central part that "pushes" columns down.
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
part with content occupying rest of width
fixed width footer: 750px