Border

<div className="border"></div>
<div className="border-top"></div>
<div className="border-right"></div>
<div className="border-bottom"></div>
<div className="border-left"></div>

<div className="border-0"></div>
<div className="border-top-0"></div>
<div className="border-right-0"></div>
<div className="border-bottom-0"></div>
<div className="border-left-0"></div>

<div className="border border-primary"></div>
<div className="border border-secondary"></div>
<div className="border border-success"></div>
<div className="border border-info"></div>
<div className="border border-warning"></div>
<div className="border border-danger"></div>
<div className="border border-dark"></div>
<div className="border border-light"></div>

$border-theme-colors: (
  'primary': (
    border-color: $primary !important,
  ),
  '%b-tertiary': (
    border-color: green !important,
  ),
  '.b-tertiary': (
    extend: '%border-tertiary',
  ),
  '.b-quaternary': (
    extend: '%border-tertiary',
  ),
);

.border-primary {
  border-color: #0b5fff !important;
}

.b-tertiary,
.b-quaternary {
  border-color: green !important;
}

<div className="rounded"></div>
<div className="rounded-top"></div>
<div className="rounded-right"></div>
<div className="rounded-bottom"></div>
<div className="rounded-left"></div>
<div className="rounded-circle"></div>
<div className="rounded-pill"></div>
<div className="rounded-0"></div>

<div className="rounded-sm"></div>
<div className="rounded-lg"></div>