alt131 - 9:29 am on Sep 22, 2011 (gmt 0)

Hi Efe, thanks for posting the code - is that the code that is now working - or the earlier code that wasn't working as desired? The reason I ask is because I'd like to explore margin collapsing, and "working" code won't expose the issue.

So the function of !important is overriding default stylesheet settings then. Doesn't that apply automaticly when you define your own values?

Not quite - the cascade assigns a "weight" to rules, and !important gives a rule more "weight", so usually it will be applied unless your own rules ahve a greater weight or specificity.

I've seen it in use before but never understood it. Isn't that the same function of reseting css (http://meyerweb.com/eric/tools/css/reset/?

Again, not quite. A reset will only "reset" rules that have a lesser weight. Useful reading on this is the cascade (section 6.4) [w3.org]. A reset relies on having greater weight, usually because it is applied last. However, !important will mostly retain greater weight, so won't be over-ridden.

I think this is an interesting question (thanks), and for me the key to understanding is recognising they are different things: !important affects the weight of a rule, while the idea behind a reset is that it will over-ride earlier rules because of it's place in the cascade.

!important is very powerful, but be cautious if using it - it can be difficult to over-ride and the most common technique is to start using very specific selectors. But that creates very specific code, and that can create real maintenance issues.