Intro-section-with-dropdown-navigation-main CSS JS FLEX

Hello. This is my second project using JS. I'm learning how to work with it, so any comments and advice are welcome. To be honest - they helped me a little with the structure of the js code, in particular, so that everything worked well when clicking outside the elements. The structure of the event listener is still quite cumbersome for me and I am looking for a more elegant solution.