def compact_blank_lines(text: str) -> str:
    lines = [line.rstrip() for line in text.splitlines()]
    out, prev_blank = [], False
    for ln in lines:
        blank = (ln.strip() == "")
        if blank and prev_blank:
            continue
        out.append("" if blank else ln)
        prev_blank = blank
    return "\n".join(out)