i'm sorry, you nust fix the product to save competabilty to perevious version...
i'm not going to change several projects on several customers every time you releas version without considering previous developments.
your request to change the CSS is not acceptable,
for me, CSS is "gibrish" and (without Lena interference), you could even answer that it's not part of your change... and for sure the problem is because of the developer action...i could not prove otherwise...
For best results, use the Firefox browser..