from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.units import cm
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, PageBreak, KeepTogether
)
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
import os

OUTPUT = "/tmp/workspace/nutritional-disorders/Nutritional_Disorders_Summary.pdf"

# ---------- Colour palette ----------
DARK_BLUE   = colors.HexColor("#1A3A5C")
MID_BLUE    = colors.HexColor("#2E6DA4")
LIGHT_BLUE  = colors.HexColor("#D6E8F7")
ACCENT      = colors.HexColor("#E8720C")
GREEN       = colors.HexColor("#2E7D32")
LIGHT_GREEN = colors.HexColor("#E8F5E9")
GOLD        = colors.HexColor("#F5A623")
LIGHT_GREY  = colors.HexColor("#F4F6F8")
MID_GREY    = colors.HexColor("#7F8C8D")
RED_SOFT    = colors.HexColor("#C0392B")
TEAL        = colors.HexColor("#00796B")
LIGHT_TEAL  = colors.HexColor("#E0F2F1")

# ---------- Styles ----------
styles = getSampleStyleSheet()

def S(name, **kw):
    return ParagraphStyle(name, **kw)

TITLE_STYLE = S("DocTitle",
    fontSize=26, fontName="Helvetica-Bold",
    textColor=colors.white, alignment=TA_CENTER,
    spaceAfter=6, leading=32)

SUBTITLE_STYLE = S("DocSubtitle",
    fontSize=13, fontName="Helvetica",
    textColor=colors.HexColor("#CCE5FF"), alignment=TA_CENTER,
    spaceAfter=4, leading=18)

META_STYLE = S("Meta",
    fontSize=10, fontName="Helvetica-Oblique",
    textColor=colors.HexColor("#B0C4DE"), alignment=TA_CENTER,
    spaceAfter=2)

SEC_HEADER = S("SectionHeader",
    fontSize=15, fontName="Helvetica-Bold",
    textColor=colors.white, alignment=TA_LEFT,
    leftIndent=8, spaceAfter=0, spaceBefore=0, leading=20)

SUBSEC_HEADER = S("SubSecHeader",
    fontSize=12, fontName="Helvetica-Bold",
    textColor=DARK_BLUE, spaceAfter=4, spaceBefore=8, leading=16)

BODY = S("Body",
    fontSize=10, fontName="Helvetica",
    textColor=colors.HexColor("#2C3E50"),
    alignment=TA_JUSTIFY, spaceAfter=5, spaceBefore=2, leading=14)

BULLET = S("Bullet",
    fontSize=10, fontName="Helvetica",
    textColor=colors.HexColor("#2C3E50"),
    leftIndent=16, bulletIndent=4,
    spaceAfter=3, spaceBefore=1, leading=13,
    bulletText="\u2022")

BOLD_INLINE = S("BoldInline",
    fontSize=10, fontName="Helvetica-Bold",
    textColor=DARK_BLUE)

CAPTION = S("Caption",
    fontSize=8, fontName="Helvetica-Oblique",
    textColor=MID_GREY, alignment=TA_CENTER, spaceAfter=4)

BOX_TEXT = S("BoxText",
    fontSize=10, fontName="Helvetica",
    textColor=colors.HexColor("#1B4332"),
    leftIndent=6, spaceAfter=3, leading=14)

BOX_TITLE = S("BoxTitle",
    fontSize=11, fontName="Helvetica-Bold",
    textColor=GREEN, spaceAfter=5, leading=15)

PREVENTION_TEXT = S("PrevText",
    fontSize=10, fontName="Helvetica",
    textColor=colors.HexColor("#1A237E"),
    leftIndent=6, spaceAfter=3, leading=14)

TABLE_HEADER = S("TableHeader",
    fontSize=10, fontName="Helvetica-Bold",
    textColor=colors.white, alignment=TA_CENTER, leading=13)

TABLE_CELL = S("TableCell",
    fontSize=9, fontName="Helvetica",
    textColor=colors.HexColor("#2C3E50"),
    alignment=TA_LEFT, leading=12, spaceAfter=2)

TABLE_CELL_C = S("TableCellC",
    fontSize=9, fontName="Helvetica",
    textColor=colors.HexColor("#2C3E50"),
    alignment=TA_CENTER, leading=12)

# ============================================================
# Helper: coloured section banner
# ============================================================
def section_banner(title, color=DARK_BLUE):
    data = [[Paragraph(title, SEC_HEADER)]]
    t = Table(data, colWidths=[17*cm])
    t.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), color),
        ("TOPPADDING",    (0,0), (-1,-1), 8),
        ("BOTTOMPADDING", (0,0), (-1,-1), 8),
        ("LEFTPADDING",   (0,0), (-1,-1), 10),
        ("ROUNDEDCORNERS", [6, 6, 6, 6]),
    ]))
    return t

def subheading(text, color=MID_BLUE):
    return Paragraph(f'<font color="#{color.hexval()[2:]}"><b>{text}</b></font>', SUBSEC_HEADER)

def para(text):
    return Paragraph(text, BODY)

def bullet(text):
    return Paragraph(f"<bullet>\u2022</bullet> {text}", BULLET)

def spacer(h=0.25):
    return Spacer(1, h*cm)

def hr(color=LIGHT_BLUE, thickness=1.5):
    return HRFlowable(width="100%", thickness=thickness, color=color, spaceAfter=4, spaceBefore=4)

def green_box(title, items):
    """A bordered prevention strategy box."""
    content = [Paragraph(title, BOX_TITLE)]
    for item in items:
        content.append(Paragraph(f"\u2714  {item}", BOX_TEXT))
    data = [[content]]
    t = Table(data, colWidths=[17*cm])
    t.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,-1), LIGHT_GREEN),
        ("BOX",           (0,0), (-1,-1), 1.5, GREEN),
        ("TOPPADDING",    (0,0), (-1,-1), 10),
        ("BOTTOMPADDING", (0,0), (-1,-1), 10),
        ("LEFTPADDING",   (0,0), (-1,-1), 12),
        ("RIGHTPADDING",  (0,0), (-1,-1), 10),
    ]))
    return t

def blue_box(title, items):
    """A bordered key facts box."""
    content = [Paragraph(title, S("BT2", fontSize=11, fontName="Helvetica-Bold", textColor=MID_BLUE, spaceAfter=5))]
    for item in items:
        content.append(Paragraph(f"\u25B6  {item}", PREVENTION_TEXT))
    data = [[content]]
    t = Table(data, colWidths=[17*cm])
    t.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,-1), LIGHT_BLUE),
        ("BOX",           (0,0), (-1,-1), 1.5, MID_BLUE),
        ("TOPPADDING",    (0,0), (-1,-1), 10),
        ("BOTTOMPADDING", (0,0), (-1,-1), 10),
        ("LEFTPADDING",   (0,0), (-1,-1), 12),
        ("RIGHTPADDING",  (0,0), (-1,-1), 10),
    ]))
    return t

