Create a web form that includes a field for a phone number input. The field should only accept valid phone numbers with the following format: (XXX) XXX-XXXX. The form should also include validation to ensure that the phone number input is not left empty and that it contains only numbers, dashes, spaces, and parentheses. Provide clear error messages for invalid input and ensure that the form is easily accessible and easy to use on both desktop and mobile devices.
This prompt doesn't seem malicious.