Connect DIV with line on hover over for responsive webpage

Hello guys,

This community has been most helpful over the years.

I hope that someone could help me upgrade a webpage that I’ve stated as a fun project some time ago but now I see value in upgrading to an actual webpage.

There are a couple of things in particular that I would appreciate if someone could help me with:
a) Advise on what would be the best approach to make it responsive (right now I use flex with EM margins set for the elements)
b) Create a hover over animation which shows a connecting line between 2 images/divs and be responsive.

Read-Only link:
https://preview.webflow.com/preview/the-i-mind-website-2020?utm_medium=preview_link&utm_source=designer&utm_content=the-i-mind-website-2020&preview=b9b3355ae49dd102a17a5fda6b46fa2e&workflow=preview