Mozilla Firefox Hacking

We always keep blaming IE for wrong rendering of the XHTML and CSS and keep finding the workaround of that only.But sometime (like is my recent project)everything was working fine but Mozilla was stuck, so I needed a workaround so that my particular style should be visible only in mozilla and after doing research on Google I got the Hack for Mozilla:-

@-moz-document url-prefix(){
.wrapper{
width:500px;
padding:5px;}}


// This will be visible on all browsers but not in Firefox as we have applied
hack for that.
.wrapper{
width:600px;
padding:5px;}}

Thanks,