# ============================================================
# Build the document
# ============================================================
doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=2*cm, rightMargin=2*cm,
    topMargin=2*cm, bottomMargin=2.2*cm,
    title="Key Nutritional Disorders & Prevention Strategies",
    author="Orris Medical Library",
    subject="Nutritional Pathology Summary for Medical Students"
)

story = []

# -------- COVER --------
cover_data = [[
    Paragraph("KEY NUTRITIONAL DISORDERS", TITLE_STYLE),
    Paragraph("& Prevention Strategies", SUBTITLE_STYLE),
    Paragraph("A Structured Summary for Medical Students", META_STYLE),
    Spacer(1, 0.3*cm),
    Paragraph("Based on Robbins & Kumar Pathology | Park's PSM | Lippincott Biochemistry | Harrison's Medicine", META_STYLE),
    Spacer(1, 0.15*cm),
    Paragraph("July 2026", META_STYLE),
]]
cover_table = Table(cover_data, colWidths=[17*cm])
cover_table.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,-1), DARK_BLUE),
    ("TOPPADDING",    (0,0), (-1,-1), 24),
    ("BOTTOMPADDING", (0,0), (-1,-1), 24),
    ("LEFTPADDING",   (0,0), (-1,-1), 18),
    ("RIGHTPADDING",  (0,0), (-1,-1), 18),
]))
story.append(cover_table)
story.append(spacer(0.5))

# -------- INTRO --------
story.append(section_banner("INTRODUCTION"))
story.append(spacer(0.2))
story.append(para(
    "Nutritional disorders span two extremes of the dietary spectrum - "
    "<b>undernutrition</b> and <b>overnutrition</b> - both contributing enormous disease burden globally. "
    "These disorders are preventable, often treatable, and intimately linked to social determinants of health "
    "including poverty, food insecurity, education, and access to healthcare."
))
story.append(para(
    "This document provides a structured overview of the major nutritional disorders encountered in clinical "
    "pathology and preventive medicine, including their aetiology, pathophysiology, clinical features, "
    "morphological findings, and prevention strategies - aligned with the curricula of Robbins, Harsh Mohan, "
    "Park's PSM, and Lippincott Biochemistry."
))
story.append(spacer(0.3))

# -------- OVERVIEW TABLE --------
story.append(section_banner("OVERVIEW: SPECTRUM OF NUTRITIONAL DISORDERS", MID_BLUE))
story.append(spacer(0.2))

ov_header = [
    Paragraph("Disorder", TABLE_HEADER),
    Paragraph("Type", TABLE_HEADER),
    Paragraph("Primary Nutrient Deficit", TABLE_HEADER),
    Paragraph("Key Consequence", TABLE_HEADER),
]
ov_rows = [
    ["Marasmus", "Undernutrition (PEM)", "Calories + Protein", "Severe wasting, no oedema"],
    ["Kwashiorkor", "Undernutrition (PEM)", "Protein (calories spared)", "Oedema, fatty liver, skin changes"],
    ["Vitamin A Deficiency", "Micronutrient", "Retinol (Vitamin A)", "Xerophthalmia, night blindness"],
    ["Iodine Deficiency", "Micronutrient", "Iodine", "Goitre, cretinism, intellectual disability"],
    ["Iron Deficiency Anaemia", "Micronutrient", "Iron (Fe)", "Hypochromic microcytic anaemia"],
    ["Vitamin D Deficiency", "Micronutrient", "Cholecalciferol (Vit D)", "Rickets (children), Osteomalacia (adults)"],
    ["Scurvy", "Micronutrient", "Vitamin C (Ascorbic acid)", "Perifollicular haemorrhages, impaired healing"],
    ["Thiamine Deficiency", "Micronutrient (B1)", "Thiamine (Vit B1)", "Beriberi, Wernicke-Korsakoff"],
    ["Folate / B12 Deficiency", "Micronutrient", "Folate or Cobalamin", "Megaloblastic anaemia, NTDs"],
    ["Obesity", "Overnutrition", "Excess calorie intake", "Metabolic syndrome, T2DM, CVD, cancer"],
]

ov_data = [ov_header]
for i, row in enumerate(ov_rows):
    bg = LIGHT_GREY if i % 2 == 0 else colors.white
    ov_data.append([Paragraph(row[j], TABLE_CELL if j != 0 else
                              S(f"TC{i}", fontSize=9, fontName="Helvetica-Bold", textColor=DARK_BLUE, leading=12))
                    for j in range(4)])

ov_table = Table(ov_data, colWidths=[4.2*cm, 3.5*cm, 4.3*cm, 5*cm])
ov_table.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), DARK_BLUE),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [LIGHT_GREY, colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, MID_BLUE),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#BDC3C7")),
    ("TOPPADDING",    (0,0), (-1,-1), 6),
    ("BOTTOMPADDING", (0,0), (-1,-1), 6),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
]))
story.append(ov_table)
story.append(spacer(0.4))

# ============================================================
# SECTION 1 - PROTEIN-ENERGY MALNUTRITION
# ============================================================
story.append(PageBreak())
story.append(section_banner("1. PROTEIN-ENERGY MALNUTRITION (PEM)", colors.HexColor("#6A1B9A")))
story.append(spacer(0.2))

story.append(para(
    "PEM encompasses a spectrum of deficiency states resulting from inadequate protein and/or caloric intake. "
    "The two polar forms are <b>Marasmus</b> (calorie + protein deficit) and <b>Kwashiorkor</b> "
    "(predominantly protein deficit with relative calorie sparing). A mixed form - <b>Marasmic Kwashiorkor</b> - "
    "is also recognised. PEM predominantly affects children under 5 in low-resource settings."
))
story.append(spacer(0.15))

