v4: hardcoded white values (#fff) in both _cards.scss and mixins/background_variants.scss

Created by: bassjobsen

suggested solution:

in _variables.scss:

$body-bg:                    #fff !default;
$body-color:                 $gray-dark !default;
$body-color-inverse:    $gray-lightest !default;

then in _cards.scss:

// // Inverse text within a card for use with dark backgrounds //

.card-inverse {
  .card-header,
  .card-footer {
    border-bottom: .075rem solid rgba($body-color-inverse,.2);
  }
  .card-header,
  .card-footer,
  .card-title,
  .card-blockquote {
    color: #fff;
  }
  .card-link,
  .card-text,
  .card-blockquote > footer {
    color: rgba($body-color-inverse,.65);
  }
  .card-link {
    @include hover-focus {
      color: $body-color-inverse;
    }
  }
}

and in mixins/background-variants.scss:

// Contextual backgrounds

// [converter] $parent hack
@mixin bg-variant($parent, $color) {
  #{$parent} {
    color:$body-color-inverse;
    background-color: $color;
  }
  a#{$parent} {
    @include hover-focus {
      background-color: darken($color, 10%);
    }
  }
}