diff --git a/app/templates/views/email-branding/select-branding.html b/app/templates/views/email-branding/select-branding.html
index e33cbcaa4..a15a86b2e 100644
--- a/app/templates/views/email-branding/select-branding.html
+++ b/app/templates/views/email-branding/select-branding.html
@@ -11,7 +11,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">{{ page_title }}</h1>
+  <h1 class="font-body-2xl">{{ page_title }}</h1>
   {{ live_search(target_selector='.email-brand', show=True, form=search_form, autofocus=True) }}
   <nav>
     {% for brand in email_brandings %}
diff --git a/app/templates/views/find-services/find-services-by-name.html b/app/templates/views/find-services/find-services-by-name.html
index 0be551043..336cb41eb 100644
--- a/app/templates/views/find-services/find-services-by-name.html
+++ b/app/templates/views/find-services/find-services-by-name.html
@@ -9,7 +9,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Find services by name
   </h1>
 
diff --git a/app/templates/views/find-users/find-users-by-email.html b/app/templates/views/find-users/find-users-by-email.html
index 7d7c644c3..a52c76d0e 100644
--- a/app/templates/views/find-users/find-users-by-email.html
+++ b/app/templates/views/find-users/find-users-by-email.html
@@ -9,7 +9,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Find users by email
   </h1>
 
diff --git a/app/templates/views/inbound-sms-admin.html b/app/templates/views/inbound-sms-admin.html
index c5d9da9fb..a9b8c36d4 100644
--- a/app/templates/views/inbound-sms-admin.html
+++ b/app/templates/views/inbound-sms-admin.html
@@ -20,7 +20,7 @@ Inbound SMS
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Inbound SMS
   </h1>
 
diff --git a/app/templates/views/jobs/jobs.html b/app/templates/views/jobs/jobs.html
index 36c430321..4ae847a5e 100644
--- a/app/templates/views/jobs/jobs.html
+++ b/app/templates/views/jobs/jobs.html
@@ -7,7 +7,7 @@
 {% endblock %}
 
 {% block maincolumn_content %}
-    <h1 class="heading-medium">Uploads</h1>
+    <h1 class="font-body-2xl">Uploads</h1>
     <div class="dashboard">
       {% if jobs %}
         {% include 'views/dashboard/_jobs.html' %}
diff --git a/app/templates/views/organizations/index.html b/app/templates/views/organizations/index.html
index baae10216..d8811d00a 100644
--- a/app/templates/views/organizations/index.html
+++ b/app/templates/views/organizations/index.html
@@ -8,7 +8,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">Organizations</h1>
+  <h1 class="font-body-2xl">Organizations</h1>
 
   {{ live_search(target_selector='.browse-list-item', show=True, form=search_form, label='Search by name') }}
 
diff --git a/app/templates/views/organizations/organization/settings/index.html b/app/templates/views/organizations/organization/settings/index.html
index 2f3ac9ca1..50bee3109 100644
--- a/app/templates/views/organizations/organization/settings/index.html
+++ b/app/templates/views/organizations/organization/settings/index.html
@@ -6,7 +6,7 @@
 {% endblock %}
 
 {% block maincolumn_content %}
-  <h1 class="heading-medium">Settings</h1>
+  <h1 class="font-body-2xl">Settings</h1>
   <div class="bottom-gutter-3-2 settings-table body-copy-table">
     {% call mapping_table(
       caption='General',
diff --git a/app/templates/views/organizations/organization/trial-mode-services.html b/app/templates/views/organizations/organization/trial-mode-services.html
index 0f414b71d..4f18cdf33 100644
--- a/app/templates/views/organizations/organization/trial-mode-services.html
+++ b/app/templates/views/organizations/organization/trial-mode-services.html
@@ -7,7 +7,7 @@
 
 {% block maincolumn_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Trial mode services
   </h1>
   {{ live_search(target_selector='.browse-list-item', show=True, form=search_form, label='Search by name') }}
diff --git a/app/templates/views/organizations/organization/users/index.html b/app/templates/views/organizations/organization/users/index.html
index e724dc84d..84e444c93 100644
--- a/app/templates/views/organizations/organization/users/index.html
+++ b/app/templates/views/organizations/organization/users/index.html
@@ -19,7 +19,7 @@
     ) }}
   {% endif %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Team members
   </h1>
 
diff --git a/app/templates/views/platform-admin/_base_template.html b/app/templates/views/platform-admin/_base_template.html
index 75696fabc..7a54c8ff3 100644
--- a/app/templates/views/platform-admin/_base_template.html
+++ b/app/templates/views/platform-admin/_base_template.html
@@ -3,40 +3,48 @@
 
