Triggered Menus in Builder and CSS issues

Hey there.
I am trying to get a mobile "burger" menu set up in Builder.
When I load the page the menu is not visible. Do I need to set up some kind of custom CSS to show a burger menu? Can you instruct me on getting this set up?

Also, the styling of the template/layout is not the same as the actual result when you view the page, is this a technical difficulty? do you have recommended server settings for best performance with builder? (example: text is grey in builder but outputs white when viewing page)