AdminLTE/scss/dark/bootstrap/mixins/_forms.scss

@mixin form-validation-state-alt(
  $state,
  $color,
  $icon,
  $tooltip-color: color-contrast($color, $color-contrast-dark-alt, $color-contrast-light-alt, $min-contrast-ratio-alt),
  $tooltip-bg-color: rgba($color, $form-feedback-tooltip-opacity-alt),
  $focus-box-shadow: 0 0 $input-btn-focus-blur-alt $input-focus-width rgba($color, $input-btn-focus-color-opacity-alt)
) {
  .#{$state}-feedback {
    color: $color;
  }

  .#{$state}-tooltip {
    color: $tooltip-color;
    background-color: $tooltip-bg-color;
  }

  .form-control {
    @include form-validation-state-selector($state) {
      border-color: $color;

      @if $enable-validation-icons {
        background-image: escape-svg($icon);
      }

      &:focus {
        border-color: $color;
        box-shadow: $focus-box-shadow;
      }
    }
  }

  .form-select {
    @include form-validation-state-selector($state) {
      border-color: $color;

      @if $enable-validation-icons {
        &:not([multiple]):not([size]),
        &:not([multiple])[size="1"] {
          background-image: escape-svg($form-select-indicator-alt), escape-svg($icon);
        }

        &[multiple],
        &[size]:not([size="1"]) {
          background-image: escape-svg($icon);
        }
      }

      &:focus {
        border-color: $color;
        box-shadow: $focus-box-shadow;
      }
    }
  }

  .form-check-input {
    @include form-validation-state-selector($state) {
      border-color: $color;

      &:checked {
        background-color: $color;
      }

      &:focus {
        box-shadow: $focus-box-shadow;
      }

      ~ .form-check-label {
        color: $color;
      }
    }
  }
}