def create_main_pdf(markdown_text):
    buffer = io.BytesIO()
    doc = SimpleDocTemplate(
        buffer, 
        pagesize=(A4[1], A4[0]),  # Landscape A4: 841.89 x 595.27 points
        leftMargin=36,
        rightMargin=36,
        topMargin=36,
        bottomMargin=36
    )
    
    styles = getSampleStyleSheet()
    story = []
    
    page_height = A4[0] - 72
    title_height = 20
    spacer_height = 10
    available_content_height = page_height - title_height - spacer_height
    
    # Process columns first
    left_column, right_column = markdown_to_pdf_content(markdown_text)
    
    # Calculate total items by explicitly handling the unpacking
    total_items = 0
    for col in (left_column, right_column):
        for item in col:
            if isinstance(item, list):
                main_item, sub_items = item  # Unpack here
                total_items += 1 + len(sub_items)
            else:
                total_items += 1
    
    # Dynamic font sizes
    base_font_size = max(6, min(11, 200 / total_items))
    item_font_size = base_font_size
    subitem_font_size = base_font_size * 0.9
    section_font_size = base_font_size * 1.2
    
    # Create custom styles
    title_style = styles['Heading1']
    title_style.textColor = colors.darkblue
    title_style.alignment = 1
    title_style.fontSize = min(16, base_font_size * 1.5)
    
    section_style = ParagraphStyle(
        'SectionStyle',
        parent=styles['Heading2'],
        textColor=colors.darkblue,
        fontSize=section_font_size,
        leading=section_font_size * 1.2,
        spaceAfter=2
    )
    
    item_style = ParagraphStyle(
        'ItemStyle',
        parent=styles['Normal'],
        fontSize=item_font_size,
        leading=item_font_size * 1.2,
        fontName='Helvetica-Bold',
        spaceAfter=1
    )
    
    subitem_style = ParagraphStyle(
        'SubItemStyle',
        parent=styles['Normal'],
        fontSize=subitem_font_size,
        leading=subitem_font_size * 1.2,
        leftIndent=10,
        spaceAfter=1
    )
    
    # Add title
    story.append(Paragraph("Cutting-Edge ML Outline (ReportLab)", title_style))
    story.append(Spacer(1, spacer_height))
    
    # Prepare data for table
    left_cells = []
    for item in left_column:
        if isinstance(item, str) and item.startswith('<b>'):
            text = item.replace('<b>', '').replace('</b>', '')
            left_cells.append(Paragraph(text, section_style))
        elif isinstance(item, list):
            main_item, sub_items = item
            left_cells.append(Paragraph(main_item, item_style))
            for sub_item in sub_items:
                left_cells.append(Paragraph(sub_item, subitem_style))
        else:
            left_cells.append(Paragraph(item, item_style))
    
    right_cells = []
    for item in right_column:
        if isinstance(item, str) and item.startswith('<b>'):
            text = item.replace('<b>', '').replace('</b>', '')
            right_cells.append(Paragraph(text, section_style))
        elif isinstance(item, list):
            main_item, sub_items = item
            right_cells.append(Paragraph(main_item, item_style))
            for sub_item in sub_items:
                right_cells.append(Paragraph(sub_item, subitem_style))
        else:
            right_cells.append(Paragraph(item, item_style))
    
    # Make columns equal length
    max_cells = max(len(left_cells), len(right_cells))
    left_cells.extend([""] * (max_cells - len(left_cells)))
    right_cells.extend([""] * (max_cells - len(right_cells)))
    
    # Create table data
    table_data = list(zip(left_cells, right_cells))
    
    # Calculate column widths
    col_width = (A4[1] - 72) / 2.0
    
    # Create and style table
    table = Table(table_data, colWidths=[col_width, col_width], hAlign='CENTER')
    table.setStyle(TableStyle([
        ('VALIGN', (0, 0), (-1, -1), 'TOP'),
        ('ALIGN', (0, 0), (-1, -1), 'LEFT'),
        ('BACKGROUND', (0, 0), (-1, -1), colors.white),
        ('GRID', (0, 0), (-1, -1), 0, colors.white),
        ('LINEAFTER', (0, 0), (0, -1), 0.5, colors.grey),
        ('LEFTPADDING', (0, 0), (-1, -1), 2),
        ('RIGHTPADDING', (0, 0), (-1, -1), 2),
        ('TOPPADDING', (0, 0), (-1, -1), 1),
        ('BOTTOMPADDING', (0, 0), (-1, -1), 1),
    ]))
    
    story.append(table)
    doc.build(story)
    buffer.seek(0)
    return buffer.getvalue()