How to connect bootstrap with sass?

Question

Sass

There is a starter template from kodriver https://github.com/coderiver/gulp
I want to add a bootstrap grid there. I download the source, transfer the kernel to the project folder, import the bootstrap.sccs file, the files it needs are nearby, everything is connected normally.
I create the .container>.row ... markup - for some reason the container on the big screen is not 1170 pixels, but 750 (720 breakpoint + 30 gutter). The inspector nods at the grid.scss file where there are requests like this:

.container {
  @include container-fixed;

  @media (min-width: $screen-sm-min) {
    width: $container-sm;
  }
  @media (min-width: $screen-md-min) {
    width: $container-md;
  }
  @media (min-width: $screen-lg-min) {
    width: $container-lg;
  }
}

For some reason, $container-sm works, not lg.
I take bootstrap 4.0 - the same thing, only there the lower breakpoint is 540 and my container also becomes 540. Some kind of mobile-fest turns out.
Question: how do you connect this bootstrap??