Its possible to add some style to the form?

Hi @ssamuel68, you can target the form with the CSS and style it that way. Or what did you had in mind?

It would be very nice to have a Twig template file instead hard coded markup:

ProtectedPagesLoginForm.php

    $form['protected_page_enter_password']['protected_page_pid'] = [
      '#markup' => '<div class="protected_pages_description"><strong>' . $config->get('others.protected_pages_description') . '</strong></div>',
    ];

I would suggest something like:

<div class="protected-page">
    <div class="protected-page__description">
         {{ description }}
    </div>
    {{ form }} <-- class protected-page__form
</div>

This is an attempt to achieve the desired behaviour, where twig is present for the login form. So now the description is separated from the form (enter password) in a twig named protected-pages-login. (Like in the example above)

+++ b/templates/protected-pages-login.html.twig
@@ -0,0 +1,19 @@
+  <div class="protected_pages_description">

Looks good, only the class "protected_pages_description" doesn't fit Drupals BEM standard => protected-pages__description

Updated patch with the proposed BEM standard correction.

Updated patch with the correct proposed BEM standard correction.

This patch simply uses the form #theme with the existing structure, and try to be backward compatible.

Patch #8 is working nicely, Thanks!

Patch #7 and #8 working correctly, Thanks.

+1 RTBC huge help for theming and very standard, please consider adding to the module.