we need a link if we are to help you. a blind advice could do more harm.
that said, you can target ie the way you see fit. the debate of CC vs HACKS has less to do with how you want the things done, and more with the actual path you take to achieve your goal. they both get you there.
if all you want is to make darker colour for ie, there are ie hacks for css selectors and rules, allowing you to target ie6 or ie7. alternatively, you could use CC to point to a css file having these selectors and rules, w/o hacks this time.
if you rely on css3 only, you also need to know not all browsers support it, and those supporting it may only support bits and pieces of it, and css3 is not for production use yet.
the problem is there are many ways and you have to find the right way