` shows as the text `

`. ## Frontmatter A page starts with YAML between two `---` lines. The first line of the file must be `---`. ```yaml --- title: Hot Jupiter summary: A gas giant so close to its star that its year lasts days. science_status: [observed, sim] categories: [Gas giants, Planet classes] aliases: [Hot Jupiters, Roaster] infobox: type: planet_class image: File:Hot_Jupiter_sim.avif host_star: "[[51 Pegasi]]" sim: entity: planet_class.GGH refs: - id: sudarsky2000 type: article-journal author: [{family: Sudarsky, given: David}, {family: Burrows, given: Adam}] title: "Albedo and Reflection Spectra of Extrasolar Giant Planets" container-title: The Astrophysical Journal volume: 538 page: 885-903 issued: 2000 DOI: 10.1086/309060 --- ``` - `categories` puts the page in those categories (names follow title rules, so `Gas giants` and `gas_giants` are the same category). A single category may be written as a plain string. - `aliases` create redirects to the page. `redirect: Target#Section` turns the page itself into a redirect. - Wikilinks inside `infobox` values are real links, and `File:` values in `infobox`, `image` and `hero` count as uses of that file. - `refs` is a list of CSL-JSON entries; each needs a text `id`. The site numbers them in the order you first cite them and prints the References list at the end. Do not write a References section yourself. - YAML here follows version 1.2: `yes`, `no` and `on` are plain words, `2026-09-27` stays text, and a repeated key is an error. ## Text CommonMark with the GitHub extensions: `*emphasis*`, `**strong**`, `` `code` ``, lists, `> quotes`, fenced code blocks, `---` rules, tables, task lists (`- [ ] item`), strikethrough with two tildes (`~~gone~~`), footnotes and bare URLs that become links. Tables need a header row and a delimiter row with at least one `|` or `:`: ```markdown | Body | a (AU) | Period (d) | |------|-------:|-----------:| | [[Earth]] | 1.00 | 365.26 | ``` Cells past the header's count are dropped. Number columns are set in mono and right-aligned automatically. ## Links **Wikilinks** point at wiki pages by title: - `[[Tau Ceti]]` links to `/wiki/Tau_Ceti`. - `[[Tau Ceti e|the planet]]` shows "the planet". - `[[Tau Ceti e#Atmosphere]]` links to a section; the anchor is the section heading as the site slugs it (`#atmosphere`). `[[#Orbit]]` links to a section of the same page. - `[[exoplanet]]s` shows "exoplanets": lower-case letters straight after the brackets join the link text. - Namespaces: `[[Talk:Tau Ceti]]`, `[[User:Name]]`, `[[File:Name.avif]]` (the file's page), `[[Pax Abyssi Wiki:Style guide]]`, `[[Draft:...]]`, `[[Template:...]]`, `[[Special:RecentChanges]]`. `[[:Category:Stars]]` links to a category page; `[[Category:Stars]]` works too but warns, because categories are set in the frontmatter. - Titles follow MediaWiki rules: spaces and underscores are the same, the first letter is capitalised for you, and `# < > [ ] | { }` cannot appear. A link to a page that does not exist yet shows in red. - Inside a table cell, write the pipe as `\|`: `[[Tau Ceti\|HD 10700]]`. - The link text is plain: `[[Page|*text*]]` shows the asterisks. **Ordinary links** use `[text](url)`, `` or a bare URL. Only `http`, `https` and `mailto` links are allowed; anything else is an error and is removed. Links off the site carry `rel="nofollow ugc noopener"` on the wiki and forum. **Images** written as `![alt](url)` are not used: add the image to the media library and use `::figure`, so every image carries its credit and licence. ## Headings `## Section`, `### Subsection`. The page title comes from the frontmatter, so start sections at `##`. Each heading gets an anchor made the GitHub way: lower case, punctuation removed, spaces to hyphens, a `-1`, `-2` suffix for repeats. `## Mass and radius` becomes `#mass-and-radius`. ## Maths `$...