Используй bootstrap scss _variables.scss
// Grid breakpoints
//
// Define the minimum dimensions at which your layout will change,
// adapting to different screen sizes, for use in media queries.
$grid-breakpoints: (
xs: 0,
sm: 576px,
md: 768px,
lg: 992px,
xl: 1200px
) !default;
@include _assert-ascending($grid-breakpoints, "$grid-breakpoints");
@include _assert-starts-at-zero($grid-breakpoints);
// Grid containers
//
// Define the maximum width of `.container` for different screen sizes.
$container-max-widths: (
sm: 540px,
md: 720px,
lg: 960px,
xl: 1300px
) !default;
@include _assert-ascending($container-max-widths, "$container-max-widths");
// Grid columns
//
// Set the number of columns and specify the width of the gutters.
$grid-columns: 12 !default;
$grid-gutter-width: 0 !default;