foundation-sites/scss/forms/_error.scss

// Foundation for Sites by ZURB
// foundation.zurb.com
// Licensed under MIT Open Source

////
/// @group abide
////

/// Sets if error styles should be added to inputs.
/// @type Boolean
$abide-inputs: true !default;

/// Sets if error styles should be added to labels.
/// @type Boolean
$abide-labels: true !default;

/// Background color to use for invalid text inputs.
/// @type Color
$input-background-invalid: get-color(alert) !default;

/// Color to use for labels of invalid inputs.
/// @type Color
$form-label-color-invalid: get-color(alert) !default;

/// Default font color for form error text.
/// @type Color
$input-error-color: get-color(alert) !default;

/// Default font size for form error text.
/// @type Number
$input-error-font-size: rem-calc(12) !default;

/// Default font weight for form error text.
/// @type Keyword
$input-error-font-weight: $global-weight-bold !default;

/// Styles the background and border of an input field to have an error state.
///
/// @param {Color} $background [$alert-color] - Color to use for the background and border.
/// @param {Number} $background-lighten [10%] - Lightness level of the background color.
@mixin form-input-error(
  $background: $input-background-invalid,
  $background-lighten: 10%
) {
  &:not(:focus) {
    border-color: $background;
    background-color: mix($background, $white, $background-lighten);
    &::placeholder {
      color: $background;
    }
  }
}

/// Adds error styles to a form element, using the values in the settings file.
@mixin form-error {
  display: none;
  margin-top: $form-spacing * -0.5;
  margin-bottom: $form-spacing;

  font-size: $input-error-font-size;
  font-weight: $input-error-font-weight;
  color: $input-error-color;
}

@mixin foundation-form-error {
  @if $abide-inputs {
    // Error class for invalid inputs
    .is-invalid-input {
      @include form-input-error;
    }
  }

  @if $abide-labels {
    // Error class for labels of invalid outputs
    .is-invalid-label {
      color: $form-label-color-invalid;
    }
  }

  // Form error element
  .form-error {
    @include form-error;

    &.is-visible {
      display: block;
    }
  }
}