add arrows to indicate link directionality
diff --git a/web/ons-demo/css/skin.default.css b/web/ons-demo/css/skin.default.css
index 5063039..3a63ae2 100644
--- a/web/ons-demo/css/skin.default.css
+++ b/web/ons-demo/css/skin.default.css
@@ -43,6 +43,11 @@
 	border: 1px solid white;
 }
 
+#arrow {
+	stroke: none;
+	fill: rgba(255, 255, 255, .25);
+}
+
 .header {
 	height: 50px;
 }
@@ -92,7 +97,7 @@
 
 path {
 	stroke: rgba(255, 255, 255, .25);
-	stroke-width: 1px;
+	stroke-width: 1.5px;
 }
 
 .aggregation {