Hello, @Kazi Sabit,
1. Please copy and paste the below-given CSS code to XStore >> Theme Settings >> Theme Custom CSS and under the Mobile Custom CSS section and change the values of the padding in the given code as per your requirements.
.et-advance-tabs .et-tabs-content .clearfix.arrows-hover {
padding: 5px !important;
}
2. And again your site element which you showed in your provided screenshot, does not have the border, please see this screenshot: https://postimg.cc/1gnxLnNc
Regards 8Themes Team.