Arbitrary spacing between elements, how to remove?

Question

css

Why is there an indent after the next button, and what is this indent?

Answer 1

I did not find a solution, and I did not understand what kind of margin it is that cannot be removed.
Remade through divs and justify content.

Answer 2

The block has the mt-5 class added.
As I understand it, this is the class of the Bootstrap library.
If you look in the inspector, you will see:

.mt-5 {
  margin-top: 3rem!important;
}