Complete Markdown Guide 2024

# H1 Header
## H2 Header
### H3 Header
#### H4 Header
##### H5 Header
###### H6 Header

**Bold text** or __Bold text__
*Italic text* or _Italic text_
***Bold and italic*** or ___Bold and italic___
~~Strikethrough text~~
`Inline code`

Unordered lists:
- Item 1
- Item 2
  - Nested item
  - Another nested item
- Item 3

Ordered lists:
1. First item
2. Second item
   1. Nested ordered item
   2. Another nested item
3. Third item

[Link text](https://example.com)
[Link with title](https://example.com "Title text")

![Alt text](image.jpg)
![Alt text](image.jpg "Image title")

```javascript
function helloWorld() {
    console.log("Hello, World!");
}
```

```python
def hello_world():
    print("Hello, World!")
```

> This is a blockquote
> 
> Multiple paragraphs in blockquotes
> 
> > Nested blockquotes are also possible

| Header 1 | Header 2 | Header 3 |
|----------|----------|----------|
| Cell 1   | Cell 2   | Cell 3   |
| Cell 4   | Cell 5   | Cell 6   |

Alignment:
| Left | Center | Right |
|:-----|:------:|------:|
| L1   |   C1   |    R1 |
| L2   |   C2   |    R2 |

- [x] Completed task
- [ ] Incomplete task
- [x] Another completed task
  - [ ] Nested incomplete task
  - [x] Nested completed task

```javascript
// JavaScript syntax highlighting
const app = express();
app.get('/', (req, res) => {
  res.send('Hello World!');
});
```

```css
/* CSS syntax highlighting */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}
```