Is there an easy way to have my posts and pages styled completely the same?

I’m using monochrome lite

https://graphpaperpress.com/2008/02/06/monochrome-lite/

This is one of my pages:
https://www.berichandcreamy.com/

and here’s a sample post:

https://www.berichandcreamy.com/2009/10/speak-easy-sway-videodrome-at-el-dorado-and-broadway-pizza/

I’d like to clone/copy make the theme the same for pages and posts so that all my posts singles and lists look exactly like pages. I don’t use the right side bar and I think the formatting is messing up my flickr albums in posts. I can figure out how to delete the top border of the side bar but I don’t know how to move the text margins across the screen.

I’m hoping I’m only a few cut and pastes away before matching it up!