Progressive Profiling on Non-Marketo pages

I'm trying to help my design team as they are struggling with enabling progressive profiling but keeping the same form design. 

Example:  we have fields currently side by side but once put into progressive in marketo, it no longer allows that and messes up on the landing page that sits outside of marketo.  Any suggestions on how to keep the side by side design and still have the form ask the appropriate fields?

Currently w/o pp:

(first name, last name)

With pp:

first name

last name