Flat HTML matching the DOM from temp-headernavigation.cshtml
with sample Sitecore data: Home, Submit Science, and three children.
Model.Url → Home link /Model.Pages[0] → Submit Science (SubPagesExist = true)Page.SubPages → Yolo, Foo, Bar inside .dropdown-menu shadow_overlap-light br_black-1 br_solid br_1 br_raidus (stand-in for _HeaderSubNavigation)