Bitrix + PhoneGap application development?

Question

css

Hello!
The essence of the question is as follows:
There is an online store website on 1C-Bitrix. Now we need to write an application.
With the help of HTML/CSS/JS + Framework7, I laid out the layout of the application, created all the main pages, threw in demo content, compiled PhoneGap 'om - everything is in order.
How can this layout, where all the main pages are created, be "pulled" onto Bitrix?
Is knowledge of HTML/CSS/JS and quite a bit of PHP enough to make a full-featured online store application with authorization, a personal account, a catalog?
Or is it better to pay a developer who will do everything competently?