"""Extracts the content following the 'boxed' keyword from a given string.

This function processes a string to extract the content that appears after the 'boxed' keyword. The extraction handles two main cases:
1. If the content is enclosed in curly braces `{}`, it extracts the entire content within the outermost braces, including any nested braces.
2. If the content is not enclosed in curly braces, it extracts the content up to the first occurrence of the dollar sign `$` or the end of the string, whichever comes first.

Args:
    pred_str (str): The input string containing the 'boxed' keyword and the content to be extracted.

Returns:
    str: The extracted content following the 'boxed' keyword. Returns an empty string if no content is found.
"""
You should write code starting with:
def find_box(pred_str: str) -> str:
    pass

