Viva Answers: Glands of Head and Neck

from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.units import mm, cm
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, PageBreak, KeepTogether
)
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.enums import TA_LEFT, TA_CENTER, TA_JUSTIFY
from reportlab.platypus.flowables import Flowable
from reportlab.graphics.shapes import Drawing, Rect, String, Line, Circle, Polygon
from reportlab.graphics import renderPDF
import math

# ─── COLOUR PALETTE ────────────────────────────────────────────────
NAVY       = colors.HexColor("#1a2e4a")
TEAL       = colors.HexColor("#1abc9c")
GOLD       = colors.HexColor("#f39c12")
LIGHT_BLUE = colors.HexColor("#d6eaf8")
LIGHT_TEAL = colors.HexColor("#d1f2eb")
LIGHT_GOLD = colors.HexColor("#fef9e7")
LIGHT_GREY = colors.HexColor("#f4f6f7")
MID_GREY   = colors.HexColor("#bdc3c7")
DARK_GREY  = colors.HexColor("#5d6d7e")
RED        = colors.HexColor("#e74c3c")
LIGHT_RED  = colors.HexColor("#fadbd8")
PURPLE     = colors.HexColor("#8e44ad")
LIGHT_PURPLE = colors.HexColor("#f5eef8")
GREEN      = colors.HexColor("#27ae60")
LIGHT_GREEN = colors.HexColor("#eafaf1")
ORANGE     = colors.HexColor("#e67e22")
LIGHT_ORANGE = colors.HexColor("#fdebd0")
WHITE      = colors.white
BLACK      = colors.black

PAGE_W, PAGE_H = A4
MARGIN = 18 * mm

# ─── STYLES ────────────────────────────────────────────────────────
styles = getSampleStyleSheet()

def S(name, **kw):
    base = styles.get(name, styles["Normal"])
    return ParagraphStyle(name + str(id(kw)), parent=base, **kw)

title_style = S("Normal",
    fontSize=28, textColor=WHITE, fontName="Helvetica-Bold",
    alignment=TA_CENTER, leading=34)

subtitle_style = S("Normal",
    fontSize=13, textColor=colors.HexColor("#aed6f1"),
    alignment=TA_CENTER, fontName="Helvetica", leading=18)

q_style = S("Normal",
    fontSize=13, textColor=WHITE, fontName="Helvetica-Bold",
    leading=17, leftIndent=4)

h1_style = S("Normal",
    fontSize=11, textColor=NAVY, fontName="Helvetica-Bold",
    leading=15, spaceBefore=4, spaceAfter=2)

body_style = S("Normal",
    fontSize=9.5, textColor=colors.HexColor("#2c3e50"),
    fontName="Helvetica", leading=14, spaceAfter=2,
    leftIndent=8, alignment=TA_JUSTIFY)

bullet_style = S("Normal",
    fontSize=9.5, textColor=colors.HexColor("#2c3e50"),
    fontName="Helvetica", leading=14, leftIndent=14,
    bulletIndent=6, spaceAfter=1)

key_style = S("Normal",
    fontSize=9, textColor=NAVY, fontName="Helvetica-Bold",
    leading=13, leftIndent=8, spaceAfter=1)

note_style = S("Normal",
    fontSize=8.5, textColor=DARK_GREY, fontName="Helvetica-Oblique",
    leading=12, leftIndent=8)

cell_style = S("Normal",
    fontSize=8.5, textColor=colors.HexColor("#2c3e50"),
    fontName="Helvetica", leading=12)

cell_bold = S("Normal",
    fontSize=8.5, textColor=NAVY, fontName="Helvetica-Bold",
    leading=12)

# ─── HELPER FLOWABLES ──────────────────────────────────────────────
def spacer(h=4):
    return Spacer(1, h * mm)

def hr(color=TEAL, thickness=0.5):
    return HRFlowable(width="100%", thickness=thickness, color=color, spaceAfter=2*mm, spaceBefore=1*mm)

def section_header(num, question, color=NAVY, bg=LIGHT_BLUE):
    """Returns a styled question-number + question block."""
    badge_text = f"Q{num}"
    data = [[
        Paragraph(f'<font color="white"><b>{badge_text}</b></font>',
                  S("Normal", fontSize=11, fontName="Helvetica-Bold",
                    alignment=TA_CENTER, leading=14)),
        Paragraph(question,
                  S("Normal", fontSize=10.5, fontName="Helvetica-Bold",
                    textColor=NAVY, leading=14))
    ]]
    t = Table(data, colWidths=[14*mm, PAGE_W - 2*MARGIN - 14*mm - 4*mm])
    t.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (0,0), TEAL),
        ("BACKGROUND", (1,0), (1,0), bg),
        ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
        ("LEFTPADDING", (0,0), (-1,-1), 5),
        ("RIGHTPADDING", (0,0), (-1,-1), 5),
        ("TOPPADDING", (0,0), (-1,-1), 6),
        ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("ROWBACKGROUNDS", (0,0), (-1,-1), [None]),
        ("ROUNDEDCORNERS", [3]),
    ]))
    return t

def bullet(text, indent=0):
    return Paragraph(f"• {text}", S("Normal",
        fontSize=9.5, textColor=colors.HexColor("#2c3e50"),
        fontName="Helvetica", leading=14,
        leftIndent=14+indent, bulletIndent=6+indent, spaceAfter=1))

def sub_bullet(text):
    return Paragraph(f"  – {text}", S("Normal",
        fontSize=9, textColor=DARK_GREY,
        fontName="Helvetica", leading=13,
        leftIndent=22, spaceAfter=1))

def key_point(label, text):
    return Paragraph(f'<font color="#1a2e4a"><b>{label}:</b></font> {text}', body_style)

def info_box(text, bg=LIGHT_TEAL, border=TEAL):
    data = [[Paragraph(text, S("Normal", fontSize=9, fontName="Helvetica",
                               textColor=colors.HexColor("#1a5276"),
                               leading=13, leftIndent=2))]]
    t = Table(data, colWidths=[PAGE_W - 2*MARGIN - 4*mm])
    t.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), bg),
        ("BOX", (0,0), (-1,-1), 1.2, border),
        ("LEFTPADDING", (0,0), (-1,-1), 8),
        ("RIGHTPADDING", (0,0), (-1,-1), 8),
        ("TOPPADDING", (0,0), (-1,-1), 6),
        ("BOTTOMPADDING", (0,0), (-1,-1), 6),
    ]))
    return t

def warning_box(text):
    return info_box(f"⚠ <b>Clinical Pearl:</b> {text}", bg=LIGHT_GOLD, border=GOLD)

def make_table(headers, rows, col_widths=None, header_bg=NAVY):
    data = [[Paragraph(h, S("Normal", fontSize=8.5, fontName="Helvetica-Bold",
                             textColor=WHITE, leading=11, alignment=TA_CENTER)) for h in headers]]
    for row in rows:
        data.append([Paragraph(str(c), S("Normal", fontSize=8, fontName="Helvetica",
                                          textColor=colors.HexColor("#2c3e50"),
                                          leading=11)) for c in row])
    w = col_widths or [(PAGE_W - 2*MARGIN - 4*mm) / len(headers)] * len(headers)
    t = Table(data, colWidths=w)
    style = [
        ("BACKGROUND", (0,0), (-1,0), header_bg),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [LIGHT_GREY, WHITE]),
        ("GRID", (0,0), (-1,-1), 0.4, MID_GREY),
        ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
        ("LEFTPADDING", (0,0), (-1,-1), 5),
        ("RIGHTPADDING", (0,0), (-1,-1), 5),
        ("TOPPADDING", (0,0), (-1,-1), 4),
        ("BOTTOMPADDING", (0,0), (-1,-1), 4),
        ("ALIGN", (0,0), (-1,-1), "LEFT"),
    ]
    t.setStyle(TableStyle(style))
    return t

# ─── DIAGRAM FLOWABLES ─────────────────────────────────────────────

class ParotidDiagram(Flowable):
    """Schematic of parotid gland showing contents from superficial to deep."""
    def __init__(self, w=170*mm, h=90*mm):
        super().__init__()
        self.width = w
        self.height = h

    def draw(self):
        from reportlab.graphics.shapes import Drawing, Rect, String, Line, Circle, Polygon, Path
        c = self.canv
        W, H = self.width, self.height

        # Background
        c.setFillColor(colors.HexColor("#eaf4fb"))
        c.roundRect(0, 0, W, H, 6, fill=1, stroke=0)

        # Title
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 10)
        c.drawCentredString(W/2, H-10*mm, "Structures Inside the Parotid Gland (Superficial → Deep)")

        # Gland outline (ellipse)
        cx, cy = W*0.38, H*0.45
        rx, ry = W*0.25, H*0.36
        c.setStrokeColor(colors.HexColor("#f39c12"))
        c.setFillColor(colors.HexColor("#fef5e7"))
        c.setLineWidth(2)
        c.ellipse(cx-rx, cy-ry, cx+rx, cy+ry, fill=1, stroke=1)

        c.setFillColor(colors.HexColor("#e67e22"))
        c.setFont("Helvetica-Bold", 9)
        c.drawCentredString(cx, cy + ry + 4*mm, "PAROTID GLAND")

        # Layers from superficial to deep (as horizontal bands inside ellipse)
        layers = [
            (0.85, colors.HexColor("#f9e79f"), "Parotid Lymph Nodes"),
            (0.62, colors.HexColor("#a9cce3"), "Facial Nerve [VII] & branches"),
            (0.42, colors.HexColor("#f1948a"), "Retromandibular Vein"),
            (0.22, colors.HexColor("#a9dfbf"), "External Carotid Artery"),
        ]
        for frac, col, label in layers:
            y_pos = cy - ry + frac * 2 * ry
            half_w = rx * math.sqrt(max(0, 1 - ((y_pos - cy)/ry)**2)) * 0.9
            c.setFillColor(col)
            c.setStrokeColor(WHITE)
            c.setLineWidth(0.5)
            c.rect(cx - half_w, y_pos - 5, half_w*2, 10, fill=1, stroke=1)
            c.setFillColor(NAVY)
            c.setFont("Helvetica", 7.5)
            c.drawCentredString(cx, y_pos - 2.5, label)

        # Legend / arrows on right side
        legend_x = W * 0.70
        legend_y = H * 0.82
        entries = [
            (colors.HexColor("#f9e79f"), "Lymph Nodes (superficial)"),
            (colors.HexColor("#a9cce3"), "Facial N. [VII]"),
            (colors.HexColor("#f1948a"), "Retromandibular Vein"),
            (colors.HexColor("#a9dfbf"), "Ext. Carotid Artery (deep)"),
        ]
        c.setFont("Helvetica-Bold", 8)
        c.setFillColor(NAVY)
        c.drawString(legend_x, legend_y + 4*mm, "Contents (S→D):")
        for i, (col, lbl) in enumerate(entries):
            y = legend_y - i * 9*mm
            c.setFillColor(col)
            c.rect(legend_x, y - 3, 8, 8, fill=1, stroke=0)
            c.setFillColor(DARK_GREY)
            c.setFont("Helvetica", 7.5)
            c.drawString(legend_x + 10*mm, y - 2, lbl)

        # Mnemonic
        c.setFillColor(LIGHT_TEAL)
        c.roundRect(W*0.02, 2*mm, W*0.44, 10*mm, 4, fill=1, stroke=0)
        c.setFillColor(TEAL)
        c.setFont("Helvetica-Bold", 8)
        c.drawString(W*0.04, 5*mm, "Mnemonic: Some Teenagers Are Really Playful")
        c.setFont("Helvetica", 7)
        c.setFillColor(DARK_GREY)
        c.drawString(W*0.04, 2.5*mm, "Skin · Trunk(Facial N) · Artery(Ext Carotid) · Retromandibular V · Parotid nodes")


class ThyroidDiagram(Flowable):
    """Schematic of thyroid gland anatomy."""
    def __init__(self, w=170*mm, h=100*mm):
        super().__init__()
        self.width = w
        self.height = h

    def draw(self):
        c = self.canv
        W, H = self.width, self.height

        c.setFillColor(colors.HexColor("#e8f8f5"))
        c.roundRect(0, 0, W, H, 6, fill=1, stroke=0)

        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 10)
        c.drawCentredString(W/2, H - 9*mm, "Thyroid Gland – Anatomy & Blood Supply")

        # Trachea (central cylinder)
        tc_x, tc_y = W*0.42, H*0.22
        tc_w, tc_h = 24*mm, 40*mm
        c.setFillColor(colors.HexColor("#d5d8dc"))
        c.setStrokeColor(MID_GREY)
        c.setLineWidth(1)
        c.roundRect(tc_x, tc_y, tc_w, tc_h, 4, fill=1, stroke=1)
        c.setFillColor(DARK_GREY)
        c.setFont("Helvetica", 7)
        for i in range(4):
            yy = tc_y + 8*mm + i*8*mm
            if yy < tc_y + tc_h - 4*mm:
                c.setStrokeColor(MID_GREY)
                c.setLineWidth(0.7)
                c.line(tc_x + 2*mm, yy, tc_x + tc_w - 2*mm, yy)
        c.setFillColor(DARK_GREY)
        c.setFont("Helvetica", 7.5)
        c.drawCentredString(tc_x + tc_w/2, tc_y - 5*mm, "Trachea")

        # Thyroid lobes
        lobe_h = 32*mm
        lobe_w = 20*mm
        # Right lobe
        rl_x = tc_x - lobe_w - 1*mm
        rl_y = tc_y + 4*mm
        c.setFillColor(colors.HexColor("#a9dfbf"))
        c.setStrokeColor(GREEN)
        c.setLineWidth(1.5)
        c.roundRect(rl_x, rl_y, lobe_w, lobe_h, 6, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 7.5)
        c.drawCentredString(rl_x + lobe_w/2, rl_y + lobe_h/2 - 3, "Right")
        c.drawCentredString(rl_x + lobe_w/2, rl_y + lobe_h/2 - 11, "Lobe")

        # Left lobe
        ll_x = tc_x + tc_w + 1*mm
        ll_y = tc_y + 4*mm
        c.setFillColor(colors.HexColor("#a9dfbf"))
        c.setStrokeColor(GREEN)
        c.setLineWidth(1.5)
        c.roundRect(ll_x, ll_y, lobe_w, lobe_h, 6, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 7.5)
        c.drawCentredString(ll_x + lobe_w/2, ll_y + lobe_h/2 - 3, "Left")
        c.drawCentredString(ll_x + lobe_w/2, ll_y + lobe_h/2 - 11, "Lobe")

        # Isthmus
        ist_y = tc_y + 12*mm
        ist_h = 8*mm
        c.setFillColor(colors.HexColor("#7dcea0"))
        c.setStrokeColor(GREEN)
        c.setLineWidth(1)
        c.rect(tc_x, ist_y, tc_w, ist_h, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 7)
        c.drawCentredString(tc_x + tc_w/2, ist_y + 2.5*mm, "Isthmus")

        # Pyramidal lobe
        pyr_x = tc_x + tc_w/2 - 4*mm
        pyr_y = ist_y + ist_h
        c.setFillColor(colors.HexColor("#58d68d"))
        c.setStrokeColor(GREEN)
        path = c.beginPath()
        path.moveTo(pyr_x, pyr_y)
        path.lineTo(pyr_x + 8*mm, pyr_y)
        path.lineTo(pyr_x + 4*mm, pyr_y + 14*mm)
        path.close()
        c.drawPath(path, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica", 6.5)
        c.drawCentredString(pyr_x + 4*mm, pyr_y + 15*mm, "Pyramidal lobe")

        # Superior thyroid arteries
        c.setStrokeColor(RED)
        c.setLineWidth(1.5)
        # Right STA
        c.line(rl_x + lobe_w/2, rl_y + lobe_h, rl_x + lobe_w/2, rl_y + lobe_h + 12*mm)
        c.setFillColor(RED)
        c.setFont("Helvetica", 7)
        c.drawCentredString(rl_x + lobe_w/2, rl_y + lobe_h + 13*mm, "Sup. Thyroid A.")
        # Left STA
        c.setStrokeColor(RED)
        c.line(ll_x + lobe_w/2, ll_y + lobe_h, ll_x + lobe_w/2, ll_y + lobe_h + 12*mm)
        c.drawCentredString(ll_x + lobe_w/2, ll_y + lobe_h + 13*mm, "Sup. Thyroid A.")

        # Inferior thyroid arteries
        c.setStrokeColor(colors.HexColor("#c0392b"))
        c.setLineWidth(1.2)
        c.line(rl_x + lobe_w/2, rl_y, rl_x + lobe_w/2, rl_y - 8*mm)
        c.setFillColor(colors.HexColor("#c0392b"))
        c.setFont("Helvetica", 7)
        c.drawCentredString(rl_x + lobe_w/2, rl_y - 10*mm, "Inf. Thyroid A.")
        c.setStrokeColor(colors.HexColor("#c0392b"))
        c.line(ll_x + lobe_w/2, ll_y, ll_x + lobe_w/2, ll_y - 8*mm)
        c.drawCentredString(ll_x + lobe_w/2, ll_y - 10*mm, "Inf. Thyroid A.")

        # RLN labels
        c.setFillColor(PURPLE)
        c.setFont("Helvetica-BoldOblique", 7)
        c.drawString(rl_x - 18*mm, rl_y + 10*mm, "RLN →")
        c.drawString(ll_x + lobe_w + 2*mm, ll_y + 10*mm, "← RLN")

        # Parathyroid dots
        for (px, py) in [(rl_x + 2, rl_y + 22*mm), (rl_x + 2, rl_y + 10*mm),
                         (ll_x + lobe_w - 6, ll_y + 22*mm), (ll_x + lobe_w - 6, ll_y + 10*mm)]:
            c.setFillColor(colors.HexColor("#f39c12"))
            c.circle(px + 2, py, 3*mm, fill=1, stroke=0)
        c.setFillColor(GOLD)
        c.setFont("Helvetica-Bold", 7)
        c.drawString(W*0.01, H*0.38, "● Parathyroid")
        c.drawString(W*0.01, H*0.33, "    glands (×4)")

        # Pretracheal fascia label
        c.setFillColor(colors.HexColor("#7fb3d3"))
        c.setFont("Helvetica-Oblique", 7)
        c.drawString(W*0.68, H*0.42, "Pretracheal fascia")
        c.drawString(W*0.68, H*0.37, "→ moves with")
        c.drawString(W*0.68, H*0.32, "   deglutition")


class SalivaryHistoDiagram(Flowable):
    """Comparison diagram of histology of 3 major salivary glands."""
    def __init__(self, w=170*mm, h=70*mm):
        super().__init__()
        self.width = w
        self.height = h

    def draw(self):
        c = self.canv
        W, H = self.width, self.height
        c.setFillColor(colors.HexColor("#f8f9fa"))
        c.roundRect(0, 0, W, H, 5, fill=1, stroke=0)

        c.setFont("Helvetica-Bold", 9.5)
        c.setFillColor(NAVY)
        c.drawCentredString(W/2, H - 8*mm, "Histological Comparison of Major Salivary Glands")

        panels = [
            ("Parotid", colors.HexColor("#d6eaf8"), colors.HexColor("#2980b9"),
             "Purely SEROUS", ["Serous acini only", "Long intercalated ducts",
                               "Prominent striated ducts", "↑ Fat with age"]),
            ("Submandibular", colors.HexColor("#d5f5e3"), colors.HexColor("#1e8449"),
             "Mixed (Pred. SEROUS)", ["Serous + mucous acini", "Serous demilunes", 
                                       "Shorter intercalated ducts", "Well-developed ducts"]),
            ("Sublingual", colors.HexColor("#fdebd0"), colors.HexColor("#d35400"),
             "Mixed (Pred. MUCOUS)", ["Mucous acini dominant", "Few serous demilunes",
                                       "Absent intercalated ducts", "Short striated ducts"]),
        ]
        pw = (W - 6*mm) / 3
        for i, (name, bg, hdr_col, type_text, bullets) in enumerate(panels):
            px = 2*mm + i * pw
            py = 2*mm
            ph = H - 12*mm
            c.setFillColor(bg)
            c.roundRect(px, py, pw - 1*mm, ph, 5, fill=1, stroke=0)
            c.setFillColor(hdr_col)
            c.roundRect(px, py + ph - 14*mm, pw - 1*mm, 14*mm, 5, fill=1, stroke=0)
            c.setFillColor(WHITE)
            c.setFont("Helvetica-Bold", 9)
            c.drawCentredString(px + (pw - 1*mm)/2, py + ph - 8*mm, name)
            c.setFont("Helvetica-BoldOblique", 7)
            c.drawCentredString(px + (pw - 1*mm)/2, py + ph - 13*mm, type_text)
            c.setFillColor(NAVY)
            c.setFont("Helvetica", 7.5)
            for j, bl in enumerate(bullets):
                yy = py + ph - 18*mm - j*7.5*mm
                c.drawString(px + 3*mm, yy, f"• {bl}")

            # Simple acinar diagram
            acini_x = px + (pw-1*mm)/2
            acini_y = py + 12*mm
            if i == 0:  # parotid - all serous (blue dots)
                for dx, dy in [(-6,4), (0,8), (6,4), (-3,-2), (3,-2)]:
                    c.setFillColor(colors.HexColor("#5dade2"))
                    c.circle(acini_x + dx*mm, acini_y + dy*mm, 2.5*mm, fill=1, stroke=0)
            elif i == 1:  # submandibular - mixed
                for dx, dy in [(-6,4), (6,4), (-3,-2)]:
                    c.setFillColor(colors.HexColor("#5dade2"))
                    c.circle(acini_x + dx*mm, acini_y + dy*mm, 2.5*mm, fill=1, stroke=0)
                for dx, dy in [(0,8), (3,-2)]:
                    c.setFillColor(colors.HexColor("#f0b27a"))
                    c.circle(acini_x + dx*mm, acini_y + dy*mm, 2.5*mm, fill=1, stroke=0)
            else:  # sublingual - mostly mucous
                for dx, dy in [(-6,4), (0,8), (6,4), (3,-2)]:
                    c.setFillColor(colors.HexColor("#f0b27a"))
                    c.circle(acini_x + dx*mm, acini_y + dy*mm, 2.5*mm, fill=1, stroke=0)
                for dx, dy in [(-3,-2)]:
                    c.setFillColor(colors.HexColor("#5dade2"))
                    c.circle(acini_x + dx*mm, acini_y + dy*mm, 2.5*mm, fill=1, stroke=0)

        # Legend
        legend_y = 0.5*mm
        c.setFillColor(colors.HexColor("#5dade2"))
        c.rect(W*0.3, legend_y, 6, 6, fill=1, stroke=0)
        c.setFillColor(DARK_GREY)
        c.setFont("Helvetica", 7)
        c.drawString(W*0.3 + 8, legend_y + 1, "Serous acini")
        c.setFillColor(colors.HexColor("#f0b27a"))
        c.rect(W*0.5, legend_y, 6, 6, fill=1, stroke=0)
        c.drawString(W*0.5 + 8, legend_y + 1, "Mucous acini")


class ThyroglosalDiagram(Flowable):
    """Thyroglossal cyst development diagram."""
    def __init__(self, w=170*mm, h=80*mm):
        super().__init__()
        self.width = w
        self.height = h

    def draw(self):
        c = self.canv
        W, H = self.width, self.height
        c.setFillColor(colors.HexColor("#fdfefe"))
        c.roundRect(0, 0, W, H, 5, fill=1, stroke=0)

        c.setFont("Helvetica-Bold", 10)
        c.setFillColor(NAVY)
        c.drawCentredString(W/2, H - 8*mm, "Thyroid Development & Thyroglossal Cyst")

        # Midline sagittal view
        mid_x = W * 0.45
        # Foramen cecum (tongue base)
        c.setFillColor(colors.HexColor("#fdebd0"))
        c.roundRect(mid_x - 18*mm, H*0.75, 36*mm, 12*mm, 5, fill=1, stroke=0)
        c.setStrokeColor(ORANGE)
        c.roundRect(mid_x - 18*mm, H*0.75, 36*mm, 12*mm, 5, fill=0, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 8)
        c.drawCentredString(mid_x, H*0.75 + 6*mm, "Tongue Base")
        c.setFillColor(ORANGE)
        c.setFont("Helvetica", 7)
        c.drawCentredString(mid_x, H*0.75 + 2*mm, "Foramen Cecum (origin)")

        # Descent path
        c.setStrokeColor(colors.HexColor("#85c1e9"))
        c.setLineWidth(2)
        c.setDash([3,3])
        c.line(mid_x, H*0.75, mid_x, H*0.20)
        c.setDash([])

        # Hyoid bone
        hyoid_y = H * 0.58
        c.setFillColor(colors.HexColor("#d5d8dc"))
        c.setStrokeColor(MID_GREY)
        c.setLineWidth(1)
        c.roundRect(mid_x - 14*mm, hyoid_y - 3*mm, 28*mm, 6*mm, 3, fill=1, stroke=1)
        c.setFillColor(DARK_GREY)
        c.setFont("Helvetica-Bold", 7)
        c.drawCentredString(mid_x, hyoid_y - 0.5*mm, "Hyoid Bone")

        # Thyroid cartilage
        thyc_y = H * 0.42
        c.setFillColor(colors.HexColor("#eaf2ff"))
        c.setStrokeColor(colors.HexColor("#5dade2"))
        c.roundRect(mid_x - 16*mm, thyc_y - 3*mm, 32*mm, 6*mm, 3, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 7)
        c.drawCentredString(mid_x, thyc_y - 0.5*mm, "Thyroid Cartilage")

        # Final thyroid position
        c.setFillColor(colors.HexColor("#a9dfbf"))
        c.setStrokeColor(GREEN)
        c.setLineWidth(1.5)
        c.roundRect(mid_x - 18*mm, H*0.12, 36*mm, 14*mm, 5, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 8)
        c.drawCentredString(mid_x, H*0.12 + 7.5*mm, "Final Position of Thyroid")
        c.setFont("Helvetica", 7)
        c.drawCentredString(mid_x, H*0.12 + 3*mm, "Anterior to trachea, below cricoid")

        # Cyst possibilities
        positions = [
            (H*0.70, colors.HexColor("#f9ebea"), RED, "Lingual thyroid"),
            (H*0.60, colors.HexColor("#f9ebea"), RED, "Sublingual cyst"),
            (H*0.50, colors.HexColor("#f9ebea"), RED, "Suprahyoid cyst"),
            (H*0.42, colors.HexColor("#f9ebea"), RED, "At hyoid"),
            (H*0.30, colors.HexColor("#f9ebea"), RED, "Infrahyoid (most common 65%)"),
        ]
        for yy, bg, bc, lbl in positions:
            cx2 = mid_x + 28*mm
            c.setFillColor(bg)
            c.setStrokeColor(bc)
            c.setLineWidth(0.7)
            c.roundRect(cx2, yy - 3*mm, 38*mm, 7*mm, 3, fill=1, stroke=1)
            c.setFillColor(RED)
            c.setFont("Helvetica", 7)
            c.drawString(cx2 + 2*mm, yy - 0.5*mm, lbl)
            c.setStrokeColor(RED)
            c.setLineWidth(0.5)
            c.setDash([2,2])
            c.line(mid_x, yy + 0.5*mm, cx2, yy + 0.5*mm)
            c.setDash([])

        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 8)
        c.drawString(mid_x + 28*mm, H*0.76, "Sites of Ectopic/Cysts:")

        # Sistrunk note
        c.setFillColor(LIGHT_TEAL)
        c.roundRect(1*mm, 0.5*mm, 38*mm, 10*mm, 3, fill=1, stroke=0)
        c.setFillColor(TEAL)
        c.setFont("Helvetica-Bold", 7)
        c.drawString(3*mm, 7*mm, "Sistrunk Operation:")
        c.setFillColor(DARK_GREY)
        c.setFont("Helvetica", 6.5)
        c.drawString(3*mm, 3.5*mm, "Cyst + central hyoid + tract to foramen cecum")


class PituitaryDiagram(Flowable):
    """Pituitary gland – divisions and tracts diagram."""
    def __init__(self, w=170*mm, h=85*mm):
        super().__init__()
        self.width = w
        self.height = h

    def draw(self):
        c = self.canv
        W, H = self.width, self.height
        c.setFillColor(colors.HexColor("#f5eef8"))
        c.roundRect(0, 0, W, H, 5, fill=1, stroke=0)

        c.setFont("Helvetica-Bold", 10)
        c.setFillColor(NAVY)
        c.drawCentredString(W/2, H - 8*mm, "Pituitary Gland – Divisions, Tracts & Portal System")

        # Hypothalamus box
        c.setFillColor(colors.HexColor("#d2b4de"))
        c.setStrokeColor(PURPLE)
        c.setLineWidth(1.5)
        c.roundRect(W*0.28, H*0.72, W*0.44, 14*mm, 5, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 9)
        c.drawCentredString(W/2, H*0.72 + 9*mm, "HYPOTHALAMUS")
        c.setFont("Helvetica", 7.5)
        c.drawCentredString(W/2, H*0.72 + 4*mm, "Supraoptic & Paraventricular nuclei")

        # Stalk
        stalk_x = W/2 - 5*mm
        stalk_y_top = H*0.72
        stalk_y_bot = H*0.46
        c.setFillColor(colors.HexColor("#d7bde2"))
        c.rect(stalk_x, stalk_y_bot, 10*mm, stalk_y_top - stalk_y_bot, fill=1, stroke=0)
        c.setFillColor(PURPLE)
        c.setFont("Helvetica-Oblique", 7)
        c.drawCentredString(W/2 + 14*mm, (stalk_y_top + stalk_y_bot)/2, "Infundibular stalk")

        # Anterior pituitary
        c.setFillColor(colors.HexColor("#aed6f1"))
        c.setStrokeColor(colors.HexColor("#2980b9"))
        c.setLineWidth(1.5)
        c.roundRect(W*0.08, H*0.15, W*0.37, H*0.30, 6, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 8.5)
        c.drawCentredString(W*0.08 + W*0.37/2, H*0.15 + H*0.30*0.72, "ANTERIOR PITUITARY")
        c.setFont("Helvetica-Bold", 7.5)
        c.setFillColor(colors.HexColor("#1a5276"))
        c.drawCentredString(W*0.08 + W*0.37/2, H*0.15 + H*0.30*0.52, "Adenohypophysis")
        hormones_ant = ["TSH  LH  FSH", "GH  ACTH  Prolactin"]
        c.setFont("Helvetica", 7)
        c.setFillColor(DARK_GREY)
        for j, h_text in enumerate(hormones_ant):
            c.drawCentredString(W*0.08 + W*0.37/2, H*0.15 + H*0.30*0.30 - j*8*mm, h_text)

        # Posterior pituitary
        c.setFillColor(colors.HexColor("#a9dfbf"))
        c.setStrokeColor(GREEN)
        c.setLineWidth(1.5)
        c.roundRect(W*0.55, H*0.15, W*0.37, H*0.30, 6, fill=1, stroke=1)
        c.setFillColor(NAVY)
        c.setFont("Helvetica-Bold", 8.5)
        c.drawCentredString(W*0.55 + W*0.37/2, H*0.15 + H*0.30*0.72, "POSTERIOR PITUITARY")
        c.setFont("Helvetica-Bold", 7.5)
        c.setFillColor(colors.HexColor("#1e8449"))
        c.drawCentredString(W*0.55 + W*0.37/2, H*0.15 + H*0.30*0.52, "Neurohypophysis")
        c.setFont("Helvetica", 7)
        c.setFillColor(DARK_GREY)
        c.drawCentredString(W*0.55 + W*0.37/2, H*0.15 + H*0.30*0.30, "ADH  +  Oxytocin")
        c.setFont("Helvetica-BoldOblique", 6.5)
        c.setFillColor(RED)
        c.drawCentredString(W*0.55 + W*0.37/2, H*0.15 + H*0.30*0.12, "No BBB (CVO)")

        # Portal system arrows (left)
        c.setStrokeColor(colors.HexColor("#2980b9"))
        c.setLineWidth(1.5)
        portal_x = W*0.08 + W*0.37/2
        c.line(portal_x, stalk_y_bot, portal_x, H*0.15 + H*0.30)
        # Arrow head
        c.setFillColor(colors.HexColor("#2980b9"))
        path = c.beginPath()
        path.moveTo(portal_x - 3*mm, H*0.15 + H*0.30 + 0.5*mm)
        path.lineTo(portal_x + 3*mm, H*0.15 + H*0.30 + 0.5*mm)
        path.lineTo(portal_x, H*0.15 + H*0.30 - 3*mm)
        path.close()
        c.drawPath(path, fill=1, stroke=0)
        c.setFillColor(colors.HexColor("#2980b9"))
        c.setFont("Helvetica-Bold", 7)
        c.drawString(W*0.03, (stalk_y_bot + H*0.15 + H*0.30)/2, "Portal")
        c.drawString(W*0.03, (stalk_y_bot + H*0.15 + H*0.30)/2 - 7, "system")

        # Tract arrows (right)
        c.setStrokeColor(GREEN)
        c.setLineWidth(1.5)
        tract_x = W*0.55 + W*0.37/2
        c.line(tract_x, stalk_y_bot, tract_x, H*0.15 + H*0.30)
        c.setFillColor(GREEN)
        path2 = c.beginPath()
        path2.moveTo(tract_x - 3*mm, H*0.15 + H*0.30 + 0.5*mm)
        path2.lineTo(tract_x + 3*mm, H*0.15 + H*0.30 + 0.5*mm)
        path2.lineTo(tract_x, H*0.15 + H*0.30 - 3*mm)
        path2.close()
        c.drawPath(path2, fill=1, stroke=0)
        c.setFillColor(GREEN)
        c.setFont("Helvetica-Bold", 7)
        c.drawString(W*0.93, (stalk_y_bot + H*0.15 + H*0.30)/2, "Tract")
        c.drawString(W*0.88, (stalk_y_bot + H*0.15 + H*0.30)/2 - 7, "(axons)")

        # Labels at bottom
        c.setFillColor(colors.HexColor("#2980b9"))
        c.setFont("Helvetica", 6.5)
        c.drawCentredString(W*0.08 + W*0.37/2, H*0.06, "Releasing hormones via portal → ant. pituitary")
        c.setFillColor(GREEN)
        c.drawCentredString(W*0.55 + W*0.37/2, H*0.06, "ADH/OT transported via axons → released")


# ─── COVER PAGE ────────────────────────────────────────────────────
def make_cover():
    elements = []
    # Big colour banner
    data = [[Paragraph("GLANDS OF HEAD &amp; NECK", title_style)]]
    t = Table(data, colWidths=[PAGE_W - 2*MARGIN])
    t.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), NAVY),
        ("TOPPADDING", (0,0), (-1,-1), 18),
        ("BOTTOMPADDING", (0,0), (-1,-1), 8),
        ("LEFTPADDING", (0,0), (-1,-1), 10),
        ("RIGHTPADDING", (0,0), (-1,-1), 10),
        ("ROUNDEDCORNERS", [6]),
    ]))
    elements.append(t)
    elements.append(spacer(3))

    data2 = [[Paragraph("Complete Viva Answers with Visualisations", subtitle_style)]]
    t2 = Table(data2, colWidths=[PAGE_W - 2*MARGIN])
    t2.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), colors.HexColor("#2471a3")),
        ("TOPPADDING", (0,0), (-1,-1), 6),
        ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("ROUNDEDCORNERS", [4]),
    ]))
    elements.append(t2)
    elements.append(spacer(5))

    # Index table
    index_data = [
        [Paragraph("<b>Q#</b>", cell_bold), Paragraph("<b>Topic</b>", cell_bold), Paragraph("<b>Key Concept</b>", cell_bold)],
        ["Q1-3", "Gland Names & Salivary Glands", "Major + Minor salivary glands"],
        ["Q4", "Endocrine Glands in Neck", "Thyroid, Parathyroid, Pituitary, Pineal"],
        ["Q5", "Parotid Contents", "Facial N, Ext Carotid A, Retromandibular V"],
        ["Q6", "Parotid Duct", "Opens near upper 2nd molar"],
        ["Q7", "Parotid Capsule", "True (own) + False (investing fascia)"],
        ["Q8", "Parotid Swelling Pain & Orchitis", "Tight capsule; hematogenous mumps virus"],
        ["Q9", "Salivary Gland Histology", "Serous vs mucous; duct systems"],
        ["Q10-11", "Thyroid Location & Blood Supply", "Parts, arteries, veins, lymphatics"],
        ["Q12", "Thyroid Arteries (surgical imp.)", "Ext laryngeal N; RLN; parathyroid supply"],
        ["Q13", "Thyroid Moves with Deglutition", "Pretracheal fascia → bound to larynx/trachea"],
        ["Q14-16", "Thyroid Development & Anomalies", "Thyroglossal duct, ectopic thyroid, cysts"],
        ["Q17-18", "Para/Pituitary Location", "Parathyroid on thyroid; Pituitary in sella"],
        ["Q19-21", "Pituitary Tracts & BBB", "Hypothalamo-hypophyseal tract/portal; CVO"],
    ]
    iw = [15*mm, 60*mm, 80*mm]
    it = Table(index_data, colWidths=iw)
    it.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), NAVY),
        ("TEXTCOLOR", (0,0), (-1,0), WHITE),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [LIGHT_BLUE, WHITE]),
        ("GRID", (0,0), (-1,-1), 0.4, MID_GREY),
        ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
        ("LEFTPADDING", (0,0), (-1,-1), 6),
        ("TOPPADDING", (0,0), (-1,-1), 4),
        ("BOTTOMPADDING", (0,0), (-1,-1), 4),
        ("FONTNAME", (0,0), (-1,-1), "Helvetica"),
        ("FONTSIZE", (0,0), (-1,-1), 9),
        ("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTSIZE", (0,0), (-1,0), 9),
        ("TEXTCOLOR", (0,1), (-1,-1), NAVY),
    ]))
    elements.append(it)
    elements.append(spacer(4))
    elements.append(info_box(
        "📚 References: Gray's Anatomy for Students | BD Chaurasia | Dutta | Langman's Embryology | Snell's Neuroanatomy | Vishram Singh | Junqueira's Histology",
        bg=LIGHT_GOLD, border=GOLD
    ))
    elements.append(PageBreak())
    return elements


# ─── BUILD PDF ────────────────────────────────────────────────────
def build_pdf(path):
    doc = SimpleDocTemplate(
        path, pagesize=A4,
        leftMargin=MARGIN, rightMargin=MARGIN,
        topMargin=16*mm, bottomMargin=16*mm,
        title="Glands of Head and Neck – Viva Answers",
        author="Orris Medical"
    )

    def on_page(canvas, doc):
        canvas.saveState()
        # Header bar
        canvas.setFillColor(NAVY)
        canvas.rect(0, PAGE_H - 10*mm, PAGE_W, 10*mm, fill=1, stroke=0)
        canvas.setFillColor(WHITE)
        canvas.setFont("Helvetica-Bold", 8)
        canvas.drawString(MARGIN, PAGE_H - 7*mm, "Glands of Head & Neck – Viva Answers")
        canvas.setFont("Helvetica", 8)
        canvas.drawRightString(PAGE_W - MARGIN, PAGE_H - 7*mm, f"Page {doc.page}")
        # Footer bar
        canvas.setFillColor(TEAL)
        canvas.rect(0, 0, PAGE_W, 7*mm, fill=1, stroke=0)
        canvas.setFillColor(WHITE)
        canvas.setFont("Helvetica", 7)
        canvas.drawCentredString(PAGE_W/2, 2.5*mm, "Orris Medical | ITEM Book 2nd Edition Viva Series")
        canvas.restoreState()

    story = []
    story += make_cover()

    # ── Q1: Gland Names ──────────────────────────────────────────
    story.append(section_header(1, "Tell me the names of the glands of head and neck region"))
    story.append(spacer(2))

    gland_data = [
        [Paragraph("<b>Gland</b>", cell_bold), Paragraph("<b>Type</b>", cell_bold), Paragraph("<b>Location</b>", cell_bold)],
        ["Pituitary", "Endocrine", "Sella turcica, sphenoid bone"],
        ["Thyroid", "Endocrine", "Anterior neck below thyroid cartilage"],
        ["Parathyroid (×4)", "Endocrine", "Posterior surface of thyroid lobes"],
        ["Pineal", "Endocrine", "Epithalamus, between superior colliculi"],
        ["Parotid", "Exocrine (salivary)", "Preauricular, below EAM"],
        ["Submandibular", "Exocrine (salivary)", "Submandibular triangle, below mylohyoid"],
        ["Sublingual", "Exocrine (salivary)", "Floor of mouth, above mylohyoid"],
        ["Minor salivary glands", "Exocrine", "Mucosa of lips, cheeks, palate, tongue"],
    ]
    story.append(make_table([], gland_data, col_widths=[45*mm, 45*mm, 65*mm]))
    story.append(spacer(3))

    # ── Q2 & Q3: Salivary Glands ─────────────────────────────────
    story.append(section_header(2, "What are the major salivary glands? [Gray's 40th/520,522]"))
    story.append(spacer(2))
    story.append(key_point("Definition", "Three PAIRED glands that drain into the oral cavity via named ducts"))
    story.append(spacer(2))

    major_data = [
        [Paragraph("<b>Gland</b>", cell_bold), Paragraph("<b>Size</b>", cell_bold),
         Paragraph("<b>Type</b>", cell_bold), Paragraph("<b>Duct</b>", cell_bold), Paragraph("<b>Opens</b>", cell_bold)],
        ["Parotid", "Largest", "Purely SEROUS", "Stensen's duct (~5 cm)", "Opposite upper 2nd molar"],
        ["Submandibular", "Intermediate", "Mixed (pred. serous 70%)", "Wharton's duct", "Sublingual caruncle beside frenulum"],
        ["Sublingual", "Smallest", "Mixed (pred. mucous 70%)", "Ducts of Rivinus (×8-20)", "Sublingual fold"],
    ]
    story.append(make_table([], major_data, col_widths=[28*mm, 20*mm, 34*mm, 34*mm, 39*mm]))
    story.append(spacer(3))

    story.append(section_header(3, "Tell me some names of minor salivary glands. [Gray's 40th/520,522]"))
    story.append(spacer(2))
    minor_items = [
        "Labial glands (lips) – most numerous",
        "Buccal glands (cheeks)",
        "Palatine glands (hard & soft palate)",
        "Anterior lingual glands of Blandin-Nuhn (tip of tongue)",
        "Posterior lingual mucous glands",
        "Serous glands of von Ebner (around circumvallate papillae – clean taste buds)",
        "Molar glands (retromolar region)",
        "Glossopalatine glands",
    ]
    for item in minor_items:
        story.append(bullet(item))
    story.append(spacer(2))
    story.append(warning_box("Von Ebner's glands are the only PURELY SEROUS minor glands – they secrete lingual lipase and clean circumvallate papillae for repeated taste testing."))
    story.append(spacer(3))

    # ── Q4 ───────────────────────────────────────────────────────
    story.append(section_header(4, "What are the endocrine glands located in our neck?"))
    story.append(spacer(2))
    endo_items = [
        "<b>Pituitary gland</b> – hypophysis; in sella turcica of sphenoid (technically base of brain/skull)",
        "<b>Thyroid gland</b> – anterior neck, below thyroid cartilage",
        "<b>Parathyroid glands (×4)</b> – posterior surface of thyroid lobes",
        "<b>Endocrine part of hypothalamus</b> – releases TRH, GnRH, GHRH, CRH, dopamine",
        "<b>Pineal gland</b> – melatonin secretion; between superior colliculi",
    ]
    for item in endo_items:
        story.append(bullet(item))
    story.append(spacer(4))

    # ── Q5 + Parotid Diagram ─────────────────────────────────────
    story.append(section_header(5, "What are the structures present within the parotid gland? [BD 8th/117]"))
    story.append(spacer(2))
    story.append(info_box("<b>Mnemonic: \"Some Teenagers Are Really Playful\"</b><br/>"
                          "Skin → Facial N. (Trunk) → Arteries (Ext Carotid) → Retromandibular V → Parotid nodes"))
    story.append(spacer(2))

    parotid_data = [
        [Paragraph("<b>Structure</b>", cell_bold), Paragraph("<b>Details</b>", cell_bold)],
        ["Facial Nerve [VII]", "Enters via stylomastoid foramen → divides into upper & lower trunks → 5 terminal branches (Temporal, Zygomatic, Buccal, Marginal mandibular, Cervical)"],
        ["External Carotid Artery", "Enters inferior border → gives posterior auricular A → divides into Maxillary A + Superficial temporal A"],
        ["Retromandibular Vein", "Formed by superficial temporal V + maxillary V within gland; divides into anterior (→ facial V) and posterior (→ EJV) divisions"],
        ["Parotid Lymph Nodes", "Preauricular (superficial) and deep nodes; drain scalp, face, auricle, parotid; efferents → upper deep cervical nodes"],
        ["Auriculotemporal Nerve", "Carries parasympathetic secretomotor fibres from otic ganglion (via IX → tympanic plexus → lesser petrosal → otic ganglion)"],
    ]
    story.append(make_table([], parotid_data, col_widths=[42*mm, 113*mm]))
    story.append(spacer(3))
    story.append(ParotidDiagram())
    story.append(spacer(3))

    # ── Q6 ───────────────────────────────────────────────────────
    story.append(section_header(6, "Where does the parotid duct open? [Dutta 6th/119]"))
    story.append(spacer(2))
    story.append(key_point("Opening", "Into the oral cavity opposite/adjacent to the <b>crown of the upper 2nd molar tooth</b> on the buccal mucosa"))
    story.append(spacer(1))
    story.append(key_point("Course", "Leaves anterior edge of gland → crosses masseter → turns medially at anterior border → passes through buccal fat pad → pierces buccinator → opens into vestibule"))
    story.append(spacer(1))
    story.append(key_point("Length", "~5 cm; also called Stensen's duct"))
    story.append(warning_box("Stensen's duct is palpable across the masseter muscle. Parotid calculi (sialoliths) are LESS common than submandibular calculi because parotid saliva is more serous and less calcium-rich."))
    story.append(spacer(3))

    # ── Q7 ───────────────────────────────────────────────────────
    story.append(section_header(7, "What are the capsules of the parotid gland? [Dutta 6th/116]"))
    story.append(spacer(2))

    cap_data = [
        [Paragraph("<b>Capsule</b>", cell_bold), Paragraph("<b>Origin</b>", cell_bold), Paragraph("<b>Features</b>", cell_bold)],
        ["True capsule (inner)", "Gland's own CT stroma", "Thin, incomplete; invests gland lobules"],
        ["False capsule (outer)", "Investing layer of deep cervical fascia (splits to enclose gland)", "Dense, unyielding – especially superior & posterior; DEFICIENT inferomedially (parotid notch) → deep part communicates with parapharyngeal space"],
    ]
    story.append(make_table([], cap_data, col_widths=[38*mm, 40*mm, 77*mm]))
    story.append(spacer(2))
    story.append(warning_box("The tough, inextensible false capsule is why parotitis is so painful – it cannot expand with the swollen gland."))
    story.append(spacer(3))

    # ── Q8 ───────────────────────────────────────────────────────
    story.append(section_header(8, "Why is parotid swelling painful? How can parotitis lead to orchitis? [Vishram 2nd/112]"))
    story.append(spacer(2))

    story.append(Paragraph("<b>Why Painful:</b>", h1_style))
    for item in [
        "The parotid gland is enclosed in a <b>tough, inextensible fibrous capsule</b> (investing layer of deep cervical fascia)",
        "When the gland swells (infection/inflammation), pressure builds within this rigid compartment",
        "Increased pressure stimulates <b>pain receptors</b> and compresses parotid contents (nerves)",
        "Chewing (masseter contraction) worsens pain by <b>compressing</b> the gland against the capsule",
        "Auriculotemporal nerve transmits pain → temporal region (referred otalgia possible)",
    ]:
        story.append(bullet(item))
    story.append(spacer(2))

    story.append(Paragraph("<b>Parotitis → Orchitis Mechanism (Mumps):</b>", h1_style))
    mech_data = [
        ["Step 1", "Mumps paramyxovirus infects parotid gland epithelium via respiratory droplets → parotitis"],
        ["Step 2", "Virus replicates → enters bloodstream → PRIMARY VIREMIA"],
        ["Step 3", "Secondary viremia → hematogenous spread to distant organs"],
        ["Step 4", "Virus reaches testicular tissue → orchitis (20-30% of post-pubertal males)"],
        ["Step 5", "Inflammation + pressure in tunica albuginea → seminiferous tubule damage"],
        ["Outcome", "Testicular atrophy + potentially infertility if bilateral orchitis (rare: ~1-2%)"],
    ]
    story.append(make_table(["Step", "Event"], mech_data, col_widths=[18*mm, 137*mm]))
    story.append(spacer(2))
    story.append(info_box("⚡ Key: It is HEMATOGENOUS spread, NOT anatomical/lymphatic – the parotid and testis are not directly connected.", bg=LIGHT_GOLD, border=GOLD))
    story.append(spacer(3))

    # ── Q9 + Histo Diagram ───────────────────────────────────────
    story.append(section_header(9, "Histological differences among parotid, submandibular and sublingual glands"))
    story.append(spacer(2))

    histo_data = [
        [Paragraph("<b>Feature</b>", cell_bold), Paragraph("<b>Parotid</b>", cell_bold),
         Paragraph("<b>Submandibular</b>", cell_bold), Paragraph("<b>Sublingual</b>", cell_bold)],
        ["Acini type", "Purely serous", "Mixed (pred. serous ~70%)", "Mixed (pred. mucous ~70%)"],
        ["Serous demilunes", "N/A", "Present (on mucous acini)", "Present but sparse"],
        ["Intercalated ducts", "Long, well-developed", "Shorter", "Virtually ABSENT"],
        ["Striated ducts", "Prominent", "Well developed", "Short/few"],
        ["Excretory duct", "Stensen's (~5 cm)", "Wharton's (5 cm)", "Ducts of Rivinus (×8-20)"],
        ["Fat cells", "Many (↑ with age)", "Fewer", "Fewer"],
        ["Capsule", "Well defined", "Well defined", "Poorly defined"],
        ["Unique feature", "Purely serous; fat lobules", "Serous demilunes on mucous tubules", "No single main duct; opens along sublingual fold"],
    ]
    story.append(make_table([], histo_data, col_widths=[36*mm, 38*mm, 38*mm, 43*mm]))
    story.append(spacer(3))
    story.append(SalivaryHistoDiagram())
    story.append(spacer(3))
    story.append(PageBreak())

    # ── Q10 ──────────────────────────────────────────────────────
    story.append(section_header(10, "Tell me the location and parts of the thyroid gland. [Dutta 6th/134]"))
    story.append(spacer(2))
    story.append(Paragraph("<b>Location:</b>", h1_style))
    for item in [
        "Anterior neck, <b>below and lateral to the thyroid cartilage</b>",
        "Lies in the <b>visceral compartment</b> of the neck (with pharynx, trachea, oesophagus)",
        "Enclosed within the <b>pretracheal fascia</b>",
        "Deep to sternohyoid, sternothyroid and omohyoid muscles",
        "Covers anterolateral surfaces of trachea, cricoid cartilage, lower thyroid cartilage",
    ]:
        story.append(bullet(item))
    story.append(spacer(2))
    story.append(Paragraph("<b>Parts:</b>", h1_style))
    parts_data = [
        ["Right lobe", "Larger of the two lateral lobes"],
        ["Left lobe", "Slightly smaller"],
        ["Isthmus", "Connects two lobes; crosses anterior surface of 2nd and 3rd tracheal rings"],
        ["Pyramidal lobe", "Present in ~50%; finger-like projection from isthmus (usually left); remnant of thyroglossal duct; attached to hyoid by levator glandulae thyroideae"],
    ]
    story.append(make_table(["Part", "Description"], parts_data, col_widths=[35*mm, 120*mm]))
    story.append(spacer(3))

    # ── Q11 + Thyroid Diagram ─────────────────────────────────────
    story.append(section_header(11, "Tell me the blood supply of the thyroid gland. [Dutta 6th/136]"))
    story.append(spacer(2))

    bs_data = [
        [Paragraph("<b>Vessel</b>", cell_bold), Paragraph("<b>Origin/Drain to</b>", cell_bold), Paragraph("<b>Supplies/Notes</b>", cell_bold)],
        ["Superior thyroid artery", "1st branch external carotid A", "Superior pole; ant & post glandular branches"],
        ["Inferior thyroid artery", "Thyrocervical trunk (1st part subclavian A)", "Inferior pole + parathyroid glands (ascending branch)"],
        ["Thyroid ima artery (occasional ~3-10%)", "Brachiocephalic trunk or aortic arch", "Ascends on anterior trachea → isthmus; surgical importance"],
        ["Superior thyroid vein", "→ Internal jugular vein", "Drains area of STA territory"],
        ["Middle thyroid vein", "→ Internal jugular vein", "Short, crosses to IJV directly; no corresponding artery"],
        ["Inferior thyroid vein", "→ Brachiocephalic veins (R&L)", "Crosses trachea – at risk in tracheostomy"],
        ["Lymphatics", "→ Paratracheal nodes → deep cervical (inf.) nodes", "Along internal jugular vein below omohyoid"],
    ]
    story.append(make_table([], bs_data, col_widths=[42*mm, 50*mm, 63*mm]))
    story.append(spacer(3))
    story.append(ThyroidDiagram())
    story.append(spacer(3))

