for #main-content
I don't want to give any fix height because content can be long and short but if content is short then it should take minimum height 500px.
i need compatibility in all browser.
Is thery any w3c valid and cross browser way without using !important because i read !important should not be used
In conclusion, don’t use the
!important declaration unless you’ve
tried everything else first, and keep
in mind any drawbacks. If you do use
it, it would probably make sense, if
possible, to put a comment in your CSS
next to any styles that are being
overridden, to ensure better code
maintainability.
I tried to cover everything
significant in relation to use of the
!important declaration, so please
offer comments if you think there’s
anything I’ve missed, or if I’ve
misstated anything, and I’ll be happy
to make any needed corrections.
http://www.impressivewebs.com/everything-you-need-to-know-about-the-important-css-declaration/