header(required)
left column
(optional)
content area
(required)
right column
(optional)
footer
(optional)
header(required)
left column
(optional)
content area
(required)
footer
(optional)
header(required)
content area
(required)
right column
(optional)
footer
(optional)
header(required)
content area
(required)
footer
(optional)