$` inline and a `$$` fence for display maths: ```markdown The equilibrium temperature $T_\mathrm{eq}$ is $$ T_\mathrm{eq} = T_\star \sqrt{\frac{R_\star}{2a}}\,(1 - A)^{1/4} $$ ``` Maths is rendered with KaTeX. Underscores and asterisks inside maths are safe. A dollar sign starts maths, so write money as `\$5`. ## Directives Directives add what Markdown lacks. There are three forms: | Form | Syntax | Used for | |---|---|---| | Text | `:name[label]{attributes}` inside a sentence | `:sim`, `:cite` | | Leaf | `::name[label]{attributes}` alone on a line | `::figure`, `::data-table`, `::orrery`, `::youtube` | | Container | `:::name[label]{attributes}`, content, then a closing `:::` line | `:::callout`, `:::spoiler`, `:::pullquote`, `:::figure`, `:::gallery`, `:::data-table` | Attributes: `key=value`, `key="value with spaces"` or `key='value'`, separated by spaces. Values cannot contain `<`, `>`, `=` or a backtick unless quoted. A leaf or container line must hold nothing after the closing `}`. Nesting: a closing line closes the innermost open container with at least as many colons, so give the outer container more colons: ```markdown ::::callout{type=science title="Outer"} :::figure{src="File:Inner.avif" alt="..."} The inner figure's caption. ::: :::: ``` A colon followed by a word with no brackets or braces (`10:30`, `File:Name.avif` in prose) is plain text. An unknown directive, or a known one in the wrong form (`::callout`), is an error: the editor preview shows a red box and the published page shows nothing. ### figure ```markdown ::figure{src="File:Hot_Jupiter_sim.avif" size=wide alt="A gas giant glowing red on its dayside" caption="A hot Jupiter from the sim."} :::figure{src="File:Transit.avif" alt="A light curve with a dip"} A caption with *emphasis*, a [[Transit method|link]] and maths $\Delta F$. ::: ``` - `src` (required): a `File:` title from the media library. - `alt` (required): what the image shows, for readers who cannot see it. `alt=""` marks a purely decorative image. - `caption`: one or two sentences; a container body or a `[label]` also works and may hold links and maths. Without one, the media page's caption is used. - `size`: `normal` (the text column, default), `medium` (a narrower inset, for portraits and discs), `wide` (1040 px in articles) or `full` (the window width in articles). - The credit and licence line always comes from the media page. `credit`, `licence` and `source` attributes are errors. - Figures are numbered in order: Figure 1, Figure 2. ### gallery ```markdown :::gallery{caption="Three giants from the same generator."} - File:Ice_giant.avif | A blue ice giant with faint cloud streaks | Ice giant - File:Green_giant.avif | A green giant with soft bands | Green giant ::figure{src="File:Ringed.avif" alt="A ringed giant at a low angle"} ::: ``` Each list item is `File:Name | alt text | caption` (alt is required). Leaf `::figure` lines work too. `size` defaults to `wide`. ### callout ```markdown :::callout{type=sim title="In Pax Abyssi"} How the sim generates this, with honest status. ::: ``` `type` is `note` (default), `warning`, `science`, `sim` (shown as "In the sim") or `lore`. `title` replaces the default label; `:::callout[Title]` also works. ### spoiler `:::spoiler{title="Campaign ending"}` ... `:::`. Collapsed until the reader opens it; works without JavaScript. ### pullquote `:::pullquote{attribution="Name, role"}` ... `:::`. At most one per 1,200 words. ### data-table Inline data, as a YAML body in a container: ```markdown :::data-table{caption="Inner planets" provenance=observed} - {name: Mercury, mass_earth: 0.055, radius_earth: 0.383} - {name: Venus, mass_earth: 0.815, radius_earth: 0.949} ::: ``` or with explicit columns (labels, units, alignment): ```markdown :::data-table{caption="Sudarsky classes" provenance=model} columns: - class - {key: teq, label: Temperature, unit: K, align: right} rows: - [I, "< 150"] - [II, "~250"] ::: ``` The body is YAML, not Markdown: `#` lines are YAML comments and links are not followed. Cells are plain values. A dataset from the current sim build, as a leaf: ```markdown ::data-table{dataset=ships columns="name,mass_t,thrust_kN" where="class=corvette" sort=-mass_t limit=10} ``` `columns` picks and orders columns, `where` keeps rows with `key=value` or `key!