Default paragraphs in this page have yellow background. In any of the following test cases a blue background is set with a special (hack) rule. When the background is blue, the hack is applied.
Note: "All" == IE5+/Win, Op6+, Moz, Saf

IE6- (and IE7+ quirks) only
/*\*/ * html selector { property: value; } /**/

IE5.5- only
selector { property: value; p\roperty: normal-value; }

IE7 standard only
*:first-child+html selector { property: value; }

All except IE6- and IE7+ quirks
html>body selector { property: value; }

IE6+ quirks and IE5 (= all IE/Win quirks) only
* html selector { property /**/: value; }

All except IE6 standards
selector { property /**/: value; }

All except IE5.0
selector { property/**/: value; }

All except IE5.5
selector { property: /**/value; }