> ## Documentation Index
> Fetch the complete documentation index at: https://docs.formepdf.com/llms.txt
> Use this file to discover all available pages before exploring further.

# HTML Input

> Render the HTML and print CSS you already have to paginated PDF — no headless browser. A documented subset with named warnings for everything outside it.

Forme 0.14 adds a second front door to the engine: **`@formepdf/html`** renders HTML + print CSS to PDF through the same Rust/WASM engine that renders JSX components. No headless browser, no Chromium cold start.

```bash theme={null}
# CLI — zero config
npx @formepdf/html invoice.html -o invoice.pdf

# with a separate stylesheet, page setup, and fonts
npx @formepdf/html report.html --css print.css --page-size Letter --margin 36 --font "Inter=Inter.ttf"
```

```ts theme={null}
// Library
import { renderHtml } from "@formepdf/html";

const { pdf, warnings } = await renderHtml(html, { css, fonts });
```

## The subset — the constitution

This is a deliberately **documented subset** of HTML/CSS, in the spirit of Satori — but page-native. Everything supported is listed below and tested. Everything outside the subset lands in the `warnings` list at render time, named, with a remedy where one exists. Nothing fails silently.

### Paged media — the point of the whole thing

| Supported                                                                                                                | Not supported (warned)                                                   |
| ------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------ |
| `@page` `size` (named, dimensions, `landscape`) and `margin`                                                             | `@page` `bleed` / `marks`                                                |
| `@page :first` — different margins, headers off the title page                                                           | `:left` / `:right` page variants                                         |
| Margin boxes (`@top-center`, `@bottom-right`, …) for running headers/footers                                             |                                                                          |
| Page counters — `counter(page)` and `counter(pages)`                                                                     |                                                                          |
| `break-before` / `break-after` / `break-inside: avoid` (+ legacy `page-break-*` aliases)                                 |                                                                          |
| `orphans` / `widows`                                                                                                     |                                                                          |
| `@media` media-type evaluation — `print` is the native media type; feature queries evaluate against the page content box | `prefers-color-scheme`, `not` conditions (excluded with a named warning) |
| `<thead>` repetition across page breaks; table-cell overflow preservation                                                |                                                                          |

### Elements

| Supported                                                                                                                          | Not supported                                                       |
| ---------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------- |
| Block containers: `div`, `section`, `article`, `header`, `footer`, `main`, `aside`, `nav`, `address`, `figure`, `blockquote`, `hr` | JavaScript of any kind (`<script>` skipped)                         |
| `h1`–`h6`, `p`, `br`                                                                                                               | `<canvas>`, `<video>`, `<audio>`, `<iframe>`, forms                 |
| Inline: `span`, `b`/`strong`, `i`/`em`, `u`, `s`/`del`, `a`, `small`, `code`, `mark`, `sub`, `sup`                                 | Inline `<img>` mid-paragraph                                        |
| Tables: `table`, `thead`, `tbody`, `tfoot`, `tr`, `td`, `th` + `colspan`/`rowspan`                                                 |                                                                     |
| Lists: `ul`, `ol` (+ `start`), `li`                                                                                                |                                                                     |
| `img` (block-level) — data URIs and local files                                                                                    | External `http(s)` image fetching                                   |
| `<style>` blocks; the CLI inlines **local** `<link rel="stylesheet">`                                                              | Remote stylesheets — never fetched, warned with the href and remedy |

### Selectors

| Supported                                                                                 | Not supported (selector skipped, warned)                              |
| ----------------------------------------------------------------------------------------- | --------------------------------------------------------------------- |
| Type, class, id, universal; compounds                                                     | Pseudo-elements (`::before`, `::after`)                               |
| Descendant and child combinators; grouping                                                | Attribute selectors, sibling combinators                              |
| `:first-child`, `:last-child`, `:nth-child(even\|odd\|an+b)`                              | `:only-child` and remaining tree pseudo-classes                       |
| `:first-of-type`, `:last-of-type`, `:nth-of-type`, `:nth-last-child`, `:nth-last-of-type` | Interaction pseudo-classes (`:hover`) — permanent: print has no hover |
| Full cascade with `!important`                                                            |                                                                       |

### Properties

The full property table lives in the [package README](https://github.com/formepdf/forme/blob/main/html/README.md) — margins with CSS margin collapsing, borders (solid/dashed/dotted with Chrome-matched dash metrics), `border-collapse` emulation, min/max width constraints (the centered-column idiom works), font fallback chains, `text-align: justify` with real Knuth-Plass distribution, `text-transform`, `letter-spacing`, `vertical-align` on cells, flexbox, and relative/absolute positioning.

Notable exclusions, all warned by name: `float`, CSS Grid, CSS variables, `position: fixed/sticky`, transforms, gradients, `@font-face` fetching (use `options.fonts` / `--font` — see the [web-fonts migration recipe](https://github.com/formepdf/forme/blob/main/html/README.md)).

## The warnings contract

```
$ npx @formepdf/html letterhead.html -o letterhead.pdf
warning: unsupported property: text-transform-origin
```

Every warning names the thing it skipped: the property, the selector, the stylesheet href, the `@font-face` family. If a render is silent, the document used only the subset — and what you got is what the subset defines.

## Migrating

* [Replacing Puppeteer](/replacing-puppeteer)
* [Migrating from wkhtmltopdf](/guides/migrating-from-wkhtmltopdf)
* [Migrating from DomPDF](/guides/migrating-from-dompdf)