Code that hides rules in some browsers

How to hide CSS from certain browsers, using only CSS, preferably without hacks? There are probably a lot more. Do tell me :)

Internet Explorer 6

/* Ignored by IE 6 */
html>body {
 /* rules */
}

/* Ignored by IE 6 */
html > body {
 /* rules */
 /* Watch out; this is not ignored by IE 5! */
}

Internet Explorer 5

/* Ignored by IE 5 */
html>body {
 /* rules */
}

Internet Explorer 4

/* Ignored by IE4 */
@import "advanced.css";

/* Ignored by IE 4 */
@media all {
 /* rules */
}

Internet Explorer 5 (Mac)

/* Ignored by Mac IE 5 */
@media all {
 /* rules */
}

/* Ignored by Mac IE 5 \*/
 /* rules */
/* End ignoring */

Internet Explorer 4 (Mac)

/* Ignored by Mac IE 4 */
@media all {
 /* rules */
}

/* Ignored by Netscape 4 */
@import url('some.css');

Firefox

Opera 8

Opera 7

Opera 6

/* Ignored by Opera 6 */
head:first-child+body {
 /* rules */
}

Safari

/* Ignored by Safari */
@media all {
 @import url(some.css);
 /* rules */
}

Netscape 4

/* Ignored by Netscape 4 */
@import url(some.css);

/* Ignored by Netscape 4 */
@media all {
 /* rules */
}

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