Vyasa treats D2 as a first-class diagram format for pages that need architecture, grouped systems, or staged reveal rather than hand-drawn prose. The renderer expects a d2 fence in Markdown, then lets the client runtime handle sizing, zoom, theme-aware redraw, and fullscreen behavior. This guide is about authoring D2 blocks that fit naturally into a live document, not about every D2 feature. The mental model is simple: keep the diagram source in the page, use frontmatter for container behavior, and only reach for animation when the reveal itself explains something.