Remove border on full width page template

In the Perth theme, I would like to remove the border that surrounds the content on the full-width template. For example on this page: http://smalldata.se/?page_id=2980. In the top left corner of the page, right above “Research & Analysis”, I would like to get rid off the border. How can I achieve that?

I’m not seeing any border. Have you figured this out?

Hi Vlad, yes, I have. Thank you!

Hi Seb, would you mind sharing how you solve the problem?? I would like to remove the border as well. Thanks in advance!