discourse/app/assets/stylesheets/common/select-box-kit/pinned-button.scss

#topic-footer-buttons {
  .pinned-button {
    min-width: auto;
    margin: 10px 0 5px 0;

    &.is-hidden {
      display: none;
    }

    .btn {
      margin: 0;
    }

    .reason {
      line-height: 16px;
      margin: 0 0 0 10px;
    }
  }
}

.pinned-button {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: start;
      -ms-flex-pack: start;
          justify-content: flex-start;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  margin: 0;
  min-width: auto;

  .pinned-options {
    display: -webkit-inline-box;
    display: -ms-inline-flexbox;
    display: inline-flex;
  }

  .pinned-options {
    .select-box-kit-body {
      min-width: unset;
      max-width: unset;
      width: 550px;
    }
  }
}