# Side-by-side comparison table
comp_header = [
    Paragraph("Feature", TABLE_HEADER),
    Paragraph("Marasmus", TABLE_HEADER),
    Paragraph("Kwashiorkor", TABLE_HEADER),
]
comp_rows = [
    ["Primary deficit",     "Calories + protein",                       "Protein (calories relatively preserved)"],
    ["Age of onset",        "Infancy (< 1 year)",                       "Weaning age (1-3 years)"],
    ["Body weight",         "< 60% expected (severe wasting)",          "60-80% expected"],
    ["Oedema",              "Absent",                                   "Present (hypoalbuminaemia)"],
    ["Subcutaneous fat",    "Markedly depleted",                        "May be present"],
    ["Muscle wasting",      "Severe",                                   "Moderate"],
    ["Skin changes",        "Loose, wrinkled skin",                     "Flaky paint / crazy paving dermatosis"],
    ["Hair changes",        "Thin, sparse hair",                        "Flag sign (alternating light/dark bands)"],
    ["Serum albumin",       "Low but relatively maintained",            "Markedly low (< 2.8 g/dL)"],
    ["Fatty liver",         "Absent",                                   "Present (hallmark)"],
    ["Appetite",            "Usually preserved",                        "Often poor"],
    ["Immune function",     "Severely impaired",                        "Severely impaired"],
    ["Prognosis",           "Grave without intervention",               "Worse than marasmus when severe"],
]

comp_data = [comp_header]
for row in comp_rows:
    comp_data.append([
        Paragraph(f"<b>{row[0]}</b>", TABLE_CELL),
        Paragraph(row[1], TABLE_CELL),
        Paragraph(row[2], TABLE_CELL),
    ])

comp_table = Table(comp_data, colWidths=[4.5*cm, 6.1*cm, 6.4*cm])
comp_table.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), colors.HexColor("#6A1B9A")),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [colors.HexColor("#F3E5F5"), colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, colors.HexColor("#7B1FA2")),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#CE93D8")),
    ("TOPPADDING",    (0,0), (-1,-1), 5),
    ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("VALIGN",        (0,0), (-1,-1), "TOP"),
]))
story.append(comp_table)
story.append(spacer(0.25))

story.append(subheading("Pathological Features (Robbins & Kumar)"))
story.append(bullet("Growth failure is universal in both forms"))
story.append(bullet("Kwashiorkor: <b>fatty change in the liver</b> due to decreased apolipoprotein B synthesis, impairing VLDL assembly"))
story.append(bullet("Peripheral oedema in kwashiorkor is caused by <b>hypoalbuminaemia reducing plasma oncotic pressure</b>"))
story.append(bullet("Marasmus: severe atrophy of all organs except brain (brain-sparing effect in early disease)"))
story.append(bullet("Both: thymic and lymphoid atrophy, impaired cell-mediated immunity - increased susceptibility to infection"))
story.append(spacer(0.2))

story.append(green_box(
    "Prevention Strategies - PEM",
    [
        "Promotion and support of exclusive breastfeeding for 6 months",
        "Introduction of diversified complementary foods rich in protein (legumes, eggs, dairy)",
        "Ready-to-use therapeutic food (RUTF) for treatment of severe acute malnutrition",
        "Community-based nutritional surveillance and growth monitoring",
        "Nutrition education programmes targeting mothers and caregivers",
        "Food security policies and social protection programmes for vulnerable populations",
        "WHO/UNICEF Integrated Management of Acute Malnutrition (IMAM) protocol",
    ]
))
story.append(spacer(0.4))

# ============================================================
# SECTION 2 - VITAMIN A DEFICIENCY
# ============================================================
story.append(PageBreak())
story.append(section_banner("2. VITAMIN A DEFICIENCY", colors.HexColor("#E65100")))
story.append(spacer(0.2))

story.append(para(
    "<b>Vitamin A (Retinol)</b> is a fat-soluble vitamin essential for vision (synthesis of rhodopsin), "
    "epithelial integrity, immune function, and embryonic development. It is the "
    "<b>leading preventable cause of childhood blindness</b> worldwide, affecting an estimated "
    "250,000-500,000 children annually, half of whom die within a year of going blind."
))
story.append(spacer(0.15))

story.append(subheading("Aetiology & At-Risk Groups"))
story.append(bullet("Dietary deficiency: inadequate intake of animal products (liver, eggs, dairy) and dark green/orange vegetables"))
story.append(bullet("Fat malabsorption: celiac disease, cystic fibrosis, cholestatic liver disease"))
story.append(bullet("Children 6 months to 5 years in Sub-Saharan Africa and South/Southeast Asia"))
story.append(bullet("Pregnant and lactating women"))
story.append(spacer(0.15))

story.append(subheading("Clinical Manifestations (WHO Classification)"))
ocular_data = [
    [Paragraph("<b>Stage</b>", TABLE_HEADER), Paragraph("<b>Feature</b>", TABLE_HEADER), Paragraph("<b>Reversibility</b>", TABLE_HEADER)],
    [Paragraph("XN", TABLE_CELL_C), Paragraph("Night blindness (nyctalopia) - earliest sign", TABLE_CELL), Paragraph("Reversible", TABLE_CELL_C)],
    [Paragraph("X1A", TABLE_CELL_C), Paragraph("Conjunctival xerosis (dryness)", TABLE_CELL), Paragraph("Reversible", TABLE_CELL_C)],
    [Paragraph("X1B", TABLE_CELL_C), Paragraph("Bitot's spots (foamy triangular patches on bulbar conjunctiva)", TABLE_CELL), Paragraph("Reversible", TABLE_CELL_C)],
    [Paragraph("X2", TABLE_CELL_C), Paragraph("Corneal xerosis", TABLE_CELL), Paragraph("Reversible", TABLE_CELL_C)],
    [Paragraph("X3A", TABLE_CELL_C), Paragraph("Corneal ulceration < 1/3 cornea", TABLE_CELL), Paragraph("Partially reversible", TABLE_CELL_C)],
    [Paragraph("X3B", TABLE_CELL_C), Paragraph("Keratomalacia - corneal liquefaction", TABLE_CELL), Paragraph("<b>Irreversible - blindness</b>", TABLE_CELL_C)],
]
ot = Table(ocular_data, colWidths=[2.5*cm, 10*cm, 4.5*cm])
ot.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), colors.HexColor("#E65100")),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [colors.HexColor("#FFF3E0"), colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, colors.HexColor("#E65100")),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#FFCC80")),
    ("TOPPADDING",    (0,0), (-1,-1), 5), ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 6), ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
]))
story.append(ot)
story.append(spacer(0.15))

story.append(subheading("Systemic Effects"))
story.append(bullet("Squamous metaplasia of respiratory, GI, and urinary tract epithelium - increased infection risk"))
story.append(bullet("Impaired T-cell differentiation and reduced NK cell activity"))
story.append(bullet("Impaired growth in children"))
story.append(bullet("Increased severity of measles and other childhood infections"))
story.append(spacer(0.2))

story.append(green_box(
    "Prevention Strategies - Vitamin A Deficiency",
    [
        "High-dose vitamin A supplementation (100,000-200,000 IU) given to children 6-59 months twice yearly",
        "Vitamin A supplementation to mothers within 6 weeks postpartum in deficient areas",
        "Fortification of commonly consumed foods: sugar, cooking oil, margarine, flour",
        "Promotion of dietary diversification - dark green leafy vegetables, orange/yellow fruits",
        "Golden Rice biofortification programme (in development)",
        "Promotion of exclusive breastfeeding (breast milk is a significant source of vitamin A)",
        "WHO/UNICEF vitamin A supplementation programme in conjunction with childhood immunisation",
    ]
))
story.append(spacer(0.4))

# ============================================================
# SECTION 3 - IODINE DEFICIENCY
# ============================================================
story.append(PageBreak())
story.append(section_banner("3. IODINE DEFICIENCY DISORDERS (IDD)", TEAL))
story.append(spacer(0.2))

story.append(para(
    "Iodine is an essential trace mineral required for synthesis of thyroid hormones (T3 and T4). "
    "Iodine deficiency is the <b>most common preventable cause of intellectual disability worldwide</b>. "
    "It affects an estimated 2 billion people, particularly in mountainous regions and areas distant from the ocean. "
    "The spectrum of iodine deficiency disorders (IDD) includes goitre, hypothyroidism, and cretinism."
))
story.append(spacer(0.15))

story.append(subheading("Spectrum of Iodine Deficiency Disorders"))
idd_data = [
    [Paragraph("Stage / Form", TABLE_HEADER), Paragraph("Population", TABLE_HEADER), Paragraph("Key Features", TABLE_HEADER)],
    [Paragraph("Goitre", TABLE_CELL), Paragraph("All ages", TABLE_CELL), Paragraph("Thyroid enlargement due to TSH-driven hyperplasia; may cause compressive symptoms", TABLE_CELL)],
    [Paragraph("Hypothyroidism", TABLE_CELL), Paragraph("Adults", TABLE_CELL), Paragraph("Fatigue, weight gain, cold intolerance, myxoedema, decreased metabolic rate", TABLE_CELL)],
    [Paragraph("Cretinism (Congenital IDD)", TABLE_CELL), Paragraph("Neonates / infants", TABLE_CELL), Paragraph("Intellectual disability, short stature, coarse facies, protruding tongue, umbilical hernia, deafness", TABLE_CELL)],
    [Paragraph("Subclinical hypothyroidism", TABLE_CELL), Paragraph("Adults", TABLE_CELL), Paragraph("Elevated TSH, normal T4; fatigue, mild cognitive impairment", TABLE_CELL)],
    [Paragraph("Foetal loss / stillbirth", TABLE_CELL), Paragraph("Pregnant women", TABLE_CELL), Paragraph("Severe deficiency in pregnancy leads to miscarriage, preterm birth, stillbirth", TABLE_CELL)],
]
it = Table(idd_data, colWidths=[4.2*cm, 3.8*cm, 9*cm])
it.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), TEAL),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [LIGHT_TEAL, colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, TEAL),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#80CBC4")),
    ("TOPPADDING",    (0,0), (-1,-1), 5), ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 6), ("VALIGN", (0,0), (-1,-1), "TOP"),
]))
story.append(it)
story.append(spacer(0.15))

story.append(subheading("Pathophysiology"))
story.append(bullet("Low iodine intake -> reduced T3/T4 synthesis -> increased TSH secretion by pituitary"))
story.append(bullet("Chronic TSH stimulation causes thyroid follicular cell hyperplasia and colloid accumulation -> goitre"))
story.append(bullet("During pregnancy, foetal T4 depends on maternal iodine; severe deficiency causes irreversible neurological damage"))
story.append(spacer(0.2))

story.append(green_box(
    "Prevention Strategies - Iodine Deficiency",
    [
        "Universal salt iodisation (USI) - most cost-effective intervention; target of 15-40 ppm potassium iodate",
        "Iodine supplementation (oral or intramuscular) in highly deficient areas not yet reached by USI",
        "Iodine supplementation in pregnancy and lactation (WHO recommends 250 mcg/day)",
        "Iodisation of irrigation water in severely deficient regions",
        "Regular monitoring of urinary iodine concentration (UIC) to assess population status",
        "Public education on dietary iodine sources (seafood, dairy, iodised salt)",
    ]
))
story.append(spacer(0.4))

