diff --git a/core/css/styles.css b/core/css/styles.css
index 15df58524772cada90df8aec27be4108ae6f4888..d3aec1568521647b265410c0e48f2a60ea7b52ff 100644
--- a/core/css/styles.css
+++ b/core/css/styles.css
@@ -266,19 +266,42 @@ fieldset.warning a { color:#b94a48 !important; font-weight:bold; }
 	-moz-box-shadow:0 0 7px #000; -webkit-box-shadow:0 0 7px #000; box-shadow:0 0 7px #000;
 	overflow:hidden; box-sizing:border-box; -moz-box-sizing:border-box;
 }
-#navigation:hover { overflow-y:auto; }
+#navigation:hover { overflow-y:auto; } /* show scrollbar only on hover */
 #navigation a span {
 	display:block;
 	text-decoration:none; font-size:10px; text-align:center;
 	color:#fff; text-shadow:#000 0 -1px 0;
-	-ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)"; filter:alpha(opacity=50); opacity:.5;
 	white-space:nowrap; overflow:hidden; text-overflow:ellipsis; /* ellipsize long app names */
 }
-	#navigation a:hover, #navigation a:focus { -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=80)"; filter:alpha(opacity=80); opacity:.8; }
-	#navigation a.active .icon, #navigation a.active span { -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=100)"; filter:alpha(opacity=100); opacity:1; }
+
+	/* icon opacity and hover effect */
+	#navigation a img,
+	#navigation a span {
+		/* 50% opacity when inactive */
+		-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";
+		filter: alpha(opacity=50);
+		opacity: .5;
+	}
+	#navigation a:hover img, #navigation a:focus img,
+	#navigation a:hover span, #navigation a:focus span {
+		/* 80% opacity when hovered or focused */
+		-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=80)";
+		filter: alpha(opacity=80);
+		opacity: .8;
+	}
+	#navigation a.active img,
+	#navigation a.active span {
+		 /* full opacity for the active app */
+		-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=100)";
+		filter: alpha(opacity=100);
+		opacity: 1;
+	}
+
+	/* positioning */
 	#navigation .icon {
-		display:block; width:32px; height:32px; margin:0 16px 0; padding:8px 0 4px; 	
-		-ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)"; filter:alpha(opacity=50); opacity:.5;
+		display:block;
+		width:32px; height:32px;
+		margin:0 16px 0; padding:8px 0 4px;
 	}
 	#navigation li:first-child a { padding-top:16px; }