It is definitely possibly, but the exact code you need to use is going to depend on what is cause the line in the first place. I don't see any text, so have you already tried hiding the section header? If so, the line is usually just a border setting you can change with CSS.

My first recommendation is always to open the page, right-click the line, and figure out exactly what styling is causing it so you don't bang your head against the wall trying to identify the culprit. Once you find the associated element/styling, changing it shouldn't take much.