TwentyThirteen: Moving content on pages

Hello,

I need help. How should I move content on my pages further to the left, so the text would start where the first navigation item starts and end where the last navigation item ends.

Now:

https://193.2.241.108/wordpress/predstavitev-sole/

What I want:

https://shrani.si/f/T/Y5/4aBTFG9R/untitled.png

Any help would be appreciated.