# Hello, World!
Sample post for testing purposes.
**Bold text**
_Italic text_
~~Strikethrough text~~
`Inline code`
[example.com](https://example.com)
> Done is better than perfect.
## List
- unordered list item 1
- unordered list item 2
- unordered list item 2.1
- unordered list item 2.2
1. ordered list item 1
2. ordered list item 2
1. ordered list item 2.1
2. ordered list item 2.2
## Code
Inline code: `print("Hello, World!")`
```python
def hello_world():
print("Hello, World!")
```
```rust
fn main() {
println!("Hello, World!");
}
```
```javascript
const helloWorld = () => {
console.log("Hello, World!");
};
```
## Math
Inline math: $e^{i\pi} + 1 = 0$
Block math:
$$
\forall \epsilon > 0, \exists \delta > 0
~~\mathrm{s.t.}~~
0 < |x - a| < \delta \implies |f(x) - b| < \epsilon
$$
## Image
![alt text](./icon.webp)
`![alt text](./icon.webp)`:
<img src="./icon.webp" alt="alt text" width="200" />
`<img src="./icon.webp" alt="alt text" width="200" />`:
## Heading 2
### Heading 3
#### Heading 4