I created a website that has different navigation menus. In 2 menus, I use the same HTML class element.
I have a .css file that styles that class element in 1 menu.
I'll just add that typically when there are multiple menus you might have them wrapped in a different structure. Take for instance:
Some different code
You can easily target these:
.mainnav>.classone {}
.wrapper>.classone {}
Or if the parent html has a class:
Some code
Some code
.ancestor1 .classname {}
.ancestor2 .classname {}
Obviously this depends on where in the html they might be.