A Layout is a container that can hold a main content area with an optional navigation drawer (on the left) and/or sidebar (on the right). According to the [material design spec](https://www.google.com/design/spec/layout/structure.html#structure-side-nav), the left drawer is typically used for navigation or identity-based content, while the right sidebar is secondary content related to the main content.
The primary layout component. This acts as the main container that all subcomponents are placed within. The layout is typically placed so as to fill the entire screen, although it does not have to be.
The Layout's subcomponents can alter their appearance and behavior based on the current screen size. The layout uses the screen breakpoints described in the [material design spec](https://www.google.com/design/spec/layout/responsive-ui.html#responsive-ui-breakpoints), namely:
The components also make use of [standard increments](https://www.google.com/design/spec/layout/metrics-keylines.html#metrics-keylines-sizing-by-increments), which is a unit equal to the height of the action bar. At mobile sizes (<`xs`) the increment is 56px. On larger screens, it is 64px.
The content areas of all three of the subcomponents (`NavDrawer`, `Panel`, and `Sidebar`) use flexbox column layouts set to fill the entire height of the containing `Layout`. The column layout lends itself well to the fixed header/scrolling content that will frequently inhabit these components. By default, these components also do not scroll content vertically so that you can control where scrolling occurs. (For example, see the content of the `Panel` in the sample.)
If the column layout does not suit your needs, simply fill the content area with an element with `flex` set to 1, and use whatever layout you like within it.
The [navigation drawer](https://www.google.com/design/spec/patterns/navigation-drawer.html) slides in from the left and usually holds [the application's main navigation](https://www.google.com/design/spec/layout/structure.html#structure-side-nav). The drawer's width is based on the screen size:
The drawer can be docked to the left side of the screen or can float temporarily as an overlay. You can control the drawer's display manually `active` and `pinned` properties, and can also specify a breakpoint at which the drawer automatically becomes permanently docked.
The `Panel` is the main content area within a `Layout`. It is a full-height flexbox column that takes up all remaining horizontal space after the `NavDrawer` and `Sidebar` are laid out.
The `Sidebar` is an extra drawer that docks to the right side of the `Layout`. The sidebar's width can be set either to a multiple of the "standard increment" (1 - 12 increments) or as a percentage of the parent `Layout` width (25%, 33%, 50%, 66%, 75%, 100%). Regardless of the width set, at mobile screen sizes the sidebar acts like a full-screen dialog that covers the entire screen (see [examples](https://www.google.com/design/spec/layout/structure.html#structure-side-nav)).
The `Layout` is meant to be used near the top level of your application, so that it occupies the entire screen. However, it is possible to nest one layout inside another:
The main reason you would want to do something like this would be so that the navigation could be rendered at a high level, while the contents of the inner `Layout` would be controlled by react-router or something like that.
