increase gap between buttons in titlebars

src/App.scss

@@ -566,7 +566,7 @@ main-router {
     min-height: 0;
     box-sizing: border-box;
     margin: 0;
-    margin-left: .25em;
+    margin-left: .5em;
     min-width: 1px;
     align-self: stretch;
   }