# BLOCK_TAGS

**Kind:** Constant

**Source:** [`atloria-monorepo/apps/web/src/components/Viewer/blockNesting.ts`](https://github.com/sherkety/atloria/blob/main/atloria-monorepo/apps/web/src/components/Viewer/blockNesting.ts#L20)

Which markdown children our component map renders as BLOCK-level markup.

This is a server-rendering correctness rule, not a styling preference.
Markdown puts a standalone image in its own paragraph, so `![shot](url)`
reaches the renderer as `<p><img></p>` — and CustomImage renders that img as a
<figure>, which is not legal inside a <p>. A browser parsing that HTML closes
the <p> before the <figure>, so the DOM built from our server HTML no longer
matches the tree React expects: hydration fails (React #418) and React throws
the ENTIRE server-rendered page away and re-renders it in the browser. The
page still looks right, which is what makes it dangerous — server rendering is
silently undone on exactly the pages that carry screenshots.

Lives in its own module (rather than inside MarkdownRenderer) so it can be
unit-tested: MarkdownRenderer pulls in ESM-only `react-markdown`, which this
app's jest transform cannot load.