With CMSimple 3.2.3 or higher you can style various areas of the main menu and each menu item individually. This is possible, because the plugin function defines its own CSS classes for each menu item, for example from the page title.
You also can insert special h1 pages that are visible as intermediate headings without links in the vertical navigation menu, and split the navigation menu this way.
For demonstration of the new menu options, an own Documentation- and Demowebsite of the new design options is available: