moodle/theme/boost/scss/bootstrap/_custom-forms.scss

// Embedded icons from Open Iconic.
// Released under MIT and copyright 2014 Waybury.
// https://useiconic.com/open


// Checkboxes and radios
//
// Base class takes care of all the key behavioral aspects.

.custom-control {
  position: relative;
  display: block;
  min-height: (1rem * $line-height-base);
  padding-left: $custom-control-gutter;
}

.custom-control-inline {
  display: inline-flex;
  margin-right: $custom-control-spacer-x;
}

.custom-control-input {
  position: absolute;
  z-index: -1; // Put the input behind the label so it doesn't overlay text
  opacity: 0;

  &:checked ~ .custom-control-label::before {
    color: $custom-control-indicator-checked-color;
    @include gradient-bg($custom-control-indicator-checked-bg);
    @include box-shadow($custom-control-indicator-checked-box-shadow);
  }

  &:focus ~ .custom-control-label::before {
    // the mixin is not used here to make sure there is feedback
    box-shadow: $custom-control-indicator-focus-box-shadow;
  }

  &:active ~ .custom-control-label::before {
    color: $custom-control-indicator-active-color;
    background-color: $custom-control-indicator-active-bg;
    @include box-shadow($custom-control-indicator-active-box-shadow);
  }

  &:disabled {
    ~ .custom-control-label {
      color: $custom-control-label-disabled-color;

      &::before {
        background-color: $custom-control-indicator-disabled-bg;
      }
    }
  }
}

// Custom control indicators
//
// Build the custom controls out of psuedo-elements.

.custom-control-label {
  margin-bottom: 0;

  // Background-color and (when enabled) gradient
  &::before {
    position: absolute;
    top: (($line-height-base - $custom-control-indicator-size) / 2);
    left: 0;
    display: block;
    width: $custom-control-indicator-size;
    height: $custom-control-indicator-size;
    pointer-events: none;
    content: "";
    user-select: none;
    background-color: $custom-control-indicator-bg;
    @include box-shadow($custom-control-indicator-box-shadow);
  }

  // Foreground (icon)
  &::after {
    position: absolute;
    top: (($line-height-base - $custom-control-indicator-size) / 2);
    left: 0;
    display: block;
    width: $custom-control-indicator-size;
    height: $custom-control-indicator-size;
    content: "";
    background-repeat: no-repeat;
    background-position: center center;
    background-size: $custom-control-indicator-bg-size;
  }
}


// Checkboxes
//
// Tweak just a few things for checkboxes.

.custom-checkbox {
  .custom-control-label::before {
    @include border-radius($custom-checkbox-indicator-border-radius);
  }

  .custom-control-input:checked ~ .custom-control-label {
    &::before {
      @include gradient-bg($custom-control-indicator-checked-bg);
    }
    &::after {
      background-image: $custom-checkbox-indicator-icon-checked;
    }
  }

  .custom-control-input:indeterminate ~ .custom-control-label {
    &::before {
      @include gradient-bg($custom-checkbox-indicator-indeterminate-bg);
      @include box-shadow($custom-checkbox-indicator-indeterminate-box-shadow);
    }
    &::after {
      background-image: $custom-checkbox-indicator-icon-indeterminate;
    }
  }

  .custom-control-input:disabled {
    &:checked ~ .custom-control-label::before {
      background-color: $custom-control-indicator-checked-disabled-bg;
    }
    &:indeterminate ~ .custom-control-label::before {
      background-color: $custom-control-indicator-checked-disabled-bg;
    }
  }
}

// Radios
//
// Tweak just a few things for radios.

