More padding bottom menu

https://github.com/FreshRSS/FreshRSS/issues/1479

p/themes/base-theme/template.css

@@ -345,7 +345,7 @@ a.btn {
 /*=== Tree */
 .tree {
 	margin: 0;
-	padding: 0;
+	padding: 0 0 15em 0;
 	list-style: none;
 	text-align: left;
 }