diff --git a/lib/config.php b/lib/config.php
index 18132c3..6bb9f0f 100644
--- a/lib/config.php
+++ b/lib/config.php
@@ -21,10 +21,10 @@ define('POST_EXCERPT_LENGTH', 40);
 function roots_main_class() {
   if (roots_display_sidebar()) {
     // Classes on pages with the sidebar
-    $class = 'col-sm-8 col-md-8 col-lg-8';
+    $class = 'col-sm-8';
   } else {
     // Classes on full width pages
-    $class = 'col-lg-12';
+    $class = 'col-sm-12';
   }
 
   return $class;
@@ -34,7 +34,7 @@ function roots_main_class() {
  * .sidebar classes
  */
 function roots_sidebar_class() {
-  return 'col-sm-4 col-md-4 col-lg-4';
+  return 'col-sm-4';
 }
 
 /**
diff --git a/templates/header-top-navbar.php b/templates/header-top-navbar.php
index af610a6..7589fe8 100644
--- a/templates/header-top-navbar.php
+++ b/templates/header-top-navbar.php
@@ -1,4 +1,4 @@
-<header class="banner navbar navbar-static-top" role="banner">
+<header class="banner navbar navbar-default navbar-static-top" role="banner">
   <div class="container">
     <div class="navbar-header">
       <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">