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

**Bold text**
*Italic text*
***Bold and italic text***
~~Strikethrough text~~

This is line one.
This is still line one without line break.

This is a new paragraph.

This is line one again.  
This is line two with line break (use two spaces at end of previous line).

- Item 1
- Item 2
  - Nested item 2.1
  - Nested item 2.2
- Item 3

1. First item
2. Second item
   1. Nested item 2.1
   2. Nested item 2.2
3. Third item

> This is a blockquote
> 
> > This is a nested blockquote

---

[Link text](URL)
[Link with title](URL "Title")
<https://automatic-link.com>

[Reference link][ref]

[ref]: https://example.com

![Alt text](URL)
![Alt text](URL "Optional title")

![Alt text][image-id]

[image-id]: URL

Use `code` in a sentence

```
Code block
without syntax highlighting
```

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

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

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

| Left-aligned | Center-aligned | Right-aligned |
|:-------------|:--------------:|---------------:|
| Cell 1       | Cell 2         | Cell 3         |
| Cell 4       | Cell 5         | Cell 6         |

- [x] Completed task
- [ ] Uncompleted task
- [ ] \(Parentheses) escaped with backslash

@username

#123
username/repository#123

:emoji_name:
:smile: :heart: :thumbsup:

```mermaid
graph TD
    A[Start] --> B{Decision}
    B -->|Yes| C[Do Something]
    B -->|No| D[Do Something Else]
    C --> E[End]
    D --> E
```

```mermaid
graph LR
    A[Rectangle] --> B(Rounded Rectangle)
    B --> C{Decision}
    C -->|One| D[Result 1]
    C -->|Two| E[Result 2]
```

```mermaid
sequenceDiagram
    participant Alice
    participant Bob
    Alice->>Bob: Hello Bob, how are you?
    Bob-->>Alice: I am good thanks!
```

```mermaid
classDiagram
    Animal <|-- Duck
    Animal <|-- Fish
    Animal <|-- Zebra
    Animal : +int age
    Animal : +String gender
    Animal: +isMammal()
    Animal: +mate()
    class Duck{
      +String beakColor
      +swim()
      +quack()
    }
```

```mermaid
gantt
    title A Gantt Diagram
    dateFormat  YYYY-MM-DD
    section Section
    A task           :a1, 2014-01-01, 30d
    Another task     :after a1, 20d
```

Here's a sentence with a footnote[^1].

[^1]: This is the footnote content.

Term
: Definition

\*This text is not in italics\*
\# This is not a heading

<details>
  <summary>Click to expand</summary>
  
  Expanded content goes here...
  
  Note: Empty line after summary tag is required.
</details>