Unknown CSS, mobile/tablet optimization?

I recently got back into working on my site code after a 3 year hiatus. I am trying to understand the origins of the CSS code here– whether it’s from theme updates (Flatsome w/ child), plugins, GUI customizations, or my own manual adding. I’ve used GPT for explaining it, and it appears to be for mobile/tablet optimization and responsivity.

I don’t remember adding any of it since I never really worried about mobile or tablet responsivity – it was something I was going to do in the future, but as you can see, there are multiple blocks. Perhaps I read a thread somewhere about mobile responsivity, and I was persuaded into adding it to my custom CSS. That is my best guess, but I am hoping someone with much better expertise can give me their best guess.

Just hoping to clean things up so I don’t get too left behind on the code for my own site!

A moderator (t-p) over at WP forums thinks it’s likely from my theme, and directed me to ask here. I think it makes sense, but at the same time, I would think this CSS wouldn’t be in “additional CSS” but instead in a more core file somewhere. Thank you!

You don’t have much option to extend the support and ask the questions to the item author as this is beyond of help for someone else, for the item author, you will need to have active support period.