AdminLTE/build/scss/mixins/_backgrounds.scss

//
// Mixins: Backgrounds
//

// Background Variant
@mixin background-variant($name, $color) {
  .bg-#{$name} {
    background-color: #{$color} !important;

    &,
    > a {
      color: color-yiq($color) !important;
    }

    &.btn {
      &:hover {
        border-color: darken($color, 10%);
        color: darken(color-yiq($color), 7.5%);
      }

      &:not(:disabled):not(.disabled):active,
      &:not(:disabled):not(.disabled).active,
      &:active,
      &.active {
        background-color: darken($color, 10%) !important;
        border-color: darken($color, 12.5%);
        color: color-yiq(darken($color, 10%));
      }
    }
  }
}

// Background Gradient Variant
@mixin background-gradient-variant($name, $color) {
  .bg-gradient-#{$name} {
    // Ignore warning for Bootstrap 4 deprecation
    // TODO: remove bg-gradient-variant dependencies
    @include bg-gradient-variant("&", $color, true);
    color: color-yiq($color);

    &.btn {
      &.disabled,
      &:disabled,
      &:not(:disabled):not(.disabled):active,
      &:not(:disabled):not(.disabled).active,
      .show > &.dropdown-toggle {
        background-image: none !important;
      }

      &:hover {
        // Ignore warning for Bootstrap 4 deprecation
        // TODO: remove bg-gradient-variant dependencies
        @include bg-gradient-variant("&", darken($color, 7.5%), true);
        border-color: darken($color, 10%);
        color: darken(color-yiq($color), 7.5%);
      }

      &:not(:disabled):not(.disabled):active,
      &:not(:disabled):not(.disabled).active,
      &:active,
      &.active {
        // Ignore warning for Bootstrap 4 deprecation
        // TODO: remove bg-gradient-variant dependencies
        @include bg-gradient-variant("&", darken($color, 10%), true);
        border-color: darken($color, 12.5%);
        color: color-yiq(darken($color, 10%));
      }
    }
  }
}