Index: wp-admin/css/wp-admin.css
===================================================================
--- wp-admin/css/wp-admin.css	(revision 24701)
+++ wp-admin/css/wp-admin.css	(working copy)
@@ -3522,14 +3522,13 @@
 
 .revisions-tickmarks {
 	position: relative;
-	margin: 0 auto 0;
+	margin: 0 auto;
 	height: 0.8em;
 	z-index: 2;
 	top: 7px;
 	width: 70%;
 	-moz-box-sizing: border-box;
 	-webkit-box-sizing: border-box;
-	-ms-box-sizing: border-box; /* ie8 only */
 	box-sizing: border-box;
 }
 
@@ -3542,11 +3541,10 @@
 	border-width: 0 0 0 1px;
 	-moz-box-sizing: border-box;
 	-webkit-box-sizing: border-box;
-	-ms-box-sizing: border-box; /* ie8 only */
 	box-sizing: border-box;
 }
 
-.revisions-tickmarks > div:first-of-type {
+.revisions-tickmarks > div:first-child {
 	border-left-width: 0;
 }
 
@@ -3559,6 +3557,7 @@
 	text-align: center;
 	vertical-align: middle;
 	opacity: 0;
+	filter: alpha(opacity=0);
 	margin: 0 auto;
 	width: 100%;
 	height: 32px;
@@ -3573,6 +3572,7 @@
 
 .revisions.loading .loading-indicator {
 	opacity: 1;
+	filter: alpha(opacity=100);
 }
 
 .revisions .diff {
@@ -3584,7 +3584,8 @@
 }
 
 .revisions.loading .diff {
-	opacity: 0.5;
+	opacity: .5;
+	filter: alpha(opacity=50);
 }
 
 .revisions-meta {
@@ -3612,7 +3613,7 @@
 
 .wp-slider {
 	width: 70%;
-	margin: 0 auto 0;
+	margin: 0 auto;
 	top: -3px;
 }