Post text width and underlining menu items

Hi, Anders!

I can’t find in CSS the way to solve these two problems:

1. Make a block with text a little wider for all posts (make margins smaller)
2. Cancel the underlining of menu items on the left side of desktop’s version.

https://www.dropbox.com/s/oe2fs8u8oadk6ro/%D0%A1%D0%BD%D0%B8%D0%BC%D0%BE%D0%BA%20%D1%8D%D0%BA%D1%80%D0%B0%D0%BD%D0%B0%202019-02-26%20%D0%B2%2007.09.49.png?dl=0

Need your help, please.

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