Side Bar Width on Home Page using Page Builder

It appears that pages have a side bar width of 300px. (I think)

But my home page side bar is narrower, I can tell because the “Newsletter” signup box is squished. 🙂

What is the CSS code to make the side bar wider. width=300px, but I don’t know the terms for the side bar on the home page. And would it go under the “Extra Class” option on the editing for the side bar or under Edit CSS??

Thanks!