```python
from fractions import Fraction

def combine_fractions(parts: list[str]) -> str:
    if not parts:
        raise ValueError("Input list cannot be empty")
    
    total = Fraction(0)
    for part in parts:
        try:
            fraction = Fraction(part)
            total += fraction
        except (ValueError, TypeError):
            raise ValueError(f"Invalid fraction format: {part}")
    
    return str(total)
```