Finalize the layout of the site on cms Bitrix (layout designer)

Edit
the site cmpnnt.com made on the Phoenix template. Everything needs to be done adaptively, cross-browser, so that it does not fly off when updating Bitrix, modules, template
1) Basement make as in the photo
2) the product page should look like in the photo. Now there is only 1 product on the site, so the client asked to display it as a Store, then there will be a separate store page
at the same time, the properties under the photo should open like an accordion
3) Q&A page:
Either a completely new option is possible, in which the form works without pop-up messages immediately on the page:
Or a variant implemented in the same way as in the site template, but with a different design:
4) center the header on the inner pages
Red highlights the place where the menu should be located to be in the center of the page: