Hi Charlie,
You can apply your own menu setting by using the "CustomCSS" property of the menu control. Attached is the sample in which the Custom stylesheet is added to the menu.
http://websamples.syncfusion.com/samples/Tools.Web/5.1.0.51/F62510/Menu_Forum62510/main.htmTry this and Let us know if it helps.
Thanks for using Syncfusion products.
Regards,
Gokulkumar B