[css] How to override !important?

I would like to add an answer to this that hasn't been mentioned, as I have tried all of the above to no avail. My specific situation is that I am using semantic-ui, which has built in !important attributes on elements (extremely annoying). I tried everything to override it, only in the end did one thing work (using jquery). It is as follows:

$('.active').css('cssText', 'border-radius: 0px !important');