Bootstrap/scss/_forms.scss

// scss-lint:disable QualifyingElement

//
// Textual form controls
//

.form-control {
  display: block;
  width: 100%;
  // // Make inputs at least the height of their button counterpart (base line-height + padding + border)
  // height: $input-height;
  padding: $input-padding-y $input-padding-x;
  font-size: $font-size-base;
  line-height: $input-line-height;
  color: $input-color;
  background-color: $input-bg;
  // Reset unusual Firefox-on-Android default style; see https://github.com/necolas/normalize.css/issues/214.
  background-image: none;
  background-clip: padding-box;
  border: $input-btn-border-width solid $input-border-color;

  // Note: This has no effect on <select>s in some browsers, due to the limited stylability of `<select>`s in CSS.
  @if $enable-rounded {
    // Manually use the if/else instead of the mixin to account for iOS override
    border-radius: $input-border-radius;
  } @else {
    // Otherwise undo the iOS default
    border-radius: 0;
  }

  @include box-shadow($input-box-shadow);
  @include transition($input-transition);

  // Unstyle the caret on `<select>`s in IE10+.
  &::-ms-expand {
    background-color: transparent;
    border: 0;
  }

  // Customize the `:focus` state to imitate native WebKit styles.
  @include form-control-focus();

  // Placeholder
  &::placeholder {
    color: $input-color-placeholder;
    // Override Firefox's unusual default opacity; see https://github.com/twbs/bootstrap/pull/11526.
    opacity: 1;
  }

  // Disabled and read-only inputs
  //
  // HTML5 says that controls under a fieldset > legend:first-child won't be
  // disabled if the fieldset is disabled. Due to implementation difficulty, we
  // don't honor that edge case; we style them as disabled anyway.
  &:disabled,
  &[readonly] {
    background-color: $input-bg-disabled;
    // iOS fix for unreadable disabled content; see https://github.com/twbs/bootstrap/issues/11655.
    opacity: 1;
  }

  &:disabled {
    cursor: $cursor-disabled;
  }
}

select.form-control {
  &:not([size]):not([multiple]) {
    $select-border-width: ($border-width * 2);
    height: calc(#{$input-height} + #{$select-border-width});
  }

  &:focus::-ms-value {
    // Suppress the nested default white text on blue background highlight given to
    // the selected option text when the (still closed) <select> receives focus
    // in IE and (under certain conditions) Edge, as it looks bad and cannot be made to
    // match the appearance of the native widget.
    // See https://github.com/twbs/bootstrap/issues/19398.
    color: $input-color;
    background-color: $input-bg;
  }
}

// Make file inputs better match text inputs by forcing them to new lines.
.form-control-file,
.form-control-range {
  display: block;
}


//
// Labels
//

// For use with horizontal and inline forms, when you need the label text to
// align with the form controls.
.col-form-label {
  padding-top: calc(#{$input-padding-y} - #{$input-btn-border-width} * 2);
  padding-bottom: calc(#{$input-padding-y} - #{$input-btn-border-width} * 2);
  margin-bottom: 0; // Override the `<label>` default
}

.col-form-label-lg {
  padding-top: calc(#{$input-padding-y-lg} - #{$input-btn-border-width} * 2);
  padding-bottom: calc(#{$input-padding-y-lg} - #{$input-btn-border-width} * 2);
  font-size: $font-size-lg;
}

.col-form-label-sm {
  padding-top: calc(#{$input-padding-y-sm} - #{$input-btn-border-width} * 2);
  padding-bottom: calc(#{$input-padding-y-sm} - #{$input-btn-border-width} * 2);
  font-size: $font-size-sm;
}


//
// Legends
//

// For use with horizontal and inline forms, when you need the legend text to
// be the same size as regular labels, and to align with the form controls.
.col-form-legend {
  padding-top: $input-padding-y;
  padding-bottom: $input-padding-y;
  margin-bottom: 0;
  font-size: $font-size-base;
}


// Static form control text
//
// Apply class to an element to make any string of text align with labels in a
// horizontal form layout.

.form-control-static {
  padding-top: $input-padding-y;
  padding-bottom: $input-padding-y;
  margin-bottom: 0; // match inputs if this class comes on inputs with default margins
  line-height: $input-line-height;
  border: solid transparent;
  border-width: 1px 0;

  &.form-control-sm,
  &.form-control-lg {
    padding-right: 0;
    padding-left: 0;
  }
}


// Form control sizing
//
// Build on `.form-control` with modifier classes to decrease or increase the
// height and font-size of form controls.
//
// The `.form-group-* form-control` variations are sadly duplicated to avoid the
// issue documented in https://github.com/twbs/bootstrap/issues/15074.

