# Introduction
This document demonstrates the LaTeX CSSClass styling.
## Mathematical Equations
$E = mc^2$
$\int_{-\infty}^{\infty} e^{-x^2} dx = \sqrt{\pi}$
## Data Table
| Variable | Value | Unit |
|----------|-------|------|
| Speed of Light | 299,792,458 | m/s |
| Planck Constant | 6.626 × 10⁻³⁴ | J⋅s |
## Code Example
```python
def calculate_energy(mass, c=299792458):
return mass * c**2
```