Layout Hierarchy
Use
This page describes the layout hierarchy of Web pages, which defines the options for nesting page elements. In short, this page tells designers, which page element can be placed into which container element - including placing containers inside containers.
The layout hierarchy is the basis for establishing textual layout rules for pages and page sections. The main goal of such rules is to prevent overly complex and visually cluttered pages caused by excessive nesting.
Note
These rules do not comprise the spacing between and within elements.
From Containers to the Layout Hierarchy
Layout Hierarchy for iViews and Web Applications