Updated the normalise css.

sass/navigation/mobile/_mobile.scss

@@ -18,7 +18,7 @@
   position: absolute;
   width: 100vw;
   height: 100vh;
-  background-color: rgba(color('black'), .2);
+  background-color: color(mobile-menu-cover);
   opacity: 0;
 
   .js-nav-open & {
@@ -86,7 +86,7 @@
       margin: .4rem 0;
 
       a {
-        color: color(white);
+        color: color('white');
         text-decoration: none;
       }
     }

sass/navigation/more-link/_more-link.scss

@@ -1,6 +1,6 @@
 // "More" link
 //
-// Styles the "Read more…" and "Help" links common on the web.
+// Styles the "Read more…" and "Help" links common in Drupal.
 //
 // Markup: more-link.twig
 //
@@ -26,3 +26,15 @@
     }
   }
 }
+
+//
+// Drupal selectors.
+//
+
+.more-help-link {
+  @extend %more-link;
+
+  a {
+    @extend %more-link__help-icon;
+  }
+}

sass/navigation/navbar/_navbar.scss

@@ -4,10 +4,6 @@
 // Navbar
 //
 // A simple method to get navigation links to appear in one line.
-//
-// Markup: navbar.twig
-//
-// Style guide: navigation.navbar
 
 .navbar,
 %navbar {
@@ -33,3 +29,21 @@
     }
   }
 }
+
+//
+// Drupal selectors.
+//
+
+.main-navigation {
+  // Hide the block titles put into the main-navigation area of the page.tpl.php.
+  .block-menu .block__title,
+  .block-menu-block .block__title {
+    @extend %visually-hidden;
+  }
+
+  // Main menu and secondary menu links and menu block links.
+  .links,
+  .menu {
+    @extend %navbar;
+  }
+}

sass/navigation/pager/_pager.scss

@@ -2,10 +2,6 @@
 //
 // Paged navigation is a list of page numbers when more than 1 page of content
 // is available.
-//
-// Markup: pager.twig
-//
-// Style guide: navigation.pager
 
 .pager,
 %pager {
@@ -31,7 +27,7 @@
 }
 
 //
-// Zen selectors.
+// Drupal selectors.
 //
 
 // .pager-item     - A list item containing a page number in the list of pages.