=value` (comma-separated, all must hold), `sort` orders by a column (`-` for descending), `limit` caps the rows. `provenance` is `catalogue`, `sim`, `fiction`, `observed` or `model` and prints the matching tag. ### sim `:sim{ref=ship.corvette.mass_t unit=t}` prints the value from the current build, with the build in a tooltip. `digits=1` fixes the decimals. `:sim[about 3,000]{ref=...}` shows the label if the value is unavailable. ### cite `:cite[sudarsky2000]`, `:cite[sudarsky2000, burrows2001]` (a semicolon or `@id` also work). Each id must be in the frontmatter `refs`. Citations show as [1] or [1, 2] and link to the References list. ### orrery `::orrery{system=tau-ceti focus=e height=480}` embeds the web orrery for a system (`system` is the orrery's slug; `height` in pixels, 100 to 9999). ### youtube `::youtube{id=dQw4w9WgXcQ title="A flyby" start=30}`. Nothing is fetched from YouTube until the reader presses play, and then only from youtube-nocookie.com. ## House style checks The editor and the save checks enforce the house style: - **No em dashes, ever** (U+2014). Use a hyphen, a colon, a comma pair or two sentences. Code and frontmatter are not exempt. - An en dash (U+2013) with a space on either side is a dash in disguise and is flagged. A plain hyphen is safest everywhere. - The copy checks also flag the stock writing tropes from the house style table: the antithesis twin (saying what a thing is not before what it is), empty intensifiers, inflated nouns and verbs, hook fragments, the reflective closer and the "if you are this or that" address. ## Messages you may see | Code | Severity | Meaning | |---|---|---| | `frontmatter-unclosed` | error | The opening `---` has no closing `---` line | | `frontmatter-yaml` | error | The frontmatter is not valid YAML (reported on line 1) | | `frontmatter-not-mapping` | error | The frontmatter is a list or a value, not `key: value` lines | | `refs-invalid` | error | `refs` is not a list, or an entry has no text `id` | | `refs-duplicate` | error | Two refs share an id | | `ref-unused` | warning | A ref is never cited | | `categories-invalid` | error | A category is not a list of valid names | | `em-dash` | error | An em dash | | `en-dash` | warning | An en dash used as a dash | | `unknown-directive` | error | No directive has that name | | `directive-kind` | error | A directive written in the wrong form (`::callout`) | | `directive-unclosed` | error | A container has no closing `:::` line | | `missing-attribute` | error | A required attribute is missing (`src`, `ref`, `system`, `id`, `dataset`) | | `invalid-attribute` | error | An attribute value is not allowed (`size=huge`, a bad `File:` title) | | `unknown-attribute` | warning | The directive has no such attribute | | `figure-missing-alt` | error | A figure or gallery item has no alt text | | `credit-override` | error | A figure sets its own credit or licence | | `cite-unknown` | error | A citation id is not in `refs` (or there are no refs) | | `cite-empty` | error | `:cite[]` with no id | | `unsafe-url` | error | A link uses a scheme other than http, https or mailto | | `image-syntax` | error | A Markdown image; use `::figure` | | `invalid-title` | error | A wikilink target breaks the title rules | | `category-link` | warning | `[[Category:X]]` links to the category page; set categories in the frontmatter | | `data-table-invalid` | error | A data table body is empty, not YAML, or not a table | Lines and columns count from 1; columns count characters (an emoji is one).