def detect_headline(article, page, ocr_engine):
    tb = article.get("title_block")
    if tb:
        text, _ = ocr_engine.extract_text(page, _xywh(tb["bbox"]), page["native_words"])
        return text.strip().split("\n")[0]
    # Fallback: largest-font text block
    # font size ~ block height / line count
    candidates = sorted(article["blocks"], key=lambda b: b["bbox"][3]-b["bbox"][1], reverse=True)
    if candidates:
        text, _ = ocr_engine.extract_text(page, _xywh(candidates[0]["bbox"]), page["native_words"])
        return text.strip().split("\n")[0]
    return ""

def _xywh(box):
    return [box[0], box[1], box[2]-box[0], box[3]-box[1]]