.custom-radio {
  .custom-control-label::before {
    border-radius: $custom-radio-indicator-border-radius;
  }

  .custom-control-input:checked ~ .custom-control-label {
    &::before {
      @include gradient-bg($custom-control-indicator-checked-bg);
    }
    &::after {
      background-image: $custom-radio-indicator-icon-checked;
    }
  }

  .custom-control-input:disabled {
    &:checked ~ .custom-control-label::before {
      background-color: $custom-control-indicator-checked-disabled-bg;
    }
  }
}


// Select
//
// Replaces the browser default select with a custom one, mostly pulled from
// http://primercss.io.
//

.custom-select {
  display: inline-block;
  width: 100%;
  height: $custom-select-height;
  padding: $custom-select-padding-y ($custom-select-padding-x + $custom-select-indicator-padding) $custom-select-padding-y $custom-select-padding-x;
  line-height: $custom-select-line-height;
  color: $custom-select-color;
  vertical-align: middle;
  background: $custom-select-bg $custom-select-indicator no-repeat right $custom-select-padding-x center;
  background-size: $custom-select-bg-size;
  border: $custom-select-border-width solid $custom-select-border-color;
  @if $enable-rounded {
    border-radius: $custom-select-border-radius;
  } @else {
    border-radius: 0;
  }
  appearance: none;

  &:focus {
    border-color: $custom-select-focus-border-color;
    outline: 0;
    box-shadow: $custom-select-focus-box-shadow;

    &::-ms-value {
      // For visual consistency with other platforms/browsers,
      // suppress the 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.
      // See https://github.com/twbs/bootstrap/issues/19398.
      color: $input-color;
      background-color: $input-bg;
    }
  }

  &[multiple],
  &[size]:not([size="1"]) {
    height: auto;
    padding-right: $custom-select-padding-x;
    background-image: none;
  }

  &:disabled {
    color: $custom-select-disabled-color;
    background-color: $custom-select-disabled-bg;
  }

  // Hides the default caret in IE11
  &::-ms-expand {
    opacity: 0;
  }
}

.custom-select-sm {
  height: $custom-select-height-sm;
  padding-top: $custom-select-padding-y;
  padding-bottom: $custom-select-padding-y;
  font-size: $custom-select-font-size-sm;
}

.custom-select-lg {
  height: $custom-select-height-lg;
  padding-top: $custom-select-padding-y;
  padding-bottom: $custom-select-padding-y;
  font-size: $custom-select-font-size-lg;
}


// File
//
// Custom file input.

.custom-file {
  position: relative;
  display: inline-block;
  width: 100%;
  height: $custom-file-height;
  margin-bottom: 0;
}

.custom-file-input {
  position: relative;
  z-index: 2;
  width: 100%;
  height: $custom-file-height;
  margin: 0;
  opacity: 0;

  &:focus ~ .custom-file-control {
    border-color: $custom-file-focus-border-color;
    box-shadow: $custom-file-focus-box-shadow;

    &::before {
      border-color: $custom-file-focus-border-color;
    }
  }

  @each $lang, $value in $custom-file-text {
    &:lang(#{$lang}) ~ .custom-file-label::after {
      content: $value;
    }
  }
}

.custom-file-label {
  position: absolute;
  top: 0;
  right: 0;
  left: 0;
  z-index: 1;
  height: $custom-file-height;
  padding: $custom-file-padding-y $custom-file-padding-x;
  line-height: $custom-file-line-height;
  color: $custom-file-color;
  background-color: $custom-file-bg;
  border: $custom-file-border-width solid $custom-file-border-color;
  @include border-radius($custom-file-border-radius);
  @include box-shadow($custom-file-box-shadow);

  &::after {
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    z-index: 3;
    display: block;
    height: calc(#{$custom-file-height} - #{$custom-file-border-width} * 2);
    padding: $custom-file-padding-y $custom-file-padding-x;
    line-height: $custom-file-line-height;
    color: $custom-file-button-color;
    content: "Browse";
    @include gradient-bg($custom-file-button-bg);
    border-left: $custom-file-border-width solid $custom-file-border-color;
    @include border-radius(0 $custom-file-border-radius $custom-file-border-radius 0);
  }
}