Stretch navigation to 100% | WordPress.org

I want to stretch the navigation to full page width, which is 1100px wide, but when I add the width to my custom CSS, it shifts the menu text to the left.

Here’s the CSS:

.menu-primary-menu-container {
background-color: #CAE0DE;
margin-top: 15px;
margin-bottom: -18px;
border-top: 2px solid #F8DF00;
width: 1100px;
}

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