# ============================================================
# SECTION 4 - IRON DEFICIENCY ANAEMIA
# ============================================================
story.append(section_banner("4. IRON DEFICIENCY ANAEMIA (IDA)", colors.HexColor("#B71C1C")))
story.append(spacer(0.2))

story.append(para(
    "<b>Iron deficiency anaemia</b> is the most common nutritional deficiency globally, "
    "affecting over <b>1.6 billion people</b> (WHO). It is particularly prevalent among "
    "preschool children, pregnant women, and women of reproductive age in low-income countries. "
    "Iron deficiency reduces haemoglobin synthesis, resulting in <b>hypochromic microcytic anaemia</b>."
))
story.append(spacer(0.15))

story.append(subheading("Causes"))
story.append(bullet("<b>Inadequate intake:</b> low dietary iron (especially haem iron from animal sources)"))
story.append(bullet("<b>Increased demand:</b> pregnancy, lactation, rapid growth in infancy/adolescence"))
story.append(bullet("<b>Chronic blood loss:</b> menorrhagia, GI bleeding (hookworm, peptic ulcer, colorectal carcinoma)"))
story.append(bullet("<b>Malabsorption:</b> coeliac disease, gastric bypass, achlorhydria"))
story.append(spacer(0.15))

story.append(subheading("Stages of Iron Deficiency"))
stage_data = [
    [Paragraph("Stage", TABLE_HEADER), Paragraph("Iron Stores", TABLE_HEADER), Paragraph("Serum Iron", TABLE_HEADER), Paragraph("TIBC", TABLE_HEADER), Paragraph("Haemoglobin", TABLE_HEADER)],
    ["1 - Pre-latent", "Depleted", "Normal", "Normal", "Normal"],
    ["2 - Latent", "Absent", "Reduced", "Increased", "Normal"],
    ["3 - IDA", "Absent", "Reduced", "Increased", "Reduced"],
]
sd = [[Paragraph(c if isinstance(c, str) else c.text, TABLE_CELL_C if i > 0 else TABLE_CELL) if isinstance(c, str) else c
       for c in row] for i, row in enumerate(stage_data)]
sd[0] = stage_data[0]
for i in range(1, len(stage_data)):
    sd[i] = [Paragraph(c, TABLE_CELL_C) for c in stage_data[i]]

st_t = Table(sd, colWidths=[3.5*cm, 3.4*cm, 3.4*cm, 3.4*cm, 3.3*cm])
st_t.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), colors.HexColor("#B71C1C")),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [colors.HexColor("#FFEBEE"), colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, colors.HexColor("#B71C1C")),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#EF9A9A")),
    ("TOPPADDING",    (0,0), (-1,-1), 5), ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 6), ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
]))
story.append(st_t)
story.append(spacer(0.15))

story.append(subheading("Clinical Features"))
story.append(bullet("General: fatigue, pallor, exertional dyspnoea, palpitations, reduced work capacity"))
story.append(bullet("Epithelial: koilonychia (spoon-shaped nails), angular stomatitis, glossitis, brittle hair/nails"))
story.append(bullet("Neurological: impaired cognitive development in children, poor school performance"))
story.append(bullet("Pica (geophagia): craving for non-food items - a distinctive feature"))
story.append(bullet("Plummer-Vinson syndrome: IDA + oesophageal web + glossitis (rare)"))
story.append(spacer(0.2))

story.append(green_box(
    "Prevention Strategies - Iron Deficiency Anaemia",
    [
        "Food fortification: iron fortification of wheat flour, rice, and staple cereals (WHO-endorsed)",
        "Iron supplementation: daily iron-folic acid tablets in pregnancy; weekly supplements for adolescent girls",
        "Promotion of dietary diversification: haem iron from meat, fish; non-haem iron from legumes and leafy greens",
        "Vitamin C co-ingestion to enhance non-haem iron absorption",
        "Avoidance of inhibitors: limit tea/coffee with meals (tannins reduce absorption)",
        "Control of hookworm and other intestinal parasites (mass deworming programmes)",
        "Delayed cord clamping at birth - increases neonatal iron stores",
        "Promotion of breastfeeding and appropriate weaning with iron-rich foods",
    ]
))
story.append(spacer(0.4))

# ============================================================
# SECTION 5 - VITAMIN D DEFICIENCY
# ============================================================
story.append(PageBreak())
story.append(section_banner("5. VITAMIN D DEFICIENCY (RICKETS / OSTEOMALACIA)", colors.HexColor("#F57F17")))
story.append(spacer(0.2))

story.append(para(
    "<b>Vitamin D</b> is a fat-soluble prohormone synthesised in the skin on exposure to UVB radiation "
    "(cholecalciferol, D3) and obtained from dietary sources. It undergoes hepatic hydroxylation to "
    "25-hydroxyvitamin D [25(OH)D], then renal hydroxylation to the active form "
    "<b>1,25-dihydroxyvitamin D [calcitriol]</b>, which promotes intestinal calcium and phosphate absorption. "
    "Deficiency causes <b>Rickets</b> in children (before growth plate fusion) and "
    "<b>Osteomalacia</b> in adults (defective mineralisation of mature bone)."
))
story.append(spacer(0.15))

story.append(subheading("Clinical Features - Rickets (Children)"))
story.append(bullet("<b>Rachitic rosary</b> - swelling at costochondral junctions creating a 'string of beads'"))
story.append(bullet("<b>Craniotabes</b> - softening and thinning of the skull in infants"))
story.append(bullet("<b>Frontal bossing</b> and delayed fontanelle closure"))
story.append(bullet("<b>Genu varum (bow legs)</b> or genu valgum (knock-knees) - lower limb deformities"))
story.append(bullet("<b>Harrison's sulcus</b> - horizontal groove along the lower chest wall"))
story.append(bullet("Widened wrists and ankles; delayed dentition; growth failure"))
story.append(spacer(0.15))

story.append(subheading("Clinical Features - Osteomalacia (Adults)"))
story.append(bullet("Diffuse bone pain and tenderness, particularly in pelvis, spine, and lower limbs"))
story.append(bullet("Proximal muscle weakness and fatigue"))
story.append(bullet("<b>Looser zones (Milkman fractures)</b> - pseudofractures on X-ray"))
story.append(bullet("Pelvic deformity - may cause obstructed labour in females"))
story.append(spacer(0.15))

story.append(subheading("Laboratory Findings in Vitamin D Deficiency"))
lab_data = [
    [Paragraph("Parameter", TABLE_HEADER), Paragraph("Finding", TABLE_HEADER), Paragraph("Note", TABLE_HEADER)],
    ["Serum 25(OH)D", "< 20 ng/mL (deficiency)", "Gold standard test"],
    ["Serum calcium", "Low or normal", "Secondary hyperparathyroidism maintains Ca"],
    ["Serum phosphate", "Low", "PTH promotes renal phosphate wasting"],
    ["ALP (alkaline phosphatase)", "Elevated", "Reflects active osteoblastic activity"],
    ["PTH", "Elevated (secondary)", "Compensatory response to low Ca"],
    ["Urine calcium", "Low (hypocalciuria)", "Reduced intestinal absorption + renal reabsorption"],
]
ld = [[Paragraph(c, TABLE_CELL if i > 0 else TABLE_HEADER) for c in row] for i, row in enumerate(lab_data)]
ld[0] = [Paragraph(c, TABLE_HEADER) for c in lab_data[0]]

