Quick content folding demo with no regions - a little work around with percentage ratio padding and absolute positioning.
Resize to see.
Ad folding was one good use case of why css regions would be a much needed feature to solve some responsive problems - it was added and removed from chrome.
Regions would be rather handy to have but you can sometimes use work arounds in situations like this one where I'm' using ratios along with padding-top and position:absolute which gives the desired outcome. It just isn't as flexible as the preposed regions solutions.
A little word of warning this example code likely could be cleaner and is mainly a proof of concept so yer!
Lorem ipsum dolor sit amet, consectetur adipisicing elit.
Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. Mauris placerat eleifend leo. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante.