Added border-bottom utility class

css/general/layout.css

@@ -49,6 +49,10 @@ div.grid-3columns-auto {
 	grid-column-gap: 1em;
 }
 
+.border-bottom {
+	border-bottom: 1px solid;
+}
+
 .margin-top {
 	margin-top: 1em;
 }