lt = Table(ld, colWidths=[5*cm, 5*cm, 7*cm])
lt.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), colors.HexColor("#F57F17")),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [colors.HexColor("#FFF9C4"), colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, colors.HexColor("#F9A825")),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#FFE082")),
    ("TOPPADDING",    (0,0), (-1,-1), 5), ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 6), ("VALIGN", (0,0), (-1,-1), "TOP"),
]))
story.append(lt)
story.append(spacer(0.2))

story.append(green_box(
    "Prevention Strategies - Vitamin D Deficiency",
    [
        "Adequate sun exposure: 15-30 min of midday sun on face and arms, 2-3 times per week",
        "Dietary sources: oily fish, egg yolk, fortified dairy products and cereals",
        "Vitamin D supplementation: 400 IU/day for infants 0-12 months (all breastfed infants)",
        "600-800 IU/day for adults; 800-2000 IU/day for elderly and high-risk groups",
        "Fortification of milk, margarine, and orange juice with Vitamin D3",
        "Routine screening of high-risk groups: dark-skinned individuals in low-sun areas, veiled women",
        "Supplementation in pregnancy to prevent neonatal rickets",
    ]
))
story.append(spacer(0.4))

# ============================================================
# SECTION 6 - SCURVY
# ============================================================
story.append(section_banner("6. SCURVY (VITAMIN C DEFICIENCY)", colors.HexColor("#1B5E20")))
story.append(spacer(0.2))

story.append(para(
    "<b>Vitamin C (Ascorbic acid)</b> is a water-soluble antioxidant essential for collagen synthesis "
    "(hydroxylation of proline and lysine in collagen), iron absorption, catecholamine synthesis, and "
    "immune function. Scurvy develops after approximately <b>1-3 months</b> of severely deficient intake "
    "(< 10 mg/day). At-risk groups include infants fed only cow's milk, elderly people with restricted diets, "
    "alcoholics, and prisoners."
))
story.append(spacer(0.15))

story.append(subheading("Pathophysiology"))
story.append(bullet("Defective collagen synthesis -> impaired wound healing, weakened blood vessel walls"))
story.append(bullet("Capillary fragility leads to <b>perifollicular haemorrhages</b> (classic sign) and ecchymoses"))
story.append(bullet("Impaired osteoid formation -> periosteal haemorrhages, growth failure in children"))
story.append(spacer(0.15))

story.append(subheading("Clinical Features"))
story.append(bullet("<b>Perifollicular haemorrhages</b> - most characteristic sign; petechiae around hair follicles with coiled (corkscrew) hairs"))
story.append(bullet("<b>Spongy, bleeding gums</b> with gingivitis (only in those with teeth)"))
story.append(bullet("Impaired wound healing and wound dehiscence"))
story.append(bullet("Subperiosteal haemorrhages - painful tender bones, especially in children"))
story.append(bullet("Anaemia (due to poor iron absorption and bleeding)"))
story.append(bullet("'Sabre tibia' and rosary of scorbutic beads at costochondral junctions in children"))
story.append(bullet("Psychological symptoms: irritability, depression"))
story.append(spacer(0.2))

story.append(green_box(
    "Prevention Strategies - Scurvy",
    [
        "Dietary diversification: citrus fruits (lemon, orange, lime), guava, kiwi, bell peppers, strawberries",
        "Minimum dietary requirement: 10 mg/day (prevention); RDA is 65-90 mg/day",
        "Supplementation (500-1000 mg/day) for at-risk groups: elderly, alcoholics, food-restricted individuals",
        "Food fortification programmes in institutional settings (prisons, long-term care facilities)",
        "Antenatal care education on vitamin C-rich food intake",
        "Avoid prolonged cooking of vegetables - destroys vitamin C",
    ]
))
story.append(spacer(0.4))

# ============================================================
# SECTION 7 - THIAMINE / B-VITAMINS
# ============================================================
story.append(PageBreak())
story.append(section_banner("7. B-VITAMIN DEFICIENCIES", colors.HexColor("#004D40")))
story.append(spacer(0.2))

bvit_data = [
    [Paragraph("Vitamin", TABLE_HEADER), Paragraph("Deficiency Syndrome", TABLE_HEADER), Paragraph("Key Clinical Features", TABLE_HEADER), Paragraph("At-Risk Groups", TABLE_HEADER)],
    ["Thiamine (B1)", "Beriberi; Wernicke-Korsakoff", "Wet beriberi: HF, peripheral oedema; Dry beriberi: peripheral neuropathy; Wernicke: ophthalmoplegia, ataxia, confusion; Korsakoff: amnesia", "Alcoholics, extreme diet, gastric bypass"],
    ["Riboflavin (B2)", "Ariboflavinosis", "Angular stomatitis, cheilitis, glossitis (magenta tongue), corneal vascularisation", "Poverty, alcohol, malabsorption"],
    ["Niacin (B3)", "Pellagra", "The 3 Ds: Dermatitis, Diarrhoea, Dementia (+/- Death); Casal's necklace rash", "Maize-based diets (low tryptophan)"],
    ["Pyridoxine (B6)", "B6 deficiency", "Peripheral neuropathy, stomatitis, microcytic anaemia, seizures in neonates", "Alcoholics, INH therapy, malabsorption"],
    ["Folate (B9)", "Megaloblastic anaemia; NTDs", "Macrocytic anaemia; Neural tube defects in foetus (anencephaly, spina bifida)", "Pregnant women, alcoholics, malabsorption"],
    ["Cobalamin (B12)", "Subacute combined degeneration", "Megaloblastic anaemia + subacute combined degeneration of spinal cord (B12-specific), peripheral neuropathy", "Vegans, pernicious anaemia, elderly"],
]

bv = [[Paragraph(c, TABLE_CELL) for c in row] for row in bvit_data]
bv[0] = [Paragraph(c, TABLE_HEADER) for c in bvit_data[0]]

