core/skin/assets/plugins/select2/css/select2-bootstrap4.css

.select2-container--bootstrap4 .select2-selection--single {
  height: calc(1.5em + 0.75rem + 2px) }
  .select2-container--bootstrap4 .select2-selection--single .select2-selection__placeholder {
    color: #757575;
    line-height: calc(1.5em + 0.75rem); }
  .select2-container--bootstrap4 .select2-selection--single .select2-selection__arrow {
    position: absolute;
    top: 50%;
    right: 3px;
    width: 20px; }
    .select2-container--bootstrap4 .select2-selection--single .select2-selection__arrow b {
      top: 60%;
      border-color: #343a40 transparent transparent transparent;
      border-style: solid;
      border-width: 5px 4px 0 4px;
      width: 0;
      height: 0;
      left: 50%;
      margin-left: -4px;
      margin-top: -2px;
      position: absolute; }
  .select2-container--bootstrap4 .select2-selection--single .select2-selection__rendered {
    line-height: calc(1.5em + 0.75rem); }

.select2-search--dropdown .select2-search__field {
    border: 1px solid rgb(255 255 255 / 29%);
    border-radius: 0.25rem;
    background: rgb(255 255 255 / 27%);
    color: #fff;	}

.select2-results__message {
  color: #6c757d; }

.select2-container--bootstrap4 .select2-selection--multiple {
  min-height: calc(1.5em + 0.75rem + 2px) !important; }
  .select2-container--bootstrap4 .select2-selection--multiple .select2-selection__rendered {
    -webkit-box-sizing: border-box;
            box-sizing: border-box;
    list-style: none;
    margin: 0;
    padding: 0 8px;
    width: 100%; }
    .select2-container--bootstrap4 .select2-selection--multiple .select2-selection__rendered .select2-search__field {
      width: 100% !important; }
  .select2-container--bootstrap4 .select2-selection--multiple .select2-selection__choice {
    color: #fff;
    border: 1px solid rgb(255 255 255 / 32%);
    border-radius: 0.2rem;
    padding: 0;
    padding-right: 5px;
    cursor: pointer;
    float: left;
	  background: #171717;
    margin-top: 0.3em;
    margin-right: 5px; }
  .select2-container--bootstrap4 .select2-selection--multiple .select2-selection__choice__remove {
    color: #bdc6d0;
    font-weight: bold;
    margin-left: 3px;
    margin-right: 1px;
    padding-right: 3px;
    padding-left: 3px;
    float: left; }
    .select2-container--bootstrap4 .select2-selection--multiple .select2-selection__choice__remove:hover {
      color: #343a40; }
  .select2-container--bootstrap4 .select2-selection--multiple .select2-selection__clear {
    float: none;
    margin-right: 0;
    position: absolute !important;
    top: 0;
    right: 0.7em; }

.select2-container {
  display: block; }
  .select2-container *:focus {
    outline: 0; }

.input-group .select2-container--bootstrap4 {
  -webkit-box-flex: 1;
      -ms-flex-positive: 1;
          flex-grow: 1; }

.input-group-prepend ~ .select2-container--bootstrap4 .select2-selection {
  border-top-left-radius: 0;
  border-bottom-left-radius: 0; }

.input-group > .select2-container--bootstrap4:not(:last-child) .select2-selection {
  border-top-right-radius: 0;
  border-bottom-right-radius: 0; }

.select2-container--bootstrap4 .select2-selection {
  background-color: rgb(0 0 0 / 15%);
  border: 1px solid rgb(255 255 255 / 15%);
  border-radius: 0.25rem;
  -webkit-transition: border-color 0.15s ease-in-out, -webkit-box-shadow 0.15s ease-in-out;
  transition: border-color 0.15s ease-in-out, -webkit-box-shadow 0.15s ease-in-out;
  transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
  transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out, -webkit-box-shadow 0.15s ease-in-out;
  width: 100%; }
  @media (prefers-reduced-motion: reduce) {
    .select2-container--bootstrap4 .select2-selection {
      -webkit-transition: none;
      transition: none; } }

.select2-container--bootstrap4.select2-container--focus .select2-selection {
  border-color: rgb(255 255 255 / 30%);
  -webkit-box-shadow: 0 0 0 0.2rem rgb(255 255 255 / 25%);
          box-shadow: 0 0 0 0.2rem rgb(255 255 255 / 25%); }

.select2-container--bootstrap4.select2-container--focus.select2-container--open .select2-selection {
  border-bottom: none;
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0; }

.select2-container--bootstrap4.select2-container--disabled .select2-selection, .select2-container--bootstrap4.select2-container--disabled.select2-container--focus .select2-selection {
  background-color: #e9ecef;
  cursor: not-allowed;
  border-color: #ced4da;
  -webkit-box-shadow: none;
          box-shadow: none; }

.select2-container--bootstrap4.select2-container--disabled .select2-search__field, .select2-container--bootstrap4.select2-container--disabled.select2-container--focus .select2-search__field {
  background-color: transparent; }

select.is-invalid ~ .select2-container--bootstrap4 .select2-selection,
form.was-validated select:invalid ~ .select2-container--bootstrap4 .select2-selection {
  border-color: #dc3545; }

select.is-valid ~ .select2-container--bootstrap4 .select2-selection,
form.was-validated select:valid ~ .select2-container--bootstrap4 .select2-selection {
  border-color: #28a745; }

.select2-container--bootstrap4 .select2-dropdown {
  border-color: #ced4da;
  border-radius: 0; }
  .select2-container--bootstrap4 .select2-dropdown.select2-dropdown--below {
    border-top: none;
    border-bottom-right-radius: 0.25rem;
    border-bottom-left-radius: 0.25rem; }
  .select2-container--bootstrap4 .select2-dropdown.select2-dropdown--above {
    border-top: 1px solid #ced4da;
    border-top-left-radius: 0.25rem;
    border-top-right-radius: 0.25rem; }
  .select2-container--bootstrap4 .select2-dropdown .select2-results__option[aria-selected=true] {
    background-color: #171717; }

.select2-container--bootstrap4 .select2-results__option--highlighted,
.select2-container--bootstrap4 .select2-results__option--highlighted.select2-results__option[aria-selected=true] {
  background-color: rgb(255 255 255 / 24%);
  color: #ffffff; }

.select2-container--bootstrap4 .select2-results__option[role=group] {
  padding: 0; }
  .select2-container--bootstrap4 .select2-results__option[role=group] .select2-results__options--nested .select2-results__option {
    padding-left: 1em; }

.select2-container--bootstrap4 .select2-results > .select2-results__options {
  max-height: 15em;
  overflow-y: auto; }

.select2-container--bootstrap4 .select2-results__group {
  padding: 6px;
  display: list-item;
  color: #6c757d; }

.select2-container--bootstrap4 .select2-selection__clear {
  width: 0.9em;
  height: 0.9em;
  line-height: 0.75em;
  padding-left: 0.15em;
  margin-top: 0.7em;
  border-radius: 100%;
  background-color: #c8c8c8;
  color: #f8f9fa;
  float: right;
  margin-right: 0.3em; }
  .select2-container--bootstrap4 .select2-selection__clear:hover {
    background-color: #afafaf; }