Complete inital re-design of client page

packages/sshecret-admin/src/sshecret_admin/frontend/templates/base/master-detail-email.html.j2

@@ -0,0 +1,26 @@
+{% extends 'base/page.html.j2' %}
+
+{% block page_content %}
+
+<!-- Master-Detail Split View -->
+<div class="flex h-[calc(100vh-8rem)] overflow-hidden">
+
+  <!-- Master Pane -->
+  <aside id="master-pane"
+         class="md:w-80 w-full shrink-0 border-r overflow-y-auto bg-white md:block border-gray-200 p-4">
+    {% block master %}
+      <p class="p-4 text-gray-500">Master view (e.g. list/tree)</p>
+    {% endblock %}
+  </aside>
+
+  <!-- Detail Pane -->
+  <section id="detail-pane"
+           class="flex-1 flex overflow-y-auto bg-white p-4 hidden md:block">
+    {% block detail %}
+      <p class="p-4 text-gray-500">Select an item to view details</p>
+    {% endblock %}
+  </section>
+
+</div>
+
+{% endblock %}