    # ── Q12 ──────────────────────────────────────────────────────
    story.append(section_header(12, "Why are superior and inferior thyroid arteries important to neck surgeons? [Vishram 2nd]"))
    story.append(spacer(2))

    story.append(Paragraph("<b>Superior Thyroid Artery:</b>", h1_style))
    for item in [
        "Runs closely alongside the <b>External Laryngeal Nerve</b> (branch of superior laryngeal N from vagus)",
        "The external laryngeal nerve innervates the <b>cricothyroid muscle</b> – the 'tensor' of vocal cord",
        "Injury during high ligation → loss of high-pitched phonation, fatigue during prolonged speaking",
        "Called <b>'nerve of the opera singer'</b> (Amelita Galli-Curci case)",
        "Artery must be ligated <b>close to the gland</b> (not near its origin from ECA) to protect the nerve",
    ]:
        story.append(bullet(item))
    story.append(spacer(2))

    story.append(Paragraph("<b>Inferior Thyroid Artery:</b>", h1_style))
    for item in [
        "Intimately related to the <b>Recurrent Laryngeal Nerve (RLN)</b>",
        "RLN may pass <b>anterior, posterior, or between branches</b> of the inferior thyroid artery",
        "Injury to RLN → <b>unilateral hoarseness</b>; bilateral → <b>respiratory distress/stridor</b> (adductor paralysis)",
        "Provides sole blood supply to <b>parathyroid glands</b> via ascending branch – accidental ligation → hypoparathyroidism → hypocalcaemia → tetany",
        "Must identify and preserve both RLN and parathyroid supply during thyroidectomy",
    ]:
        story.append(bullet(item))
    story.append(spacer(2))
    story.append(warning_box("Inferior thyroid vein crosses the trachea – at risk during emergency tracheostomy if incision is too high/midline."))
    story.append(spacer(3))

    # ── Q13 ──────────────────────────────────────────────────────
    story.append(section_header(13, "Explain – Why does the thyroid gland move with deglutition? [Vishram 2nd/157]"))
    story.append(spacer(2))
    story.append(info_box(
        "<b>Mechanism:</b> The thyroid gland is enclosed within the <b>pretracheal fascia</b>, "
        "which is attached superiorly to the <b>thyroid and cricoid cartilages of the larynx</b>. "
        "During swallowing, the larynx and trachea are pulled <b>superiorly</b> by the suprahyoid and "
        "thyrohyoid muscles. Since the thyroid is bound to the larynx/trachea via this fascial sheath, "
        "it <b>moves upward with them</b>."
    ))
    story.append(spacer(2))

    move_data = [
        ["Any thyroid swelling (goitre)", "Moves UP on swallowing", "YES"],
        ["Thyroglossal cyst", "Moves UP on swallowing + on tongue protrusion", "YES (pathognomonic)"],
        ["Cervical lymphadenopathy", "Does NOT move on swallowing", "NO"],
        ["Branchial cyst", "Does NOT move on swallowing", "NO"],
        ["Sebaceous cyst", "Does NOT move on swallowing", "NO"],
    ]
    story.append(make_table(["Structure", "Movement", "Moves on swallowing?"], move_data,
                             col_widths=[52*mm, 72*mm, 31*mm]))
    story.append(spacer(3))

    # ── Q14 ──────────────────────────────────────────────────────
    story.append(section_header(14, "Tell me the development of the thyroid gland. [Langman's 12th/292]"))
    story.append(spacer(2))
    dev_steps = [
        ("<b>4th week (24th day)</b>", "Median endodermal thickening on floor of pharynx, between 1st & 2nd pharyngeal pouches → <b>thyroid primordium</b>"),
        ("<b>Foramen cecum</b>", "Site of origin – persists in adults as a small pit on the dorsal surface of tongue, junction of anterior 2/3 and posterior 1/3"),
        ("<b>Descent</b>", "Grows downward as bilobed diverticulum (thyroglossal duct), passing <b>anterior to hyoid bone</b> and thyroid cartilage"),
        ("<b>7th week</b>", "Reaches final position anterior to trachea in root of neck; connected to foramen cecum by thyroglossal duct"),
        ("<b>8th-10th week</b>", "Thyroglossal duct normally <b>involutes and disappears</b>"),
        ("<b>Parafollicular C cells</b>", "Derived from <b>4th pharyngeal pouch / ultimobranchial body</b> (neural crest origin); migrate into thyroid; secrete <b>calcitonin</b>"),
        ("<b>Functional onset</b>", "Thyroid begins secreting colloid ~12th week; iodine uptake starts ~11th week"),
    ]
    for step, text in dev_steps:
        story.append(key_point(step, text))
    story.append(spacer(3))

    # ── Q15 ──────────────────────────────────────────────────────
    story.append(section_header(15, "What is ectopic thyroid? [Dutta 6th/136]"))
    story.append(spacer(2))
    story.append(key_point("Definition", "Thyroid tissue found at an abnormal location due to failed/aberrant migration during embryological development"))
    story.append(spacer(2))

    ect_data = [
        ["Lingual thyroid", "Base of tongue (foramen cecum)", "Most common (90%); may cause dysphagia, dysphonia, dyspnoea"],
        ["Sublingual thyroid", "Above hyoid bone", "Uncommon"],
        ["Intratracheal thyroid", "Tracheal wall", "Rare; causes haemoptysis"],
        ["Mediastinal/substernal", "Superior mediastinum", "Extension of goitre or true ectopic"],
        ["Lateral aberrant thyroid", "Lateral neck nodes", "Usually = lymph node metastasis of well-diff. thyroid Ca"],
        ["Along thyroglossal tract", "Anywhere between base of tongue and neck", "Associated with thyroglossal duct remnants"],
    ]
    story.append(make_table(["Type", "Location", "Notes"], ect_data, col_widths=[38*mm, 42*mm, 75*mm]))
    story.append(spacer(2))
    story.append(warning_box("ALWAYS perform radioiodine (Tc-99m) scan BEFORE removing a lingual/ectopic thyroid mass – it may be the ONLY functioning thyroid tissue in the patient."))
    story.append(spacer(3))

    # ── Q16 + Thyroglossal Diagram ───────────────────────────────
    story.append(section_header(16, "What is a thyroglossal cyst? [Langman's 12th/292]"))
    story.append(spacer(2))
    story.append(key_point("Definition", "A cystic remnant of the thyroglossal duct that forms when the duct fails to involute after thyroid descent"))
    story.append(spacer(2))
    story.append(Paragraph("<b>Key Features:</b>", h1_style))
    tg_features = [
        "Most common <b>congenital neck mass</b> in children",
        "Midline or just left of midline (pyramidal lobe tends left)",
        "Most common site: <b>below hyoid bone (infrahyoid) – 65%</b>",
        "Surface is smooth, soft, fluctuant",
        "<b>Moves UPWARD on both swallowing AND tongue protrusion</b> – pathognomonic (attached to foramen cecum via duct remnant)",
        "May get infected → discharge via thyroglossal fistula",
        "Rarely: carcinoma (papillary type) may arise within the cyst (~1%)",
    ]
    for f in tg_features:
        story.append(bullet(f))
    story.append(spacer(2))
    story.append(info_box("<b>Sistrunk's Operation (treatment):</b> Excision of cyst + central part of hyoid bone + complete tract up to foramen cecum. Removal of hyoid prevents recurrence (duct passes through/around hyoid)."))
    story.append(spacer(3))
    story.append(ThyroglosalDiagram())
    story.append(spacer(3))
    story.append(PageBreak())

    # ── Q17 ──────────────────────────────────────────────────────
    story.append(section_header(17, "Tell me the location of the parathyroid gland. [Dutta 6th/139]"))
    story.append(spacer(2))
    story.append(key_point("Number", "4 glands – 2 superior + 2 inferior (may rarely have 3-6)"))
    story.append(key_point("General", "Located on the posterior surface (deep surface) of the lateral lobes of the thyroid gland, within the thyroid capsule but outside the parenchyma"))
    story.append(spacer(2))

    pt_data = [
        [Paragraph("<b>Gland</b>", cell_bold), Paragraph("<b>Embryological origin</b>", cell_bold),
         Paragraph("<b>Position</b>", cell_bold), Paragraph("<b>Constancy</b>", cell_bold)],
        ["Superior parathyroid (×2)", "4th pharyngeal pouch", "Junction of upper 1/3 & lower 2/3 of posterior thyroid lobe, near entry of inferior thyroid artery", "More constant"],
        ["Inferior parathyroid (×2)", "3rd pharyngeal pouch (with thymus)", "Near inferior pole of thyroid, thyrothymic ligament, or upper mediastinum", "MORE variable; anywhere carotid bifurcation to mediastinum"],
    ]
    story.append(make_table([], pt_data, col_widths=[38*mm, 36*mm, 60*mm, 21*mm]))
    story.append(spacer(2))
    story.append(key_point("Blood supply", "Inferior thyroid artery (ascending branch) supplies both superior and inferior parathyroids predominantly"))
    story.append(warning_box("The 3rd pouch descends further than 4th pouch (paradox): inferior parathyroid (from 3rd pouch) ends up below the superior parathyroid (from 4th pouch)."))
    story.append(spacer(3))

