[Theme: Blaskan] Content/sidebar widths

I am working on a child-theme for Blaskan, and not making too many changes – BUT: There is a major thing I’d like to be able to fiddle with, but I don’t really find where to do it, and I’m afraid to screw up the responsivity of the theme. 

What I want to do it change the width of the content-area and the sidebar.  I’m working with a wide layout with one sidebar, and find the content area a tiny bit too wide (but the narrow one is on the other hand way too narrow for my liking).  I also would like to add some white space between the content/post area and the sidebar. 

I just don’t find where these things are specified in the css – I find padding on top of the sidebar, but nothing about the width…?  I suspect this has to do with the responsiveness of the theme, but it should none the less be possible to fiddle with – shouldn’t it? 

Umm, no.  I’m working locally on this, and my actual site uses a completely different (non-responsive) theme. 

I guess I could make a screenshot, but this is the standard settings that come with the theme options.  I haven’t made any changes to the width settings yet – I’m pretty much asking “where do I start” with this.  I don’t really see what good a screenshot would do. 

Well, my local version of the site runs on MAMP and functions like any other online WP-installation – I would guess the weirdness you’re experiencing comes from using HTML generated from “the browser’s version” of it.  Plausible? 

And yes, the fact that I can’t find width specified anywhere IS my problem, and the reason I posted here.  Where can this be hiding, if not specified in the css?