diff --git a/core/modules/system/css/system.admin.css b/core/modules/system/css/system.admin.css
index 2612d9f..0020462 100644
--- a/core/modules/system/css/system.admin.css
+++ b/core/modules/system/css/system.admin.css
@@ -14,7 +14,6 @@ div.admin-panel .description {
   margin: 0 0 3px;
   padding: 2px 0 3px 0;
 }
-
 div.admin .expert-link {
   text-align: right; /* LTR */
   margin-right: 1em; /* LTR */
diff --git a/core/modules/system/templates/admin-page.html.twig b/core/modules/system/templates/admin-page.html.twig
index 73cae67..88f342a 100644
--- a/core/modules/system/templates/admin-page.html.twig
+++ b/core/modules/system/templates/admin-page.html.twig
@@ -16,8 +16,8 @@
 #}
 <div class="admin clearfix">
   {{ system_compact_link }}
-  {% for position, container in containers %}
-    <div class="{{ position }} clearfix">
+  {% for container in containers %}
+    <div class="l-column half clearfix">
       {% for block in container.blocks %}
         {{ block }}
       {% endfor %}
diff --git a/core/themes/seven/templates/maintenance-page.html.twig b/core/themes/seven/templates/maintenance-page.html.twig
index dc691c1..e3d9ada 100644
--- a/core/themes/seven/templates/maintenance-page.html.twig
+++ b/core/themes/seven/templates/maintenance-page.html.twig
@@ -24,20 +24,20 @@
   {{ page_top }}
 
   <header id="branding">
-    <div class="branding__inner">
+    <div class="l-container">
       {% if title %}<h1 class="page-title">{{ title }}</h1>{% endif %}
     </div>
   </header>
 
-  <div id="page">
-    <div id="sidebar-first" class="sidebar">
+  <div id="page" class="l-container">
+    <div id="sidebar-first" class="l-column quarter sidebar">
       {% if logo %}
         <img id="logo" src="{{ logo }}" alt="{{ site_name }}" />
       {% endif %}
       {{ sidebar_first }}
     </div>
 
-    <main id="content" class="clearfix">
+    <main id="content" class="l-column three-quarter clearfix">
       {% if messages %}
         <div id="console">{{ messages }}</div>
       {% endif %}