discourse/app/assets/stylesheets/common/select-kit/group-dropdown.scss

.select-kit {
  &.combo-box {
    &.group-dropdown {
      min-width: auto;

      .combo-box-header {
        background: $primary-low;
        color: $primary;
        border: 1px solid transparent;
        padding: 4.5px 5px 4.5px 10px;
        font-size: $font-0;
        transition: none;

        .d-icon {
          opacity: 1;
          font-size: $font-0;
          margin: 0;
        }
      }

      &.is-expanded .tag-drop-header {
        border: 1px solid $tertiary;
        box-shadow: shadow("focus");
      }

      .select-kit-collection {
        display: flex;
        flex-direction: column;
        padding: 0;
        max-height: 300px;

        .collection-header {
          .group-dropdown-filter {
            white-space: nowrap;
            color: $primary;
            font-size: $font-down-1;
            line-height: $line-height-medium;
            font-weight: bold;
            display: block;
            padding: 10px 5px;

            &:hover {
              text-decoration: underline;
            }
          }
        }
      }

      .select-kit-filter .filter-input {
        width: auto;
      }

      .select-kit-body {
        width: auto;
        min-width: 150px;
        border-radius: 0;
        box-shadow: shadow("dropdown");
      }

      .select-kit-row {
        margin: 0;
        font-size: $font-down-1;
        font-weight: bold;
        color: $tertiary;

        &.no-content {
          font-weight: normal;
        }
      }

      &.is-expanded .select-kit-wrapper, .select-kit-wrapper {
        display: none;
      }
    }
  }
}