bvt = Table(bv, colWidths=[3*cm, 4*cm, 6*cm, 4*cm])
bvt.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), colors.HexColor("#004D40")),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [LIGHT_TEAL, colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, colors.HexColor("#00695C")),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#80CBC4")),
    ("TOPPADDING",    (0,0), (-1,-1), 5), ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 5), ("VALIGN", (0,0), (-1,-1), "TOP"),
]))
story.append(bvt)
story.append(spacer(0.2))

story.append(green_box(
    "Prevention Strategies - B-Vitamin Deficiencies",
    [
        "Folate: periconceptional folic acid supplementation (0.4-5 mg/day) to prevent neural tube defects",
        "Folate fortification of flour (mandatory in many countries)",
        "Thiamine: adequate dietary intake; supplementation for all patients with alcohol use disorder",
        "Niacin: dietary diversification away from maize monoculture; niacin fortification of staples",
        "B12: supplementation for all vegans and vegetarians; B12 injections for pernicious anaemia",
        "Pyridoxine: prophylactic B6 for patients on isoniazid (INH) therapy for TB",
    ]
))
story.append(spacer(0.4))

# ============================================================
# SECTION 8 - OBESITY
# ============================================================
story.append(section_banner("8. OBESITY & OVERNUTRITION", colors.HexColor("#880E4F")))
story.append(spacer(0.2))

story.append(para(
    "Obesity (BMI >= 30 kg/m²) represents the overnutrition end of the nutritional spectrum and has reached "
    "epidemic proportions globally. The WHO estimates over <b>650 million adults</b> are obese and over "
    "<b>1.9 billion are overweight</b>. Obesity is a major driver of metabolic syndrome, type 2 diabetes, "
    "cardiovascular disease, and multiple cancers."
))
story.append(spacer(0.15))

story.append(subheading("BMI Classification (WHO)"))
bmi_data = [
    [Paragraph("Category", TABLE_HEADER), Paragraph("BMI (kg/m²)", TABLE_HEADER), Paragraph("Health Risk", TABLE_HEADER)],
    ["Underweight", "< 18.5", "Increased (malnutrition)"],
    ["Normal weight", "18.5 - 24.9", "Lowest"],
    ["Overweight", "25.0 - 29.9", "Mildly increased"],
    ["Obese Class I", "30.0 - 34.9", "Moderate"],
    ["Obese Class II", "35.0 - 39.9", "Severe"],
    ["Obese Class III (Morbid)", ">= 40", "Very severe"],
]
bmi_t_data = [[Paragraph(c, TABLE_CELL_C if i > 0 else TABLE_HEADER) for c in row] for i, row in enumerate(bmi_data)]
bmi_t_data[0] = [Paragraph(c, TABLE_HEADER) for c in bmi_data[0]]

bmi_t = Table(bmi_t_data, colWidths=[5.5*cm, 5.5*cm, 6*cm])
bmi_t.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), colors.HexColor("#880E4F")),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [colors.HexColor("#FCE4EC"), colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, colors.HexColor("#AD1457")),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#F48FB1")),
    ("TOPPADDING",    (0,0), (-1,-1), 5), ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 6), ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
]))
story.append(bmi_t)
story.append(spacer(0.15))

story.append(subheading("Health Consequences of Obesity"))
story.append(bullet("<b>Metabolic syndrome</b>: central obesity + insulin resistance + dyslipidaemia + hypertension"))
story.append(bullet("<b>Type 2 diabetes</b>: adipokine dysregulation promotes insulin resistance"))
story.append(bullet("<b>Cardiovascular disease</b>: coronary artery disease, hypertension, stroke, heart failure"))
story.append(bullet("<b>Non-alcoholic fatty liver disease (NAFLD)</b> and its progression to NASH, cirrhosis"))
story.append(bullet("<b>Cancer</b>: increased risk of endometrial, breast, colorectal, oesophageal, renal, pancreatic"))
story.append(bullet("<b>Obstructive sleep apnoea</b> and obesity hypoventilation syndrome"))
story.append(bullet("<b>Osteoarthritis</b>, PCOS, gallstones, and pregnancy complications"))
story.append(spacer(0.2))

story.append(green_box(
    "Prevention Strategies - Obesity",
    [
        "Population-level dietary guidelines: limit ultra-processed foods, added sugars, saturated fats",
        "Promotion of physical activity: WHO recommends 150-300 min/week of moderate-intensity exercise",
        "Sugar-sweetened beverage taxation (proven effective in multiple countries)",
        "Front-of-pack food labelling (traffic light system) to guide consumer choices",
        "Restriction of junk food advertising to children",
        "School-based interventions: healthy canteen policies, physical education",
        "Medical management: behavioural counselling, pharmacotherapy (orlistat, GLP-1 agonists like semaglutide)",
        "Bariatric surgery for BMI >= 40 (or >= 35 with comorbidities)",
    ]
))
story.append(spacer(0.4))

# ============================================================
# SECTION 9 - QUICK REFERENCE SUMMARY TABLE
# ============================================================
story.append(PageBreak())
story.append(section_banner("9. RAPID REVISION: KEY FACTS FOR EXAMINATIONS", DARK_BLUE))
story.append(spacer(0.2))

