Specify gitlab nav

app/assets/stylesheets/framework/gitlab-theme.scss

@@ -5,7 +5,7 @@
 @mixin gitlab-theme($color-100, $color-200, $color-500, $color-700, $color-800, $color-900, $color-alternate) {
   // Header
 
-  header {
+  .navbar-gitlab {
     background-color: $color-900;
 
     .navbar-collapse {
@@ -200,9 +200,9 @@ body {
   &.ui_light {
     @include gitlab-theme($theme-gray-900, $theme-gray-700, $theme-gray-800, $theme-gray-700, $theme-gray-700, $theme-gray-100, $theme-gray-700);
 
-    header {
+    .navbar-gitlab {
       background-color: $theme-gray-100;
-      box-shadow: 0 2px 0 0 $border-color;
+      box-shadow: 0 1px 0 0 $border-color;
 
       .logo-text svg {
         fill: $theme-gray-900;

app/assets/stylesheets/framework/header.scss

@@ -2,7 +2,7 @@
   margin-top: $header-height;
 }
 
-header {
+.navbar-gitlab {
   @include new-style-dropdown;
 
   &.navbar-empty {
@@ -508,7 +508,7 @@ header {
 }
 
 @media (max-width: $screen-xs-max) {
-  header .container-fluid {
+  .navbar-gitlab .container-fluid {
     font-size: 18px;
 
     .navbar-nav {
@@ -567,6 +567,6 @@ header {
   border: 1px solid $avatar-border;
 }
 
-.with-performance-bar header.navbar-gitlab {
+.with-performance-bar .navbar-gitlab {
   top: $performance-bar-height;
 }