How to make a menu appear when scrolling down?

Question

css

Hello, tell me how to make a vertical menu appear when scrolling down with the active class, which changes when you switch to another section,
An example is on the site https://www.marco.fyi

Answer 1

You track the scroll event and, for example, if you scroll more than 500, add the block class

(window.pageYOffset > 500){
      navigation.classList.add('block')

in order to keep track of which section you are in, there is a poke