CSS Override
Design and Skin Customization
You don't need to use !important (or shouldn't have to except as a last resort.).
My guess is that the caches need to be cleared:
yoursite.com/core/cache_reset
If it absolutely wont change and you are talking about a module provided template (because you should have total control over your skins templates) then one option is to duplicate that modules annoying file in your skin and give it another class.
ie:
/modules/jrAudio/item_details.tpl
override it by copying it to:
/skins/xxYourSkin/jrAudio_item_details.tpl
and then its yours. Your skin version will trump the module version. (this seams a bit excessive for just a css over-ride though, check the CSS is actually coming out in the code.)