Upstream commit, that is fixing warnings on modern gtk3
https://github.com/conformal/xombrero/commit/aa57b80c

--- xombrero.css.orig	2015-02-17 16:11:49 UTC
+++ xombrero.css
@@ -25,8 +25,8 @@
 
 * {
 	border-width: 1px;
-	padding: 1;
-	margin: 1;
+	padding: 1px;
+	margin: 1px;
 	-GtkScrolledWindow-scrollbar-spacing: 1;
 	-GtkWidget-line-width: 1;
 }