# Astro Use this playbook to build a content or marketing website with Astro. The result is a static site that ships HTML first. It has a typed component system, one layout per page type, optimized images, one URL per page, complete head metadata, and security headers. This guidance targets Astro 7. Astro 7 replaced the compiler and the default Markdown processor, so advice for older versions is often wrong. The basis is the Astro 7 documentation, the Astro source and changelog, and GitHub issues that report real failures. Recheck the linked documentation before each Astro major release, and before you start a new site. The one rule: build every page from components. A page file selects a layout, loads data, and composes components. It holds no styles and no styled markup of its own. When markup appears twice, or when an element carries styles, that markup is a component. ## Core model An Astro site has four layers. Each layer has one job and one invariant. | Layer | Location | Job | Invariant | |---|---|---|---| | Pages | `src/pages/` | Map a URL to a layout and components | Holds no `