# Markdown Quick Reference

*Headings, links, images, code blocks, tables*

> Source: CommonMark Spec (commonmark.org) · MIT

## Headings

```
# Heading 1
## Heading 2
### Heading 3
#### Heading 4
##### Heading 5
###### Heading 6
```

## Emphasis

### Bold & Italic

| Command | Description |
|---------|-------------|
| `*italic* or _italic_` | Italic text |
| `**bold** or __bold__` | Bold text |
| `***bold italic***` | Bold and italic |
| `~~strikethrough~~` | Strikethrough (GFM) |

## Lists

### Unordered Lists

```
- Item one
- Item two
  - Nested item
  - Another nested
- Item three
```

### Ordered Lists

```
1. First item
2. Second item
   1. Nested ordered
   2. Another nested
3. Third item
```

## Links & Images

| Command | Description |
|---------|-------------|
| `[text](url)` | Inline link |
| `[text](url "title")` | Link with hover title |
| `[ref][id] / [id]: url` | Reference-style link |
| `<https://example.com>` | Autolink |
| `![alt](image.png)` | Image |
| `![alt](img "title")` | Image with title |
| `[![alt](img)](url)` | Linked image |

## Code

### Inline & Fenced Blocks

```
Use `inline code` in a sentence.

```python
def greet(name):
    return f"Hello, {name}!"
```

```javascript
const greet = (name) => `Hello, ${name}!`;
```
```

*Specify language after ``` for syntax highlighting*

### Indented Code Block

```
Indent 4 spaces
for a code block
(no syntax highlighting)
```

## Blockquotes

```
> This is a blockquote.
>
> It can span multiple paragraphs.

> Nested blockquotes:
>> Second level
>>> Third level
```

## Tables (GFM)

```
| Left   | Center  | Right  |
|--------|:-------:|-------:|
| cell 1 | cell 2  | cell 3 |
| cell 4 | cell 5  | cell 6 |
```

*: controls alignment -- left (default), center, right*

## Task Lists (GFM)

```
- [x] Completed task
- [ ] Incomplete task
- [ ] Another to-do
```

## Horizontal Rules

```
---
***
___
```

*Three or more hyphens, asterisks, or underscores*

## Escaping

### Backslash Escapes

```
\*not italic\*
\# not a heading
\[not a link\]
```

### Escapable Characters

| Command | Description |
|---------|-------------|
| `\  `  *  _` | Backslash, backtick, asterisk, underscore |
| `{}  []  ()` | Braces, brackets, parentheses |
| `#  +  -  .` | Hash, plus, hyphen, period |
| `!  \|` | Exclamation, pipe |