I've been analyzing my pages using browser developer tools to find out how I can reduce the margins of standard Joomla article pages to match the margins of SP Page Builder pages, but only on part of the page. 
My site is built using Helix Ultimate and SP Page Builder 5. Some pages are built using SPPB, some show Joomla articles on the standard Joomla pages (formatted by Helix Ultimate).
All pages have to show a "sponsor block" at the bottom of the page, just above the footer. This block is build using an SPPB Module, positioned at "content-bottom".
This all works nicely, except for the margins for that "sponsor block". Here is a visualization
This is how a SPPB page is shown:
The margins/paddings match the that of the header (red double arrow line). This section has a grey background, which illustrates that the content extends to the "max-width" of the page (red circled areas).
The "sponsor block", which is built via SPPB site module, looks like this when shown on a SPPB page:
The padding (red double arrowed line) matches that of the SPPB page shown above that block. Also the gray background extends to the "max-width" (red circles) the same as the SPPB page content above.
The module definition:

Now, this image show the upper part of a plain Joomla article displayed using as standard Joomla page:
Again the margins/padding is highlighed by the red double arrowd line. It matches how the SPPB page is shown
And here is "Sponsor block" as it appears on such standard Joomla pages, i.e. non-SPPB pages:
As you cab see, there is an unwanted white bar on the left and right side of the module (red double arrows line). 
I would want the grey background of the module to extend to max-width here too.
I couldn't find any hint on what custom CSS I should add. I also tried to placde the module at other positions. And, I also tried to add an additional section in the Helix Ultimate layout. 
Can youn help me out?