Case reversal in a string

You need to write a function that takes a string and returns a new string where each alphabetic character is replaced with the character of the opposite case: lowercase letters become uppercase, and uppercase letters become lowercase. All other characters (digits, spaces, punctuation, etc.) are left unchanged.

Example

def toggle_case(text: str) -> str:
    # implementation of the function
    pass

Requirements

• The function should operate in O(n) time, where n is the length of the input string.
• Do not use built-in methods like swapcase (or their equivalents) from standard libraries.
• Preserve the original order of characters.
• Handle Unicode characters correctly, if the language allows.