---
url: /foundations/layout/scaffold/overview.md
description: >-
  A fundamental UI design structure that provides a standard platform for
  assembling key components
---

# Scaffold

A fundamental UI design structure that provides a standard platform for assembling key components

**Overview** · [Bars](bars.md) · [Rails](rails.md) · [Panes](panes.md)

![Scaffold](/assets/acd43809-mrodw83s-understanding-layout.Fo-wBEgJ.webp)

* The layout scaffold structures every piece of an adaptive layout into bars, rails, and [panes](panes.md "Panes are layout containers that house other components and elements within a single app. A pane can be: fixed, flexible, floating, or semi permanent.")
* Bars can frame the page to help people navigate through a product
* Rails create the perimeter space surrounding panes, creating space for elements like navigation and toolbars
* Panes hold a product’s primary content, adapting to [breakpoints](../breakpoints/overview.md "Breakpoints are opinionated window sizes where a layout changes to match available space, device conventions, and ergonomics (previously window size classes).") (previously window size classes) and other conditions

## Availability & resources

| Type           | Resource                                                                                                   | Status    |
| -------------- | ---------------------------------------------------------------------------------------------------------- | --------- |
| Design         | [M3 Design Kit (Figma)](https://www.figma.com/community/file/1035203688168086460)                          | Available |
|                | [Spacing system & tokens](../../../styles/spacing/overview.md)                                             | Available |
| Implementation | [Jetpack Compose: Rulers](https://developer.android.com/reference/kotlin/androidx/compose/ui/layout/Ruler) | Available |

![2 diagrams of mobile and desktop layouts, identifying the parts of a scaffold.](/assets/d1a4e1ed-mp3n7x8n-01.BdqVUHGk.webp)

1. Safety region
2. Bar
3. Pane
4. Rail