@each $color, $value in $theme-colors-alt {
  @include bg-variant(".bg-#{$color}", $value, true);
}

@if $enable-gradients {
  @each $color, $value in $theme-colors-alt {
    @include bg-gradient-variant(".bg-gradient-#{$color}", $value, true);
  }
}

.bg-white {
  background-color: $white-alt !important;
}

.bg-black {  // ADDED THIS ONE!
  background-color: $black-alt !important;
}