diff --git a/app/frontend/styles/_header.scss b/app/frontend/styles/_header.scss
index 924276d5f..a9954494b 100644
--- a/app/frontend/styles/_header.scss
+++ b/app/frontend/styles/_header.scss
@@ -1,6 +1,4 @@
 .app-header {
-  border-bottom: govuk-spacing(2) solid $govuk-brand-colour;
-
   .govuk-header__logo {
     @include govuk-media-query($from: desktop) {
       width: 60%;
@@ -22,11 +20,3 @@
   }
 }
 
-.app-header--orange,
-.app-header--orange .govuk-header__container {
-  border-bottom-color: govuk-colour("orange");
-}
-
-.app-header__no-border-bottom {
-  border-bottom: 0;
-}
diff --git a/app/frontend/styles/application.scss b/app/frontend/styles/application.scss
index 33574bf9b..03efff357 100644
--- a/app/frontend/styles/application.scss
+++ b/app/frontend/styles/application.scss
@@ -130,3 +130,15 @@ $govuk-breakpoints: (
   left: -15px;
   position: relative;
 }
+
+.app-main-service-navigation {
+  border-bottom: govuk-spacing(2) solid $govuk-brand-colour;
+}
+
+.app-service-navigation--orange {
+  border-bottom-color: govuk-colour("orange");
+}
+
+.app-service-navigation--no-border {
+  border-bottom: 0;
+}
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 5a9203da8..2bf119e5a 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -10,14 +10,11 @@ module ApplicationHelper
     end
   end
 
-  def govuk_header_classes(current_user)
-    if current_user&.support?
-      "app-header app-header--orange"
-    elsif notifications_to_display?
-      "app-header app-header__no-border-bottom"
-    else
-      "app-header"
-    end
+  def govuk_service_navigation_classes(current_user)
+    return "app-service-navigation--orange" if current_user&.support?
+    return "app-service-navigation--no-border" if notifications_to_display?
+
+    ""
   end
 
   def govuk_phase_banner_tag(current_user)
diff --git a/app/views/layouts/application.html.erb b/app/views/layouts/application.html.erb
index 622f7ebf0..3afcddece 100644
--- a/app/views/layouts/application.html.erb
+++ b/app/views/layouts/application.html.erb
@@ -81,13 +81,14 @@
     <%= govuk_skip_link %>
 
     <%= govuk_header(
-      classes: govuk_header_classes(current_user),
+      classes: "app-header",
       homepage_url: root_path,
     ) %>
 
     <%= govuk_service_navigation(
       service_name: t("service_name"),
       service_url: root_path,
+      classes: "app-main-service-navigation #{govuk_service_navigation_classes(current_user)}",
     ) do |component| %>
       <% unless FeatureToggle.service_moved? || FeatureToggle.service_unavailable? %>
         <% if current_user.nil? %>
diff --git a/app/views/layouts/rails_admin/_navigation.html.erb b/app/views/layouts/rails_admin/_navigation.html.erb
index cf0fdeaed..ef178e4b1 100644
--- a/app/views/layouts/rails_admin/_navigation.html.erb
+++ b/app/views/layouts/rails_admin/_navigation.html.erb
@@ -1,11 +1,12 @@
 <%= govuk_header(
-      classes: "app-header app-header--orange",
+      classes: "app-header",
       homepage_url: Rails.application.routes.url_helpers.root_path,
     ) %>
 
 <%= govuk_service_navigation(
       service_name: t("service_name"),
       service_url: Rails.application.routes.url_helpers.root_path,
+      classes: "app-main-service-navigation app-service-navigation--orange",
     ) do |component| %>
       <%= component.with_navigation_item(text: "Your account", href: Rails.application.routes.url_helpers.account_path) %>
       <%= component.with_navigation_item(text: "Sign out", href: Rails.application.routes.url_helpers.destroy_user_session_path) %>