How to scroll to the block below?

Question

css

Initially, the site opens from the header, how to make it so that when the user turns the wheel, he immediately scrolls down to the next section, and then he manually scrolls?

While I was writing the question, I wrote the solution myself, although it seems to me a little "dirty", maybe someone knows how to write it cleaner or in pure JS - I will be grateful.

Solution for now - https://codepen.io/anon/pen/RQQgee