Menu background Full width?

Hi. I love this plugin but I have one issue. I can’t get it to truly go full width. Everything about this right now is showing at width: 100% but you can see it’s like 1-2% from the edge on both sides and I want it to stretch across the entire width. I’m guessing there is a setting I need to check, but can’t tell.

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