Why isn't the ::selection pseudo-element applied to the body?

Question

css

With div and p everything works, but main and so on. No

Answer 1

Why isn't the ::selection pseudo-element applied to the body?

This is not true.
It applies to body body::selection{}and works. But it is not inherited.

https://jsfiddle.net/og2d4mwk/
If you need to apply to all elements, then write like this

::selection {
  background: #f00;
}

or specify specific tags/classes.
And don't forget the autoprefixer.

Answer 2

Can be applied to the entire document

::selection {
  color: red;
  background: yellow;
}