More possibilities.
Still just plain text.

KaTeX math & custom macros

Write inline math between single dollar signs and display math between double dollar signs. Bracket delimiters \( ... \) and \[ ... \], plus fenced math or katex blocks, are supported too.

Inline: $E = mc^2$

$$
\int_0^1 x^2\,dx = \frac{1}{3}
$$

```katex
\sqrt{a^2 + b^2}
```

Rendered in the live preview. Copy and download retain TeX source, not typeset math.

Open KaTeX & Mermaid preview settings to define custom macros as JSON, such as {"\\RR":"\\mathbb{R}"}, then use $\RR$. Macro settings apply only to this page session. Code samples and escaped dollar signs stay literal.

Mermaid diagrams

Create diagrams from text in a fenced mermaid block. Edit the source to update flowcharts, sequence diagrams, and other supported Mermaid diagram types.

```mermaid
flowchart LR
  A[Write Markdown] --> B[Preview]
  B --> C[Share your ideas]
```

```mermaid
sequenceDiagram
  Alice->>Bob: Review the draft
  Bob-->>Alice: Looks good
```

Rendered in the live preview. Choose Default, Neutral, Dark, or Forest in preview settings. Exports retain diagram source.

The preview uses plain diagram text without links, images, embedded HTML, backslash escapes, or configuration directives. Each diagram is limited to 12,000 characters and 200 edges. Math and diagrams together are limited to 60 blocks or expressions per document.

Tables

Separate cells with vertical bars, then add a row of hyphens below the header. A colon on the left, right, or both ends of a divider cell sets its alignment.

| Format | Best for | Portable? |
| :--- | :--- | :---: |
| Markdown | Writing | Yes |
| HTML | Publishing | Yes |
| PDF | Sharing | Yes |

Supported in this workspace.

Use a backslash before a literal vertical bar inside a cell. Tables work best for short text; large nested layouts are not portable.

Fenced code blocks

Place code between lines of three backticks. An optional language name tells compatible renderers how to highlight the code. Tildes can also form fences.

```javascript
function sayHello(name) {
  return `Hello, ${name}!`;
}
```

Code blocks are supported. This workspace displays code without syntax highlighting.

To show a block containing three backticks, use a surrounding fence with four or more backticks.

Task lists

Turn a bullet list into a checklist with square brackets. Use a space for an unchecked item and an x for a completed one.

- [x] Start a draft
- [x] Add useful examples
- [ ] Share the finished document

Supported. Checkboxes in the preview are read-only; edit the source to change them.

Strikethrough

Wrap text in two tildes to mark it as removed while keeping it readable. This is useful for small corrections or a change in plans.

Meet at ~~nine~~ ten.
~~Old approach~~ New approach.

Supported in this workspace.

Automatic links

Some Markdown processors recognize a written web address without explicit link syntax. Explicit links with descriptive text are still the most portable choice.

https://example.com

[Project homepage](https://example.com)

`https://example.com`

Bare web URLs are supported. Wrap a URL in backticks to display it as code.

Footnotes

In processors that support footnotes, add a label in square brackets beginning with a caret. Put the note text in a matching definition.

A brief observation.[^field-note]

[^field-note]: Recorded during the afternoon session.

Reference only. Footnotes are not rendered by this workspace.

Custom heading IDs

Some publishing systems let you attach a chosen ID to a heading, which makes links to that section easier to maintain. The notation varies between processors.

### Field notes {#field-notes}

[Jump to field notes](#field-notes)

This workspace generates an ID for every heading automatically from its text (with a numeric suffix for duplicates), so a link like [Jump to field notes](#field-notes) resolves. The explicit {#custom-id} override notation shown above is not supported.

Definition lists

A definition list pairs a term with its explanation. In supporting processors, put the term on one line and start the definition with a colon on the next.

Markdown
: A plain-text format for writing structured documents.

Renderer
: A tool that turns markup into formatted output.

Reference only. Definition lists are not supported by this workspace.

Highlights, subscript & superscript

These extensions are convenient, but support is inconsistent. Check the documentation for the Markdown processor that will publish your document.

==Highlighted text==
H~2~O
x^2^

Reference only. These shorthand extensions are not supported by this workspace. Safe inline HTML such as <sub> and <sup> can be used instead.

Emoji

You can write Unicode emoji directly in a Markdown document. Some tools also expand colon-delimited shortcodes into emoji; that expansion is a feature of the tool.

A new idea 💡

:bulb:

Unicode emoji display in the browser. Shortcodes are not expanded; PDF font coverage may omit emoji.