“Contact Form 7” date field not working properly

I have installed a “Contact Form 7” plugin on following WP blog https://vsupholstery.com/ and I have added date field inside that form (form is located below slider). The problem was that the date field was not functional inside Firefox, IE and Safari, so I installed the additional plugin from this page http://wordpress.org/plugins/contact-form-7-datepicker/ . Now the date field is working OK and it shows the calendar when you click inside date field, but the calendar style does not work.

Any idea how to fix this problem since I tried many things and nothing works.

Thanks.