Customizing The Homepage

I am trying to make the gray area on my home page larger. Does anyone know how to do that? It looks squished when using a browser on the pc. I’d like it to at least fill up 75% of the home page, but right now it probably fills up around 40%. I tried making the box larger but it doesn’t make the margin for the text go with it as well.

The page I need help with: [log in to see the link]