Need to target IE browsers? Here is a quick hack that doesn’t require conditional comments (note that your CSS will therefore not pass auto-validation, which is fine if you are aware of why it doesn’t).
The code below will change the background-color of divs depending on what browser the user is viewing the web page under. Since * cascades down to IE7 and below, we use _ after that declaration so that IE6 (and below) has a different background color from IE7.
background-color: #999; /* all browsers */
*background-color: #ccc; /* add a * before the property – IE7 and below */
_background-color: #000; /* add a _ before the property – IE6 and below */