[Outlined labels mixin for Bootstrap 4.*]

label-outline-variant.scss

@mixin label-outline-variant(
    $color, 
    $color-hover: color-yiq($color), 
    $active-background: $color, 
    $active-border: $color
) {
    color: $color;
    border-color: $color;

    &:hover {
        color: $color-hover;
        background-color: $active-background;
        border-color: $active-border;
    }

    &:focus,
    &.focus {
        box-shadow: 0 0 0 $btn-focus-width rgba($color, .5);
    }

    &:disabled,
    &.disabled {
        color: $color;
        background-color: transparent;
    }

    &:not(:disabled):not(.disabled):active,
    &:not(:disabled):not(.disabled).active,
    .show > &.dropdown-toggle {
        color: color-yiq($active-background);
        background-color: $active-background;
        border-color: $active-border;

        &:focus {
            @if $enable-shadows and $btn-active-box-shadow != none {
                box-shadow: $btn-active-box-shadow, 0 0 0 $btn-focus-width rgba($color, .5);
            } @else {
                box-shadow: 0 0 0 $btn-focus-width rgba($color, .5);
            }
        }
    }
}
@each $color, $value in $theme-colors {
    .label-outline-#{$color} {
        @include label-outline-variant($value);
    }
}