HEADER (centered, sticky, full width outside red box, content centered inside)
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LEFT RAIL
Category 1
Category 2
Category 3
Category 4
MAIN CONTENT (700px, centered)
Content block 1
Content block 2
Content block 3
Content block 4
Content block 5
RIGHT RAIL
Preview 1
Preview 2
Preview 3
Preview 4
SAVEBAR (centered to page-container width, at bottom)