Who can check the layout / assembly of a landing page on flexbox / do a code review?

Question

css

Colleagues, hello!
Made a landing page on flexbox. I ask you (who have the time and desire) to do a code review.
Tell me what you did well, what you didn't do well, and what you did really badly. I welcome constructive criticism.
Also, please see the .timeline block: there is a thin gray line through the round photos. She has a problem. I make it a pseudo-element - but when scaling it moves to the side. Most likely it should be done through absolute
positioning, but I have it on the display: flex block. I would be grateful for advice on how to correctly lay out this strip.
Repository link:
https://github.com/DmitryBecker/golden_flexbox_gulp
Thanks.