How to split top bar menu

I’m trying to create a divided/split menu similar to https://www.123ink.ca/ where there’s a menu on the left side as well are the right side at the top bar. I thought that the easiest way to do this would be to label each menu item with a CSS class then float them to the respective sides. However, I don’t think this theme allows for that because it doesn’t seem to do anything lol. Does anybody have any ideas on how to help split the top bar menu?

Here is the code that I inserted as additional CSS:

I labeled my menu items:
WP Dashboard –> Appearance –> Menus
Screen Options –> CSS Classes

Then labeled my items with the CSS Class either:
menu-item-float-left
menu-item-float-right

Then inserted additional CSS as:
WP Dashboard –> Appearance –> Customize –> Additional CSS

@media (min-width: 769px) {
.menu-item-float-left {
float: left !important;
}
}

and then I did the same for the right side but to no avail.
Please send help.

How to right-align and left-align menu items on the same line. OceanWP Theme.