procedure_context: hide the description on auth pages

app/assets/stylesheets/new_design/auth.scss

@@ -3,6 +3,19 @@
 @import "placeholders";
 @import "mixins";
 
+#auth {
+  // On small screens, hide the procedure description text on auth pages.
+  // It avoids pushing the sign-in/sign-up form out of the viewport.
+  //
+  // The procedure description can still be read from the /commencer
+  // pages.
+  @media (max-width: $two-columns-breakpoint) {
+    .procedure-description {
+      display: none;
+    }
+  }
+}
+
 .auth-form {
   .auth-options {
     display: flex;

app/views/layouts/application.html.haml

@@ -23,7 +23,7 @@
     - if Rails.env.development?
       = stylesheet_link_tag :xray
 
-  %body{ class: browser.platform.ios? ? 'ios' : nil }
+  %body{ id: content_for(:page_id), class: browser.platform.ios? ? 'ios' : nil }
     .page-wrapper
       = render partial: "layouts/outdated_browser_banner"
       = render partial: 'layouts/pre_maintenance'

app/views/users/registrations/new.html.haml

@@ -1,3 +1,5 @@
+= content_for(:page_id, 'auth')
+
 .auth-form
   = devise_error_messages!
   = form_for resource, url: user_registration_path, html: { class: "form" } do |f|

app/views/users/sessions/new.html.haml

@@ -1,3 +1,5 @@
+= content_for(:page_id, 'auth')
+
 .auth-form.sign-in-form
   - if resource_name == :user
     %p.register