Universal Markdown Cheat Sheet

ATX Headings (H1 to H6)

# Heading 1 (Document Title)
## Heading 2 (Major Section)
### Heading 3 (Subsection)
#### Heading 4
##### Heading 5
###### Heading 6

Setext Headings (H1 & H2 Underlines)

Heading 1 Title
===============

Heading 2 Section
-----------------

Bold, Italic & Strikethrough

**Bold text** or __Bold text__
*Italic text* or _Italic text_
***Bold and italic*** or ___Bold and italic___
~~Strikethrough text~~
==Highlighted mark==

Subscript & Superscript

Water formula: H~2~O
Exponential math: X^2^ + Y^2^ = Z^2^

Line Breaks & Horizontal Rules

First line with two trailing spaces  
Second line directly below

---
***
___

Unordered Bullet Lists

- Top-level item alpha
- Top-level item beta
  - Sub-item nested with 2 spaces
  - Sub-item 2
    - Deeply nested level 3
* Alternative bullet with asterisk
+ Alternative bullet with plus

Ordered Numbered Lists

1. First sequential step
2. Second sequential step
3. Third sequential step
   1. Sub-step A (indented 3 spaces)
   2. Sub-step B
5. Non-sequential (renders as step 4 automatically)

Interactive GFM Task Lists (Checkboxes)

- [x] Completed milestone or deliverable
- [x] Verified unit tests & benchmarks
- [ ] Pending code review approval
- [ ] Deploy to production cluster

Definition Lists

Markdown
: A lightweight markup language with plain text formatting syntax.

GFM
: GitHub Flavored Markdown specification adding tables, task lists, and strikethrough.

Column Alignment (Left, Center, Right)

| Feature | Alignment | Priority | Status |
| :--- | :---: | ---: | :--- |
| Table Headers | Left | 1 | Active |
| Centered Numbers | Center | 250 | In Review |
| Currency / Right | Right | $1,299.00 | Complete |

Formatting Inside Table Cells

| Package | Version | Notes |
| :--- | :--- | :--- |
| **Turbopack** | `v15.0` | [Release Docs](https://nextjs.org) |
| *Tailwind* | `v4.0` | Line break with <br/> tag |
| `mdconverter` | **v2.5** | Escaped pipe: \| character |

Fenced Code Blocks with Language Tags

```typescript
interface UserProfile {
  id: string;
  name: string;
  role: 'admin' | 'developer';
  active: boolean;
}

export const adminUser: UserProfile = {
  id: 'usr_101',
  name: 'Alex Vance',
  role: 'admin',
  active: true,
};
```

Diff Code Blocks (Added / Deleted)

```diff
- const legacyServer = "http://api.old.com";
+ const modernEngine = "https://mdconverter.net/api";
  const timeoutMs = 5000;
```

Inline Code & Escaping Backticks

Use the `npm run build` command to compile.
To show backticks inside code: ``` `code with backticks` ```

GitHub Alert Callout Admonitions

> [!NOTE]
> Highlights essential background information or contextual details.

> [!TIP]
> Helpful advice or best practices to optimize performance.

> [!IMPORTANT]
> Crucial information required for users to succeed.

> [!WARNING]
> Critical actions requiring attention to avoid errors or breaking changes.

> [!CAUTION]
> High-risk alerts regarding potential data loss or security issues.

Nested & Multi-paragraph Blockquotes

> "Simplicity is prerequisite for reliability."
>
> — Edsger W. Dijkstra
>> Nested level 2 quotation
>>> Deeply nested citation

Hyperlinks (Inline, Tooltip & Reference)

[Standard Link](https://mdconverter.net)
[Link with Hover Title](https://mdconverter.net "Universal Converter")
[Internal Anchor Jump](#tables)
<https://mdconverter.net> (Autolink)
<contact@mdconverter.net> (Email autolink)

Reference link: [Official Website][site-ref]

[site-ref]: https://mdconverter.net "Reference Definition"

Images, Badges & Clickable Image Links

![Alt Text Description](https://images.unsplash.com/photo-1555066931-4365d14bab8c?w=800 "Optional Title")

[![Build Status](https://img.shields.io/badge/build-passing-brightgreen.svg)](https://mdconverter.net)

<img src="https://example.com/logo.png" width="120" alt="Logo with custom width" />

Footnotes & Bibliographic Citations

Modern browsers execute WebAssembly with near-native speed.[^1]
Client-side processing guarantees zero cloud leaks.[^privacy]

[^1]: WebAssembly Core Specification 2.0 (W3C).
[^privacy]: MDConverter Privacy Guarantee (2026).

Inline Mathematical Expressions

The mass-energy equivalence formula is $E = mc^2$.
Euler's identity: $e^{i\pi} + 1 = 0$.
Standard deviation: $\sigma = \sqrt{\frac{1}{N} \sum_{i=1}^{N} (x_i - \mu)^2}$

Block Mathematical Equations & Matrices

$$
\int_{-\infty}^{\infty} e^{-x^2} dx = \sqrt{\pi}
$$

$$
\begin{pmatrix}
a & b \\
c & d
\end{pmatrix}
\begin{pmatrix}
x \\
y
\end{pmatrix}
=
\begin{pmatrix}
ax + by \\
cx + dy
\end{pmatrix}
$$

Flowcharts & Architecture Diagrams

```mermaid
graph TD
    A[Markdown Input] --> B{AST Parser}
    B -->|DOCX| C[OpenXML Builder]
    B -->|PDF| D[Vector Print Engine]
    B -->|HTML| E[Syntax Highlighted DOM]
    C --> F[100% Client-Side Download]
    D --> F
    E --> F
```

Sequence & Interaction Diagrams

```mermaid
sequenceDiagram
    autonumber
    actor User
    participant Browser as Client Browser
    participant Worker as Web Worker Engine
    User->>Browser: Drops .docx / .md file
    Browser->>Worker: Parse in-memory ArrayBuffer
    Worker-->>Browser: Return GFM Markdown AST
    Browser-->>User: Display converted document (15ms)
```

Collapsible Accordion Details

<details>
  <summary><strong>Click to view Technical Implementation Details</strong></summary>

  This content is hidden by default and expands on click:
  - Sub-process 1: Lexical tokenization
  - Sub-process 2: AST transformation
  - Sub-process 3: Output serialization
</details>

Keyboard Keys, Mark & Abbreviations

Press <kbd>Ctrl</kbd> + <kbd>K</kbd> to open Command Palette.
Press <kbd>⌘</kbd> + <kbd>Shift</kbd> + <kbd>P</kbd> on macOS.
Important text: <mark>Highlight with mark tag</mark>.
Organization: <abbr title="World Wide Web Consortium">W3C</abbr>

YAML Frontmatter (Jekyll / Next.js / Astro)

---
title: "Enterprise Document Specification"
slug: "enterprise-doc-spec"
version: 3.2.0
author: "MDConverter Team"
isPublished: true
tags:
  - markdown
  - documentation
  - security
---
# Document Body Begins Here
The frontmatter metadata above is parsed cleanly into structured JSON.