Please help, the website vibrates and the maker denies

lease help, the website vibrates and the maker denies

I bought a theme from Yithemes. On my PC vibrates and flashes the website. Their demo vibrates too. I asked them a few times to solve the problem and each time they say they see no vibration. The only website that vibrates om my PC is that of that of Yithemes.

Go to their demo:
http://demo.yithemes.com/tyrion/

Refresh the site a few times and Watch to the main navigation that vibrates.

Or go to “shorcodes” and click on some elements of the subnavigation (shortcodes) and look at the main navigation that vibrates.
My pc resolution: 1920×1080

Please help, no one likes vibrating websites.