Bootstrap/scss/_forms.scss

//
// Forms
// --------------------------------------------------


//
// 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-base;
  padding: $padding-base-vertical $padding-base-horizontal;
  font-size: $font-size-base;
  line-height: $line-height-base;
  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;
  border: 1px solid $input-border;
   // Note: This has no effect on <select>s in some browsers, due to the limited stylability of `<select>`s in CSS.
  @include border-radius($input-border-radius);
  @include box-shadow(inset 0 1px 1px rgba(0,0,0,.075));
  transition: border-color ease-in-out .15s, box-shadow ease-in-out .15s;

  // Make inputs at least the height of their button counterpart (base line-height + padding + border).
  // Only apply the height to textual inputs and some selcts.
  &:not(textarea),
  &:not(select[size]),
  &:not(select[multiple]) {
    height: $input-height-base;
  }

  // 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],
  fieldset[disabled] & {
    background-color: $input-bg-disabled;
    // iOS fix for unreadable disabled content; see https://github.com/twbs/bootstrap/issues/11655.
    opacity: 1;
  }

  &[disabled],
  fieldset[disabled] & {
    cursor: $cursor-disabled;
  }
}


// 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.
.form-control-label {
  padding: ($padding-base-vertical + $border-width) $padding-base-horizontal;
  margin-bottom: 0; // Override the `<label>` default
}


// Todo: clear this up

// Special styles for iOS temporal inputs
//
// In Mobile Safari, setting `display: block` on temporal inputs causes the
// text within the input to become vertically misaligned. As a workaround, we
// set a pixel line-height that matches the given height of the input, but only
// for Safari. See https://bugs.webkit.org/show_bug.cgi?id=139848

// @media screen and (-webkit-min-device-pixel-ratio: 0) {
//   input[type="date"],
//   input[type="time"],
//   input[type="datetime-local"],
//   input[type="month"] {
//     line-height: $input-height-base;

//     &.input-sm,
//     .input-group-sm & {
//       line-height: $input-height-sm;
//     }

//     &.input-lg,
//     .input-group-lg & {
//       line-height: $input-height-lg;
//     }
//   }
// }


// 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 {
  min-height: $input-height-base;
  // Size it appropriately next to real form controls
  padding-top: ($padding-base-vertical + $border-width);
  padding-bottom: ($padding-base-vertical + $border-width);
  // Remove default margin from `p`
  margin-bottom: 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 {
  height: $input-height-sm;
  padding: $padding-sm-vertical $padding-sm-horizontal;
  font-size: $font-size-sm;
  line-height: $line-height-sm;
  border-radius: $input-border-radius-sm;
}

.form-control-lg {
  height: $input-height-lg;
  padding: $padding-lg-vertical $padding-lg-horizontal;
  font-size: $font-size-lg;
  line-height: $line-height-lg;
  border-radius: $input-border-radius-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;
}


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

.radio,
.checkbox {
  position: relative;
  display: block;
  // margin-top:    ($spacer * .75);
  margin-bottom: ($spacer * .75);

  label {
    padding-left: 1.25rem;
    margin-bottom: 0;
    font-weight: normal;
    cursor: pointer;

    // When there's no labels, don't position the input.
    input:only-child {
      position: static;
    }
  }
}
.radio input[type="radio"],
.radio-inline input[type="radio"],
.checkbox input[type="checkbox"],
.checkbox-inline input[type="checkbox"] {
  position: absolute;
  margin-top: .25rem;
  // margin-top: 4px \9;
  margin-left: -1.25rem;
}

.radio + .radio,
.checkbox + .checkbox {
  // Move up sibling radios or checkboxes for tighter spacing
  margin-top: -.25rem;
}

// Radios and checkboxes on same line
.radio-inline,
.checkbox-inline {
  position: relative;
  display: inline-block;
  padding-left: 1.25rem;
  margin-bottom: 0;
  font-weight: normal;
  vertical-align: middle;
  cursor: pointer;
}
.radio-inline + .radio-inline,
.checkbox-inline + .checkbox-inline {
  margin-top: 0;
  margin-left: .75rem;
}

// Apply same disabled cursor tweak as for inputs
// Some special care is needed because <label>s don't inherit their parent's `cursor`.
//
// Note: Neither radios nor checkboxes can be readonly.
input[type="radio"],
input[type="checkbox"] {
  &:disabled,
  &.disabled,
  fieldset[disabled] & {
    cursor: $cursor-disabled;
  }
}
// These classes are used directly on <label>s
.radio-inline,
.checkbox-inline {
  &.disabled,
  fieldset[disabled] & {
    cursor: $cursor-disabled;
  }
}
// These classes are used on elements with <label> descendants
.radio,
.checkbox {
  &.disabled,
  fieldset[disabled] & {
    label {
      cursor: $cursor-disabled;
    }
  }
}


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

.has-feedback {
  // Enable absolute positioning
  position: relative;

  // Ensure icons don't overlap text
  .form-control {
    padding-right: ($input-height-base * 1.25);
  }
}
// Feedback icon
.form-control-feedback {
  position: absolute;
  top: 0;
  right: 0;
  z-index: 2; // Ensure icon is above input groups
  display: block;
  width: $input-height-base;
  height: $input-height-base;
  line-height: $input-height-base;
  text-align: center;
  pointer-events: none;
}
.input-lg + .form-control-feedback,
.input-group-lg + .form-control-feedback {
  width: $input-height-lg;
  height: $input-height-lg;
  line-height: $input-height-lg;
}
.input-sm + .form-control-feedback,
.input-group-sm + .form-control-feedback {
  width: $input-height-sm;
  height: $input-height-sm;
  line-height: $input-height-sm;
}

// Form validation states
.has-success {
  @include form-control-validation($state-success-text, $state-success-text, $state-success-bg);
}
.has-warning {
  @include form-control-validation($state-warning-text, $state-warning-text, $state-warning-bg);
}
.has-error {
  @include form-control-validation($state-danger-text, $state-danger-text, $state-danger-bg);
}

// Reposition feedback icon if input has visible label above
.has-feedback label {

  ~ .form-control-feedback {
    top: ($line-height-computed + 5); // Height of the `label` and its margin
  }

  &.sr-only ~ .form-control-feedback {
    top: 0;
  }
}


// Help text
//
// Apply to any element you wish to create light text for placement immediately
// below a form control. Use for general help, formatting, or instructional text.

.help-block {
  display: block; // account for any element using help-block
  margin-top: .25rem;
  margin-bottom: .75rem;
  color: lighten($text-color, 25%); // lighten the text some for contrast
}


// 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).
//
// Heads up! This is mixin-ed into `.navbar-form` in navbars.less.

.form-inline {

  // Kick in the inline
  @include media-breakpoint-up(sm) {
    // Inline-block all the things for "inline"
    .form-group {
      display: inline-block;
      margin-bottom: 0;
      vertical-align: middle;
    }

    // In navbar-form, 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 {
      display: inline-table;
      vertical-align: middle;

      .input-group-addon,
      .input-group-btn,
      .form-control {
        width: auto;
      }
    }

    // Input groups need that 100% width though
    .input-group > .form-control {
      width: 100%;
    }

    .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.
    .radio,
    .checkbox {
      display: inline-block;
      margin-top: 0;
      margin-bottom: 0;
      vertical-align: middle;

      label {
        padding-left: 0;
      }
    }
    .radio input[type="radio"],
    .checkbox input[type="checkbox"] {
      position: relative;
      margin-left: 0;
    }

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