Hi,

You can try add more this code to Customize > Custom CSS to do that:

@media only screen and (min-width: 1170px){
body.single .container.penci_sidebar,
body.page-template-default .container-single-page {
    width: 1300px;
}
.penci-single-style-10 .penci-single-s10-content, .container.penci_sidebar #main{ padding-right: 80px; }
}

Change value 1300 to container width as you want and value 80 to the padding between content & sidebar.

Best Regards,

PenciDesign