Constantly IE6 and/or IE7 behave as pain the the a** when you develop web-applications or websites.
But you can target your CSS and/or JavaScript for these browsers using just a few lines of simple code:
<!--[if lt IE 7]>
<link rel="stylesheet" type="text/css" media="screen" href="ie6.css" />
<![endif]-->
In this case we only check if the user's browser version is less than IE/, eg.