bootstrap/scss/forms/_input-group.scss

@use "sass:map";
@use "sass:string";
@use "../variables" as *;
@use "../vendor/rfs" as *;
@use "../mixins/border-radius" as *;

//
// Base styles
//

@layer forms {
  .input-group {
    position: relative;
    display: flex;
    flex-wrap: wrap; // For form validation feedback
    align-items: stretch;
    width: 100%;

    > .form-control,
    > .form-select,
    > .form-floating {
      position: relative; // For focus state's z-index
      flex: 1 1 auto;
      width: 1%;
      min-width: 0; // https://stackoverflow.com/questions/36247140/why-dont-flex-items-shrink-past-content-size
    }

    // Bring the "active" form control to the top of surrounding elements
    > .form-control:focus,
    > .form-select:focus,
    > .form-floating:focus-within {
      z-index: 5;
    }

    // Ensure buttons are always above inputs for more visually pleasing borders.
    // This isn't needed for `.input-group-text` since it shares the same border-color
    // as our inputs.
    .btn {
      position: relative;
      z-index: 2;

      &:focus {
        z-index: 5;
      }
    }
  }


  // Textual addons
  //
  // Serves as a catch-all element for any text or radio/checkbox input you wish
  // to prepend or append to an input.

  .input-group-text {
    display: flex;
    align-items: center;
    padding: $input-group-addon-padding-y $input-group-addon-padding-x;
    @include font-size($input-font-size); // Match inputs
    font-weight: $input-group-addon-font-weight;
    line-height: $input-line-height;
    color: $input-group-addon-color;
    text-align: center;
    white-space: nowrap;
    background-color: $input-group-addon-bg;
    border: $input-border-width solid $input-group-addon-border-color;
    @include border-radius($input-border-radius);
  }


  // Sizing
  //
  // Remix the default form control sizing classes into new ones for easier
  // manipulation.

  .input-group-lg > .form-control,
  .input-group-lg > .form-select,
  .input-group-lg > .input-group-text,
  .input-group-lg > .btn {
    padding: $input-padding-y-lg $input-padding-x-lg;
    @include font-size($input-font-size-lg);
    @include border-radius($input-border-radius-lg);
  }

  .input-group-sm > .form-control,
  .input-group-sm > .form-select,
  .input-group-sm > .input-group-text,
  .input-group-sm > .btn {
    padding: $input-padding-y-sm $input-padding-x-sm;
    @include font-size($input-font-size-sm);
    @include border-radius($input-border-radius-sm);
  }

  .input-group-lg > .form-select,
  .input-group-sm > .form-select {
    padding-right: $form-select-padding-x + $form-select-indicator-padding;
  }


  // Rounded corners
  //
  // These rulesets must come after the sizing ones to properly override sm and lg
  // border-radius values when extending. They're more specific than we'd like
  // with the `.input-group >` part, but without it, we cannot override the sizing.

  // stylelint-disable-next-line no-duplicate-selectors
  .input-group {
    &:not(.has-validation) {
      > :not(:last-child):not(.dropdown-toggle):not(.dropdown-menu):not(.form-floating),
      > .dropdown-toggle:nth-last-child(n + 3),
      > .form-floating:not(:last-child) > .form-control,
      > .form-floating:not(:last-child) > .form-select {
        @include border-end-radius(0);
      }
    }

    &.has-validation {
      > :nth-last-child(n + 3):not(.dropdown-toggle):not(.dropdown-menu):not(.form-floating),
      > .dropdown-toggle:nth-last-child(n + 4),
      > .form-floating:nth-last-child(n + 3) > .form-control,
      > .form-floating:nth-last-child(n + 3) > .form-select {
        @include border-end-radius(0);
      }
    }

    $validation-messages: "";
    @each $state in map.keys($form-validation-states) {
      $validation-messages: $validation-messages + ":not(." + string.unquote($state) + "-tooltip)" + ":not(." + string.unquote($state) + "-feedback)";
    }

    > :not(:first-child):not(.dropdown-menu)#{$validation-messages} {
      margin-left: calc(-1 * #{$input-border-width});
      @include border-start-radius(0);
    }

    > .form-floating:not(:first-child) > .form-control,
    > .form-floating:not(:first-child) > .form-select {
      @include border-start-radius(0);
    }
  }
}