chromium/ash/webui/common/resources/bluetooth/bluetooth_pairing_request_code_page.html

<style>
  #pageBody {
    align-items: center;
    display: flex;
    flex-direction: column;
    justify-content: center;
  }

  #message {
    margin-bottom: 56px;
  }

  #pin {
    width: 336px;
  }
</style>
<bluetooth-base-page
    on-pair="onPairClicked_"
    button-bar-state="[[buttonBarState_]]">
  <div slot="page-body" id="pageBody">
    <div id="message">
      [[getMessage_(device.*)]]
    </div>
    <cr-input
        id="pin"
        minlength="1"
        maxlength="[[getMaxlength_(authType)]]"
        type="text"
        aria-label="[[getMessage_(device.*)]]"
        value="{{pinCode_}}"
        auto-validate >
    </cr-input>
  </div>
</bluetooth-base-page>