I recently was doing some css development, and ran into a right little head scratcher
I was having some positioning issues with a background image, and so i wanted to specify that in Internet Explorer, you use one image, in any other browser you use another
In my Css i had seperated it out into using a header element and a header_ie element
My first port of call was http://www.conditional-css.com/usage
Getting the [if IE] working was perfect, however getting the counter of it was more difficult
The suggested method is below
[if ! Opera] - Used if the browser is not Opera (for example)
However this did not work for me at all. After some poking around i found the answer, but for the life of me i cannot find the site again.
The below code works fine, note the additional exclamation marks
<!--[if !IE]><!--><div id="header"><!--<![endif]-->
<!--[if IE]><div id="header_ie"><![endif]-->
