Wider text column in Magazine template?

You'll need to modify the CSS of the magazine template. Do you want to widen the width of the entire body, including the sidebar? Or just the text block?

I'm interested in having the text in the blog template (just the text block) wider, so I figured I'd jump in here. I see max_width in the css file, but I've never done any web dev so not sure where it's defined or if that's the thing to change.