Can not center nav bar and submenu items alignment

Hello,

I am having trouble centering the unordered list in the main nav area without its container going to the far right of the page, making the website wider than it needs to be. I believe it has to do with the position being relative. However, when I take out that rule the menu just kind of jumbles together.

I am also having trouble getting the submenu items to align with their parent.

Please, your help would be huge! Thank you.