import fitz  # PyMuPDF

LETTER_WIDTH = 792      # 8.5 inches
LETTER_HEIGHT = 612     # 11 inches
BOTTOM_MARGIN = 60

def adjust_layout(input_path, output_path, shift_amount):
    doc = fitz.open(input_path)
    new_doc = fitz.open()

    for page in doc:
        rect = page.rect

        # Keep original width, enforce standard height
        new_rect = fitz.Rect(0, 0, LETTER_WIDTH, LETTER_HEIGHT)
        new_page = new_doc.new_page(width=new_rect.width, height=new_rect.height)

        # Shift original content down by shift_amount
        # Clip it back to fit on a Letter-sized page
        content_rect = fitz.Rect(0, shift_amount, rect.width, rect.height + shift_amount - BOTTOM_MARGIN)

        new_page.show_pdf_page(content_rect, doc, page.number)

    new_doc.save(output_path)
    new_doc.close()
    doc.close()