docs/5.0/examples/headers/headers.css

.b-example-divider {
  height: 3rem;
  background-color: rgba(0, 0, 0, .1);
  border: solid rgba(0, 0, 0, .15);
  border-width: 1px 0;
  box-shadow: inset 0 .5em 1.5em rgba(0, 0, 0, .1), inset 0 .125em .5em rgba(0, 0, 0, .15);
}

.form-control-dark {
  color: #fff;
  background-color: var(--bs-dark);
  border-color: var(--bs-gray);
}
.form-control-dark:focus {
  color: #fff;
  background-color: var(--bs-dark);
  border-color: #fff;
  box-shadow: 0 0 0 .25rem rgba(255, 255, 255, .25);
}

.bi {
  vertical-align: -.125em;
  fill: currentColor;
}

.text-small {
  font-size: 85%;
}

.dropdown-toggle {
  outline: 0;
}