silverstripe-webpack/site/templates/Includes/Content.ss

<div class="page-content">
	<h1 class="page-header">$Title</h1>

	<div class="page-content">
        $ElementalArea

        <% if $Form %>
        <div class="container">
            $Form
        </div>
        <% end_if %>
	</div>
	
</div>