Hello, @Kazi Sabit,
I have checked your issue then I checked the same thing on our test site and found no issue it is working fine it means that the theme has no issue. You can see the result in this video: https://streamable.com/ldz2cv I have checked on your site that you are using third-party plugins as well. Also, you are not using the latest version of the theme on your site. In order to solve your issue please first update the theme and core plugin on your site to the latest version and disable the third-party plugins then check back to your site after clearing the browser cache.
https://xstore.helpscoutdocs.com/article/63-theme-update
https://xstore.helpscoutdocs.com/article/58-how-to-update-rate
Regards 8Themes Team.