It is working in 3.1 but only if you have full browser width available.
If space available is as narrow as the responsive mechanism works then the ribbon is clipped on left top sides.
It can be seen on the NeoFashion demo site as well. Just switch to the dresses category and resize browser window so the filters will be moved down. You will notice clipping left and top effect on Party Lace Dress product and top clipping on other products in the first row.
There is also problem with ribbon in product details - sometimes ribbon seems to be detached from the picture when the browser window is resized - this sometimes produces weird effects.
Again check the Party Lace product in demo.
Ribbon should be scalled and positioned as the picture is.
Another 5-cents to the responsive mechanizm: Try resizing main demo page, so that you will have 2 products in the bestsellers row.
- why are the BUY NOW bigger (not smaller or at least equal) ) then before
- if you scroll down then you'll notice BUY NOW buttons overlapping other products and images carousell.
And finally at my site in Polish (http://www.elegantis.pl
) if you resize non empty cart then instead of table headings you'll have mysterious numbers (set by data-title attributes of <td> tags). Same effect can be noticed in the resized comparision page.