# Use h1 when the content title is empty #}
-          {% else %}
-            <h1 id="site-name">
-              <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home">{{ site_name }}</a>
-            </h1>
-          {% endif %}
+         <h1>
+           <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home" class="site-name">{{ site_name }}</a>
+         </h1>
         {% endif %}
 
         {% if site_slogan %}
-          <p id="site-slogan">{{ site_slogan }}</p>
+          <div class="site-slogan">{{ site_slogan }}</div>
         {% endif %}
       </div><!-- /#name-and-slogan -->
     {% endif %}
 
     {{ page.header }}
-
   </header>
 
   {% if main_menu or secondary_menu %}
@@ -111,40 +102,59 @@
   {{ breadcrumb }}
 
   {% if messages %}
-    <div id="messages">{{ messages }}</div>
+    <div class="messages">{{ messages }}</div>
+  {% endif %}
+
+  {% if page.help %}
+    {{ page.help }}
   {% endif %}
 
-  <div id="main" role="main" class="clearfix">
-    <a id="main-content"></a>
+  <div role="main">
+    <a id="main-content"></a>{# link is in html.html.twig #}
+
+    <div class="l-content">
+
+      {% if page.highlighted %}
+        {{ page.highlighted }}
+      {% endif %}
 
-    <div id="content" class="column">
-      {% if page.highlighted %}<div id="highlighted">{{ page.highlighted }}</div>{% endif %}
       {{ title_prefix }}
-      {% if title %}<h1 class="title" id="page-title">{{ title }}</h1>{% endif %}
+      {% if title %}
+        <h1>{{ title }}</h1>
+      {% endif %}
       {{ title_suffix }}
-      {% if tabs %}<div class="tabs">{{ tabs }}</div>{% endif %}
-      {{ page.help }}
-      {% if action_links %}<ul class="action-links">{{ action_links }}</ul>{% endif %}
+
+      {% if tabs %}
+        <div class="tabs">{{ tabs }}</div>
+      {% endif %}
+
+      {% if action_links %}
+        <nav class="action-links">{{ action_links }}</nav>
+      {% endif %}
+
       {{ page.content }}
+
       {{ feed_icons }}
-    </div><!-- /#content -->
+    </div><!-- /.l-content -->
 
     {% if page.sidebar_first %}
-      <div id="sidebar-first" class="column sidebar">
+      <div class="l-sidebar-first">
         {{ page.sidebar_first }}
-      </div><!-- /#sidebar-first -->
+      </div><!-- /.l-sidebar-first -->
     {% endif %}
 
     {% if page.sidebar_second %}
-      <div id="sidebar-second" class="column sidebar">
+      <div class="l-sidebar-second">
         {{ page.sidebar_second }}
-      </div><!-- /#sidebar-second -->
+      </div><!-- /.l-sidebar-second -->
     {% endif %}
 
-  </div><!-- /#main -->
+  </div><!-- /role main -->
 
-  <footer id="footer" role="contentinfo">
-    {{ page.footer }}
-  </footer>
+  {% if page.footer %}
+    <footer role="contentinfo">
+      {{ page.footer }}
+    </footer>
+  {% endif %}
 
-</div><!-- /#page -->
+</div><!-- /.page -->
diff --git a/core/themes/bartik/bartik.theme b/core/themes/bartik/bartik.theme
index 0593a3c..1362e7e 100644
--- a/core/themes/bartik/bartik.theme
+++ b/core/themes/bartik/bartik.theme
@@ -50,6 +50,7 @@ function bartik_preprocess_page(&$variables) {
   }
   if (!empty($variables['secondary_menu'])) {
     $variables['secondary_menu']['#attributes']['id'] = 'secondary-menu-links';
+    $variables['secondary_menu']['#attributes']['class'] = array('links', 'inline', 'clearfix');
   }
 }
 
diff --git a/core/themes/stark/css/layout-rtl.css b/core/themes/stark/css/layout-rtl.css
index d5e9c6d..e1f6624 100644
--- a/core/themes/stark/css/layout-rtl.css
+++ b/core/themes/stark/css/layout-rtl.css
@@ -1,52 +1,52 @@
 @media all and (min-width: 480px) and (max-width: 959px) {
-  body.sidebar-first #content,
-  body.two-sidebars #content {
+  body.sidebar-first .l-content,
+  body.two-sidebars .l-content {
     float: left;
   }
-  body.sidebar-second #content {
+  body.sidebar-second .l-content {
     float: right;
   }
 