.form-control-sm {
  padding: $input-padding-y-sm $input-padding-x-sm;
  font-size: $font-size-sm;
  @include border-radius($input-border-radius-sm);
}

select.form-control-sm {
  &:not([size]):not([multiple]) {
    height: $input-height-sm;
  }
}

.form-control-lg {
  padding: $input-padding-y-lg $input-padding-x-lg;
  font-size: $font-size-lg;
  @include border-radius($input-border-radius-lg);
}

select.form-control-lg {
  &:not([size]):not([multiple]) {
    height: $input-height-lg;
  }
}


// Form groups
//
// Designed to help with the organization and spacing of vertical forms. For
// horizontal forms, use the predefined grid classes.

.form-group {
  margin-bottom: $form-group-margin-bottom;
}

.form-text {
  display: block;
  margin-top: $form-text-margin-top;
}


// Checkboxes and radios
//
// Indent the labels to position radios/checkboxes as hanging controls.

.form-check {
  position: relative;
  display: block;
  margin-bottom: $form-check-margin-bottom;

  &.disabled {
    .form-check-label {
      color: $text-muted;
      cursor: $cursor-disabled;
    }
  }
}

.form-check-label {
  padding-left: $form-check-input-gutter;
  margin-bottom: 0; // Override default `<label>` bottom margin
  cursor: pointer;
}

.form-check-input {
  position: absolute;
  margin-top: $form-check-input-margin-y;
  margin-left: -$form-check-input-gutter;

  &:only-child {
    position: static;
  }
}

// Radios and checkboxes on same line
.form-check-inline {
  display: inline-block;

  .form-check-label {
    vertical-align: middle;
  }

  + .form-check-inline {
    margin-left: $form-check-inline-margin-x;
  }
}


// Form control feedback states
//
// Apply contextual and semantic states to individual form controls.

.form-control-feedback {
  margin-top: $form-feedback-margin-top;
}

.form-control-success,
.form-control-warning,
.form-control-danger {
  padding-right: ($input-padding-x * 3);
  background-repeat: no-repeat;
  background-position: center right ($input-height / 4);
  background-size: ($input-height / 2) ($input-height / 2);
}

// Form validation states
.has-success {
  @include form-control-validation($brand-success);

  .form-control-success {
    background-image: $form-icon-success;
  }
}

.has-warning {
  @include form-control-validation($brand-warning);

  .form-control-warning {
    background-image: $form-icon-warning;
  }
}

.has-danger {
  @include form-control-validation($brand-danger);

  .form-control-danger {
    background-image: $form-icon-danger;
  }
}


// Inline forms
//
// Make forms appear inline(-block) by adding the `.form-inline` class. Inline
// forms begin stacked on extra small (mobile) devices and then go inline when
// viewports reach <768px.
//
// Requires wrapping inputs and labels with `.form-group` for proper display of
// default HTML form controls and our custom form controls (e.g., input groups).

.form-inline {
  display: flex;
  flex-flow: row wrap;

  // Because we use flex, the initial sizing of checkboxes is collapsed and
  // doesn't occupy the full-width (which is what we want for xs grid tier),
  // so we force that here.
  .form-check {
    width: 100%;
  }

  // Kick in the inline
  @include media-breakpoint-up(sm) {
    label {
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 0;
    }

    // Inline-block all the things for "inline"
    .form-group {
      display: flex;
      flex: 0 0 auto;
      flex-flow: row wrap;
      align-items: center;
      margin-bottom: 0;
    }

    // Allow folks to *not* use `.form-group`
    .form-control {
      display: inline-block;
      width: auto; // Prevent labels from stacking above inputs in `.form-group`
      vertical-align: middle;
    }

    // Make static controls behave like regular ones
    .form-control-static {
      display: inline-block;
    }

    .input-group {
      width: auto;
    }

    .form-control-label {
      margin-bottom: 0;
      vertical-align: middle;
    }

    // Remove default margin on radios/checkboxes that were used for stacking, and
    // then undo the floating of radios and checkboxes to match.
    .form-check {
      display: flex;
      align-items: center;
      justify-content: center;
      width: auto;
      margin-top: 0;
      margin-bottom: 0;
    }
    .form-check-label {
      padding-left: 0;
    }
    .form-check-input {
      position: relative;
      margin-left: 0;
    }

    // Custom form controls
    .custom-control {
      display: flex;
      align-items: center;
      justify-content: center;
      padding-left: 0;
    }
    .custom-control-indicator {
      position: static;
      display: inline-block;
      margin-right: .25rem; // Flexbox alignment means we lose our HTML space here, so we compensate.
      vertical-align: text-bottom;
    }

    // Re-override the feedback icon.
    .has-feedback .form-control-feedback {
      top: 0;
    }
  }
}