The Aubrey template is designed to have a navigation that is short and sweet. If it goes over 60% of the screen width it will break across two lines. If you use navigation folders, this can be a bit of a mess.
To allow the navigation to take up more space, for example up to 90% of the width, add this following CSS.
.info-page-layout-poster #main-navigation { width:90%; }
If you're unsure how to add CSS to a Squarespace site see our helpful guide Adding CSS to Squarespace.