 {% block main %}
 <div class="grid-container">
-    <div class="navigation-service usa-breadcrumb">
-      <div class="navigation-service usa-breadcrumb-name govuk-!-font-weight-bold">
-        Platform admin
-      </div>
-      <a href="{{ url_for('main.choose_account') }}" class="usa-link navigation-service usa-breadcrumb-switch">Switch service</a>
-    </div>
-    <div class="grid-row">
-      <div class="tablet:grid-col-2">
+    <nav class="navigation-service usa-breadcrumb">
+      <ol class="usa-breadcrumb__list">
+        <li class="usa-breadcrumb__list-item">
+          <span class="usa-breadcrumb__label">Platform admin</span>
+        </li>
+        <li class="usa-breadcrumb__list-item">
+          <a class="usa-breadcrumb__link" href="{{ url_for('main.choose_account') }}">
+            <span class="usa-breadcrumb__label">Switch service</span>
+          </a>
+        </li>
+      </ol>
+    </nav>
+    <div class="grid-row margin-bottom-10">
+      <div class="tablet:grid-col-3 margin-top-4">
         <nav class="navigation">
+          <ul class="usa-sidenav">
             {% for link_text, url in [
-            ('Summary', url_for('main.platform_admin')),
-            ('Live services', url_for('main.live_services')),
-            ('Trial mode services', url_for('main.trial_services')),
-            ('Organizations', url_for('main.organizations')),
-            ('Providers', url_for('main.view_providers')),
-            ('Reports', url_for('main.platform_admin_reports')),
-            ('Email branding', url_for('main.email_branding')),
-            ('Inbound SMS numbers', url_for('main.inbound_sms_admin')),
-            ('Find services by name', url_for('main.find_services_by_name')),
-            ('Find users by email', url_for('main.find_users_by_email')),
-            ('Email complaints', url_for('main.platform_admin_list_complaints')),
-            ('Clear cache', url_for('main.clear_cache')),
-          ] %}
-            <li>
-              <a class="usa-link" href="{{ url }}">
-                {{ link_text }}
+              ('Summary', ('main.platform_admin')),
+              ('Live services', ('main.live_services')),
+              ('Trial mode services', ('main.trial_services')),
+              ('Organizations', ('main.organizations')),
+              ('Providers', ('main.view_providers')),
+              ('Reports', ('main.platform_admin_reports')),
+              ('Email branding', ('main.email_branding')),
+              ('Inbound SMS numbers', ('main.inbound_sms_admin')),
+              ('Find services by name', ('main.find_services_by_name')),
+              ('Find users by email', ('main.find_users_by_email')),
+              ('Email complaints', ('main.platform_admin_list_complaints')),
+              ('Clear cache', ('main.clear_cache')),
+            ] %}
+            <li class="usa-sidenav__item">
+              <a class="{% if url == request.endpoint %} usa-current {% endif %}" href="{{ url_for(url) }}">
+                <span class="usa-sidenav__label">{{ link_text }}</span>
               </a>
             </li>
           {% endfor %}
+          </ul>
         </nav>
       </div>
-      <div class="grid-col-10 tablet:grid-col-10">
+      <div class="grid-col-9 tablet:grid-col-9 padding-left-4 sub-content">
       {% block backLink %}{% endblock %}
-        <main class="govuk-main-wrapper column-main govuk-!-padding-top-0 govuk-!-padding-bottom-0" id="main-content" role="main">
+        <main id="main-content" role="main">
           {% block content %}
             {% include 'flash_messages.html' %}
             {% block platform_admin_content %}{% endblock %}
diff --git a/app/templates/views/platform-admin/clear-cache.html b/app/templates/views/platform-admin/clear-cache.html
index 52e7666ce..d2bfe34b8 100644
--- a/app/templates/views/platform-admin/clear-cache.html
+++ b/app/templates/views/platform-admin/clear-cache.html
@@ -8,7 +8,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Clear cache
   </h1>
 
diff --git a/app/templates/views/platform-admin/complaints.html b/app/templates/views/platform-admin/complaints.html
index b504c2ae5..10cf18fef 100644
--- a/app/templates/views/platform-admin/complaints.html
+++ b/app/templates/views/platform-admin/complaints.html
@@ -9,7 +9,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Email complaints
   </h1>
 
diff --git a/app/templates/views/platform-admin/index.html b/app/templates/views/platform-admin/index.html
index ee2e53e71..be5fbd6f4 100644
--- a/app/templates/views/platform-admin/index.html
+++ b/app/templates/views/platform-admin/index.html
@@ -11,7 +11,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Summary
   </h1>
 
diff --git a/app/templates/views/platform-admin/reports.html b/app/templates/views/platform-admin/reports.html
index bdc2d298e..f22faa728 100644
--- a/app/templates/views/platform-admin/reports.html
+++ b/app/templates/views/platform-admin/reports.html
@@ -6,7 +6,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Reports
   </h1>
 
diff --git a/app/templates/views/platform-admin/services.html b/app/templates/views/platform-admin/services.html
index db24ccdee..adaf5be33 100644
--- a/app/templates/views/platform-admin/services.html
+++ b/app/templates/views/platform-admin/services.html
@@ -57,7 +57,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     {{ page_title|capitalize }}
   </h1>
 
diff --git a/app/templates/views/platform-admin/splash-page.html b/app/templates/views/platform-admin/splash-page.html
index 89bd77ff1..0dcee97ca 100644
--- a/app/templates/views/platform-admin/splash-page.html
+++ b/app/templates/views/platform-admin/splash-page.html
@@ -6,7 +6,7 @@
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">
+  <h1 class="font-body-2xl">
     Summary
   </h1>
 
diff --git a/app/templates/views/providers/providers.html b/app/templates/views/providers/providers.html
index aa0f578df..ba98608a7 100644
--- a/app/templates/views/providers/providers.html
+++ b/app/templates/views/providers/providers.html
@@ -8,7 +8,7 @@ Providers
 
 {% block platform_admin_content %}
 
-  <h1 class="heading-medium">Providers</h1>
+  <h1 class="font-body-2xl">Providers</h1>
 
   <h2 class="font-body-lg">SMS</h2>