Padding REM vs PERCENTAGE Client-First

I have been implementing Finsweet Client-First approach since we have a huge site with multiple Landing pages.

The structure states to use REM units for global padding as well. How does that translate if someone increases their base font size in their browser? Will that result in not only a larger font size in typography but also increased horizontal padding if we use REM units there too? Will that make margins too wide or high? scatching my head on this one.

Here is my site Read-Only: LINK
(how to share your site Read-Only link)