Post Grid problem: Menu bar shifts to the left

Hello,

I am using post grid to create the news page. However adding post grid element to the page causes the menu bar to shift to the left. Removing post grid solves the problem. Adding post grid to any other page causes the menu bar to shift to the left.
Why is post grid causing this error and how could it be solved?

Thank you

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