Default theme: Fix hr element theming in IE8+

themes/default/style.css

@@ -215,6 +215,7 @@ img { max-width: 100%; }
 hr {
     border: 0.15em solid #f5f5f5;
     border-radius: 0.3em;
+    background: #f5f5f5;
 }
 
 abbr { text-decoration: underline dotted; }