npm add bootstrap-borders-utilities
or
yarn add bootstrap-borders-utilities
Import the library in a custom bootstrap 4/5 theme base file
bootstrap.base.scss
or custom_theme.base.scss
// Custom theme base, with Bootstrap overrides.
// -----------------------------------------------------------------------------
@import "../../node_modules/bootstrap/scss/functions"; // Bootstrap functions.
@import "../../node_modules/bootstrap/scss/mixins"; // Bootstrap mixins.
@import "../../node_modules/bootstrap/scss/variables"; // Bootstrap variables.
@import "../variables"; // Custom theme variables.
@import "../mixins"; // Custom theme mixins.
@import "../../node_modules/bootstrap/scss/_utilities"; // Bootstrap utilities.
// -----------------------------------------------------------------------------
@import "../../node_modules/bootstrap-borders-utilities/utilities/scss/border-color-variants.scss";