problem with copy of default model page.php

Hi,

I did make some modification to the helper-main-menu.php to show a different top main menu depending on the page model and all this work like a charm.

The problem I have is that after copying the page.php model to create a new page-entreprise.php model, the model load with some css trouble and seems boxed… Is there any modele related config to set to achieve a simple default model copy

I do use child theme and simply copied the page.php as page_entreprise.php and change header (added /* Template Name: Modèle Entreprise */) to create the new model page… Since this is really basic, I am pretty lost as why I do lose some css and boxed.

Thanks in advance