use :has selectors for search input

app/views/templates_archived/index.html.erb

@@ -4,8 +4,8 @@
     <span style="margin-left: 3px"><%= t('back_to_active') %></span>
   <% end %>
 </div>
-<div class="flex justify-between mb-4 items-center">
-  <div>
+<div class="group/header flex justify-between mb-4 items-center">
+  <div class="max-md:group-has-[search-input:focus-within]/header:hidden">
     <h1 class="text-2xl md:text-3xl font-bold md:block <%= 'hidden' if params[:q].present? %>"><%= t('document_templates_html') %> <span class="badge badge-outline badge-lg align-middle"><%= t('archived') %></span></h1>
   </div>
   <% if params[:q].present? || @pagy.pages > 1 %>