Why is there empty space on scroll?

Question

css

I can’t understand why there is an empty space at the footer when zooming in, tell me what is the problem?
Attached pictures 100% and 150%.

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Answer 1

it's not empty space. This is a picture pressed up and with the given parameters. you need to put it in the background (if it's not already in the background) and make it like

background-position: center center;
  background-size: cover;