making sidebars larger

I read some of the posts about increasing sidebar size – I went into the style.css folder of my current theme (after trying numerous other themes out) and it seems as if everything is done as percentage. I don’t see specific px of the sidebar width in the css.

this is my site (work in progress): https://216.104.180.193/

any help appreciated! I have been working on this non-stop and keep coming upon issues with every theme that I can’t seem to get solved so then I try another one. Thank you.