I am trying to build a website that will have fixed center alignment that will adjust to different screens, but have the content scroll vertically under the header/footer. something similar to this: LUNDLUND : Stylist.
Download this file, which follows my original instructions. Note how the content slides under the header (I made the header background translucent so you can see it happening.
Draw an HTML box on the page and double-click into it to create your inline content element, don’t double-click into the page itself. You can make it work if you do the latter, but it’s more effort for no gain.
Insert some (any) content into the elements you draw before you set their height to undefined (by clicking on the icon left of the height field in the Inspector). Items with undefined height and no content shrink to zero-height and are very difficult to select in the layout.