-  #sidebar-first {
+  .l-sidebar-first {
     float: right;
   }
 
-  #sidebar-second {
+  .l-sidebar-second {
     float: left;
   }
-  body.two-sidebars #sidebar-second {
+  body.two-sidebars .l-sidebar-second {
     float: right;
     clear: right;
   }
-  body.two-sidebars #sidebar-second .block {
+  body.two-sidebars .l-sidebar-second .block {
     float: right;
   }
 }
 
 @media all and (min-width: 960px) {
-  #content {
+  .l-content {
     float: right;
   }
-  body.sidebar-first #content {
+  body.sidebar-first .l-content {
     left: 0;
     right: 20%;
   }
-  body.two-sidebars #content {
+  body.two-sidebars .l-content {
     left: 0;
     right: 20%;
   }
 
-  #sidebar-first {
+  .l-sidebar-first {
     float: right;
     left: 0;
     right: -80%;
   }
-  body.two-sidebars #sidebar-first {
+  body.two-sidebars .l-sidebar-first {
     left: 0;
     right: -60%;
   }
 
-  #sidebar-second {
+  .l-sidebar-second {
     float: left;
   }
 }
diff --git a/core/themes/stark/css/layout.css b/core/themes/stark/css/layout.css
index 39f533b..536c3e8 100644
--- a/core/themes/stark/css/layout.css
+++ b/core/themes/stark/css/layout.css
@@ -9,12 +9,12 @@
  * This layout method works reasonably well, but shouldn't be used on a
  * production site because it can break. For example, if an over-large image
  * (one that is wider than 20% of the viewport) is in the left sidebar, the
- * image will overlap with the #content to the right.
+ * image will overlap with the .l-content to the right.
  */
 
-#content,
-#sidebar-first,
-#sidebar-second {
+.l-content,
+.l-sidebar-first,
+.l-sidebar-second {
   display: inline;
   position: relative;
 }
@@ -24,70 +24,75 @@ img {
   max-width: 100%;
 }
 
+header[role="banner"],
+footer[role="contentinfo"]{
+  clear:both;
+  width:100%
+}
 @media all and (min-width: 480px) and (max-width: 959px) {
-  #content {
+  .l-content {
     width: 100%;
   }
-  body.sidebar-first #content,
-  body.two-sidebars #content {
+  body.sidebar-first .l-content,
+  body.two-sidebars .l-content {
     width: 67%;
     float: right; /* LTR */
   }
-  body.sidebar-second #content {
+  body.sidebar-second .l-content {
     width: 67%;
     float: left; /* LTR */
   }
 
-  #sidebar-first {
+  .l-sidebar-first {
     width: 33%;
     float: left; /* LTR */
   }
 
-  #sidebar-second {
+  .l-sidebar-second {
     width: 33%;
     float: right; /* LTR */
   }
-  body.two-sidebars #sidebar-second {
+  body.two-sidebars .l-sidebar-second {
     clear: both;
     width: 100%;
   }
 
-  body.two-sidebars #sidebar-second .block {
+  body.two-sidebars .l-sidebar-second .block {
     float: left; /* LTR */
     width: 33%;
   }
-  body.two-sidebars #sidebar-second .block:nth-child(3n+1) {
+  body.two-sidebars .l-sidebar-second .block:nth-child(3n+1) {
     clear: both;
   }
 }
 
 @media all and (min-width: 960px) {
-  #content {
+  .l-content {
     width: 100%;
     float: left; /* LTR */
   }
-  body.sidebar-first #content {
+  body.sidebar-first .l-content {
     width: 80%;
     left: 20%; /* LTR */
   }
-  body.sidebar-second #content {
+  body.sidebar-second .l-content {
     width: 80%;
   }
-  body.two-sidebars #content {
+  body.two-sidebars .l-content {
     width: 60%;
     left: 20%; /* LTR */
   }
 
-  #sidebar-first {
+  .l-sidebar-first {
     width: 20%;
     float: left; /* LTR */
     left: -80%; /* LTR */
   }
-  body.two-sidebars #sidebar-first {
+  body.two-sidebars .l-sidebar-first {
     left: -60%; /* LTR */
   }
 
-  #sidebar-second {
+  .l-sidebar-second {
     float: right; /* LTR */
     width: 20%;
   }
