Responsive homepage with accessibility in mind

Hello, this is my first project on this platform!

For a better user experience I've added some basic ARIA attributes (still learning) and defined a design based focus outline for keyboard users. I've also followed the BEM naming convention, but I'm not quite sure if I did it right.

So, my questions are:

• Am I overdoing it with the BEM class names? If yes, how can I do it better? I read many articles about it over and over, and I'm still not sure when it's appropriate to use it.
• Would you suggest some improvements regarding web accessibility or anything else?

I'm looking forward to your responses!