qr_data = [
    [Paragraph("Disorder", TABLE_HEADER),
     Paragraph("Pathognomonic / Buzzword", TABLE_HEADER),
     Paragraph("Lab Hallmark", TABLE_HEADER),
     Paragraph("Key Prevention", TABLE_HEADER)],
    ["Kwashiorkor", "Fatty liver + oedema + flaky paint skin", "Low albumin; lipid accumulation in liver", "Protein-rich weaning foods"],
    ["Marasmus", "'Old man face'; brain-sparing; no oedema", "Low all indices; preserved albumin", "Caloric supplementation (RUTF)"],
    ["Vitamin A", "Bitot's spots; keratomalacia; night blindness", "Low serum retinol", "Biannual high-dose supplementation"],
    ["Iodine", "Endemic goitre; cretinism", "Low UIC; raised TSH; low T4", "Universal salt iodisation"],
    ["Iron (IDA)", "Koilonychia; pica; Plummer-Vinson", "Low ferritin; low MCHC; high TIBC", "Iron fortification; deworming"],
    ["Vitamin D", "Rachitic rosary; Looser zones", "Low 25(OH)D; low PO4; high ALP; high PTH", "Sun exposure; D3 supplementation"],
    ["Scurvy", "Perifollicular haemorrhages; corkscrew hairs", "Low plasma ascorbate; prolonged PT", "Citrus fruits; 65-90 mg/day Vit C"],
    ["Pellagra", "3 Ds: Dermatitis, Diarrhoea, Dementia", "Low urinary N-methyl nicotinamide", "Niacin fortification; dietary diversification"],
    ["Folate/B12", "Megaloblastic anaemia; NTDs (folate)", "Raised MCV; hypersegmented neutrophils", "Periconceptional folate; B12 injections"],
    ["Thiamine", "Wernicke triad: ophthalmoplegia, ataxia, confusion", "Low RBC transketolase activity", "Thiamine supplementation in alcoholics"],
    ["Obesity", "Metabolic syndrome; NAFLD; increased cancer risk", "High BMI, HbA1c, LDL, ALT", "Diet + exercise; GLP-1 agonists; surgery"],
]

qr_t = [[Paragraph(c, TABLE_CELL if i > 0 else TABLE_HEADER) for c in row] for i, row in enumerate(qr_data)]
qr_t[0] = [Paragraph(c, TABLE_HEADER) for c in qr_data[0]]

qrt = Table(qr_t, colWidths=[3.8*cm, 5*cm, 4.2*cm, 4*cm])
qrt.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), DARK_BLUE),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [LIGHT_GREY, colors.white]),
    ("BOX",           (0,0), (-1,-1), 1, MID_BLUE),
    ("INNERGRID",     (0,0), (-1,-1), 0.4, colors.HexColor("#BDC3C7")),
    ("TOPPADDING",    (0,0), (-1,-1), 5), ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 5), ("VALIGN", (0,0), (-1,-1), "TOP"),
]))
story.append(qrt)
story.append(spacer(0.4))

# ============================================================
# SECTION 10 - GLOBAL PUBLIC HEALTH STRATEGIES
# ============================================================
story.append(section_banner("10. GLOBAL PUBLIC HEALTH STRATEGIES", GREEN))
story.append(spacer(0.2))

story.append(para(
    "The following nutrition interventions are recognised as among the most cost-effective public health "
    "measures available (Copenhagen Consensus, WHO, World Bank):"
))
story.append(spacer(0.1))

strategies = [
    ("Universal Salt Iodisation (USI)", "Eliminates IDD; target 15-40 ppm iodate; > 90% coverage in many countries."),
    ("Vitamin A Supplementation (VAS)", "WHO/UNICEF programme; biannual high-dose capsules for children 6-59 months; reduces under-5 mortality by 12-24%."),
    ("Iron and Folic Acid Supplementation", "Antenatal IFA supplements; weekly IFA for adolescent girls; dramatically reduces anaemia and NTD prevalence."),
    ("Food Fortification", "Staple food fortification (flour, rice, oil, sugar) with iron, vitamin A, D, folic acid, B12 - reaches entire population."),
    ("Exclusive Breastfeeding Promotion", "Protects against malnutrition and micronutrient deficiency in infants 0-6 months."),
    ("Deworming Programmes", "Mass drug administration in endemic areas - reduces iron loss and improves nutritional status."),
    ("Biofortification", "Developing micronutrient-enriched crop varieties (Orange Sweet Potato for Vit A; iron-biofortified beans/wheat)."),
    ("Community-Based Management", "IMAM protocol for severe acute malnutrition using RUTF; outpatient model has transformed outcomes."),
]

for title, desc in strategies:
    row_data = [[
        Paragraph(f"<b>{title}</b>", S("ST", fontSize=10, fontName="Helvetica-Bold", textColor=DARK_BLUE, leading=14)),
        Paragraph(desc, BODY),
    ]]
    rt = Table(row_data, colWidths=[5*cm, 12*cm])
    rt.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (0,0), LIGHT_GREEN),
        ("BACKGROUND",    (1,0), (1,0), colors.white),
        ("BOX",           (0,0), (-1,-1), 0.5, colors.HexColor("#A5D6A7")),
        ("TOPPADDING",    (0,0), (-1,-1), 6), ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("LEFTPADDING",   (0,0), (-1,-1), 8), ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    story.append(rt)
    story.append(Spacer(1, 2))

story.append(spacer(0.3))

# -------- FOOTER / REFERENCES --------
story.append(hr(DARK_BLUE, 1.5))
story.append(Paragraph(
    "<b>References & Sources:</b> Robbins & Kumar Basic Pathology (10th ed.) | Robbins, Cotran & Kumar Pathologic "
    "Basis of Disease (10th ed.) | Park's Textbook of Preventive and Social Medicine (25th ed.) | "
    "Lippincott Illustrated Reviews: Biochemistry (8th ed.) | Harrison's Principles of Internal Medicine (22nd ed.) | "
    "WHO Nutrition Guidelines (2024) | Goodman & Gilman's Pharmacological Basis of Therapeutics",
    S("Ref", fontSize=8, fontName="Helvetica-Oblique", textColor=MID_GREY, leading=11, spaceAfter=4)
))
story.append(Paragraph(
    "This document is prepared for medical student educational use. Always verify clinical decisions "
    "against current institutional guidelines and standard textbooks.",
    S("Disclaimer", fontSize=8, fontName="Helvetica-Oblique", textColor=colors.HexColor("#C0392B"),
      leading=11, spaceAfter=2)
))

# ============================================================
# Build
# ============================================================
def add_page_number(canvas, doc):
    canvas.saveState()
    canvas.setFont("Helvetica", 8)
    canvas.setFillColor(MID_GREY)
    page_num = canvas.getPageNumber()
    text = f"Nutritional Disorders Summary  |  Page {page_num}  |  For Medical Students"
    canvas.drawCentredString(A4[0] / 2.0, 1.2*cm, text)
    canvas.restoreState()

doc.build(story, onFirstPage=add_page_number, onLaterPages=add_page_number)
print(f"PDF created at: {OUTPUT}")
print(f"File size: {os.path.getsize(OUTPUT):,} bytes")

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