Hello, @Kazi Sabit,
1. Regarding Border, there is no such extra border, but it is the border of the above section, I have marked in this screenshot: https://postimg.cc/Cz2gMpp4
2. I have checked your site and there is no such right-side gap on your site as in your provided screenshot.
Your provided screenshot: https://prnt.sc/Fw9efoDihNL4
My laptop screenshot: https://postimg.cc/HJhWf8sT
Regards 8Themes Team.