Website from mockup (pet-project)

Hey, folks!:evergreen_tree:

I made my first responsive website:grin:

I didn’t use bootstrap or jquery frameworks, or pure JS. It’s consist with only pure semantic HTML(5) and CSS(3). I need some feedback. The mockup was only for desktop version. That why this website is desktop-first.
Oh! It’s also has some cross-browsing capabilities…
I’ll really happy to have a feedback from the comunity and to get a lot’s of criticisms.