Responsive independent page scrolling?

Question

css

On some news portal (unfortunately I don’t remember where exactly) I noticed an interesting solution.
There were several vertical columns on the page of different heights, but each above the height of the screen, on the right there was one standard scrollbar.
When scrolling down the page, they scroll normally at first, like a normal page.
When it reaches its end, the column with the smallest height pauses scrolling (waiting), and the longer one continues scrolling (as a result, the screen is never empty).
When the longest one is also over, they all go up together, showing the footer at the bottom of the page.
Help me remember where I saw this, or tell me how to implement this, please.

Answer 1

For example, the new Rambler , but this is done not through CSS, but JS by simply hanging .fixed_bottom { position: fixed; bottom: 0 } at the right moment.