If you use Divi's single page navigation layout, you may notice some odd behavior from your sub-menus.

For instance, the following example shows the menu after clicking onto the "hours" section of the "Visit Us" page. In this case all of the links are highlighted (as they are all links to the current page), except for the "hours" link which has been marked as visited and is now shown in black. This gives almost the opposite effect of what many people would expect:

To fix this, I added the following CSS:

#top-menu li.current-menu-item > a { color: black !important; }
#top-menu li.current-menu-item > a:hover { color: #2ea3f2 !important; }

This makes all the links default to black, except when hovered on. It's not perfect (in particular, it may be desirable to highlight the currently active page), but it is an improvement on the above: