User blog comment:Sarah Manley/Test the Expanded Wiki Navigation/@comment-1411998-20111010122329/@comment-1613840-20111010225607

actually if you look further down at line 219 it states .navbackground is parent-container and has width: 729px; .subnav-2 is child-container and has width: 100%;

This means maximum width of parent-container - so it is 729px Thanks for checking so closely though:)