Dynamically change background and text color of a menu item

You'd have to write the complex logic you require prior to displaying the menu and then filter visual elements to CSS from that result.

It's easier to not to mess with that, and instead leave the menus alone and modify the redirect pages managed by rules from the originating pages. These are also more likely to achieve the marketing prowess you're seeking instead of faded menues and "cannot click links"

Many thanks for replying and your advice.