    # ── Q18 ──────────────────────────────────────────────────────
    story.append(section_header(18, "Tell me the location of the pituitary gland. [Dutta 6th/177]"))
    story.append(spacer(2))
    pit_data = [
        ["Bone", "Sella turcica (hypophyseal fossa) of the sphenoid bone"],
        ["Cranial fossa", "Middle cranial fossa, at base of brain"],
        ["Superior", "Optic chiasma (above) – tumour → bitemporal hemianopia by upward pressure"],
        ["Lateral (both sides)", "Cavernous sinuses – contain CN III, IV, V1, V2, VI and internal carotid artery"],
        ["Superior covering", "Diaphragma sellae (dural fold) – pituitary stalk passes through its aperture"],
        ["Connected to", "Hypothalamus via pituitary stalk (infundibulum)"],
        ["Size/weight", "~8 × 12 × 6 mm; weight ~500–600 mg (↑ in pregnancy up to 1g)"],
    ]
    story.append(make_table(["Relation", "Structure"], pit_data, col_widths=[42*mm, 113*mm]))
    story.append(spacer(3))

    # ── Q19 ──────────────────────────────────────────────────────
    story.append(section_header(19, "What is the hypothalamo-hypophyseal tract? [Snell's Neuro 7th/388]"))
    story.append(spacer(2))
    story.append(key_point("Definition",
        "A bundle of UNMYELINATED nerve axons running from the hypothalamus → posterior pituitary (neurohypophysis)"))
    story.append(spacer(2))

    tract_data = [
        ["Cell bodies", "Magnocellular neurons in <b>supraoptic nucleus</b> (mainly ADH/vasopressin) and <b>paraventricular nucleus</b> (mainly oxytocin) of hypothalamus"],
        ["Axons", "Travel through infundibular stalk as the hypothalamo-hypophyseal tract"],
        ["Terminals", "Axon terminals in the pars nervosa (posterior pituitary) – bulbous endings called <b>Herring bodies</b>"],
        ["Hormones", "<b>ADH (vasopressin)</b> – water reabsorption in collecting ducts, vasoconstriction; <b>Oxytocin</b> – uterine contractions, milk ejection (Ferguson reflex)"],
        ["Type of secretion", "NEUROSECRETION – NOT portal system; hormones travel down axons as neurosecretory granules"],
        ["Release", "Into fenestrated capillaries of posterior pituitary → systemic circulation"],
    ]
    story.append(make_table(["Component", "Details"], tract_data, col_widths=[30*mm, 125*mm]))
    story.append(spacer(3))

    # ── Q20 ──────────────────────────────────────────────────────
    story.append(section_header(20, "What is the hypothalamo-hypophyseal portal system? [Snell's Neuro 7th/389]"))
    story.append(spacer(2))
    story.append(key_point("Definition",
        "A portal circulation (capillary-to-capillary system) connecting hypothalamus to the ANTERIOR pituitary (adenohypophysis)"))
    story.append(spacer(2))

    portal_steps = [
        ("Primary capillary plexus", "Hypothalamic neurons (arcuate, periventricular nuclei) release releasing/inhibiting hormones into capillaries in the <b>median eminence</b>"),
        ("Portal vessels", "Hypophyseal portal veins run down the pituitary stalk"),
        ("Secondary capillary plexus", "Portal veins break into a secondary plexus in the anterior pituitary – fenestrated capillaries"),
        ("Action", "Releasing hormones act on specific anterior pituitary cells to stimulate (or inhibit) release of their hormones"),
        ("Hormones released", "TRH → TSH; GnRH → LH, FSH; GHRH/Somatostatin → GH; CRH → ACTH; Dopamine → ↓Prolactin"),
        ("Clinical significance", "Stalk section → loss of anterior pituitary function (all except Prolactin which ↑ due to loss of dopamine inhibition)"),
    ]
    story.append(make_table(["Component", "Details"], portal_steps, col_widths=[38*mm, 117*mm]))
    story.append(spacer(3))

    # ── Q21 + Pituitary Diagram ───────────────────────────────────
    story.append(section_header(21, "Why is BBB absent in the posterior pituitary gland?"))
    story.append(spacer(2))
    story.append(info_box(
        "<b>Blood Brain Barrier (BBB):</b> Formed by tight junctions between cerebral capillary endothelial cells + pericytes + astrocyte end-feet. "
        "It prevents free passage of large molecules between blood and brain tissue."
    ))
    story.append(spacer(2))

    story.append(Paragraph("<b>Reasons BBB is absent in posterior pituitary:</b>", h1_style))
    bbb_reasons = [
        "<b>Neurohaemal organ function</b> – The posterior pituitary is a site of neurohormone (ADH, oxytocin) release directly into bloodstream; a BBB would block this",
        "<b>Fenestrated capillaries</b> – Unlike CNS capillaries, posterior pituitary capillaries have PORES (fenestrations) allowing free passage of large peptide hormones",
        "<b>Circumventricular organ (CVO)</b> – Posterior pituitary is one of 7 CVOs that lack BBB to allow blood-brain communication",
        "<b>No astrocyte end-feet</b> covering these capillaries (different from rest of CNS)",
    ]
    for r in bbb_reasons:
        story.append(bullet(r))
    story.append(spacer(2))

    cvo_data = [
        ["Area postrema", "Vomiting centre; detects blood-borne toxins"],
        ["Subfornical organ", "Detects angiotensin II → regulates thirst & ADH release"],
        ["OVLT (organum vasculosum lamina terminalis)", "Detects osmolarity changes, cytokines (fever)"],
        ["Median eminence", "Releases hypothalamic hormones into portal blood"],
        ["Posterior pituitary (neurohypophysis)", "Releases ADH and oxytocin"],
        ["Subcommissural organ", "Secretes glycoproteins into CSF"],
        ["Pineal gland", "Releases melatonin into bloodstream"],
    ]
    story.append(Paragraph("<b>The 7 Circumventricular Organs (CVOs) – all lack BBB:</b>", h1_style))
    story.append(make_table(["CVO", "Function"], cvo_data, col_widths=[75*mm, 80*mm]))
    story.append(spacer(2))
    story.append(warning_box(
        "Posterior pituitary = Pars nervosa + Infundibular stalk + Median eminence. "
        "It secretes ADH (water reabsorption, vasoconstriction) and Oxytocin (uterine contraction, milk ejection). "
        "SIADH (↑ADH) = hyponatremia; Diabetes Insipidus (↓ADH) = polyuria + polydipsia."
    ))
    story.append(spacer(3))
    story.append(PituitaryDiagram())
    story.append(spacer(3))
    story.append(PageBreak())

    # ── QUICK REVISION SUMMARY ────────────────────────────────────
    summary_title = Paragraph("QUICK REVISION SUMMARY TABLE", S("Normal",
        fontSize=14, textColor=WHITE, fontName="Helvetica-Bold",
        alignment=TA_CENTER, leading=18))
    title_table = Table([[summary_title]], colWidths=[PAGE_W - 2*MARGIN])
    title_table.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), NAVY),
        ("TOPPADDING", (0,0), (-1,-1), 10),
        ("BOTTOMPADDING", (0,0), (-1,-1), 10),
        ("ROUNDEDCORNERS", [5]),
    ]))
    story.append(title_table)
    story.append(spacer(3))

    summary_data = [
        [Paragraph("<b>Q</b>", cell_bold), Paragraph("<b>Topic</b>", cell_bold), Paragraph("<b>One-liner Key Answer</b>", cell_bold)],
        ["1", "Gland names", "Pituitary, Thyroid, Parathyroid, Pineal + Parotid, Submandibular, Sublingual + Minor glands"],
        ["2", "Major salivary glands", "Parotid (serous/Stensen's), Submandibular (mixed/Wharton's), Sublingual (mucous/Rivinus)"],
        ["3", "Minor salivary glands", "Labial, Buccal, Palatine, Lingual (Blandin-Nuhn, von Ebner), Molar, Glossopalatine"],
        ["4", "Endocrine neck glands", "Pituitary, Thyroid, Parathyroid, Hypothalamus, Pineal"],
        ["5", "Parotid contents", "Facial N VII + Ext Carotid A + Retromandibular V + Parotid LN + Auriculotemporal N"],
        ["6", "Parotid duct opening", "Opposite crown of upper 2nd molar tooth (Stensen's duct ~5cm, pierces buccinator)"],
        ["7", "Parotid capsules", "True (own CT) + False (investing deep cervical fascia – tough, inextensible)"],
        ["8", "Why painful/orchitis", "Tight inextensible capsule → pressure pain; Orchitis via hematogenous spread of mumps virus"],
        ["9", "Histo differences", "Parotid=serous; Submandibular=mixed serous(+demilunes); Sublingual=mixed mucous; ↓ducts sublingual"],
        ["10", "Thyroid parts/location", "Visceral compartment neck; Right lobe + Left lobe + Isthmus (2nd-3rd tracheal rings) + Pyramidal lobe"],
        ["11", "Thyroid blood supply", "Sup. thyroid A (ECA) + Inf. thyroid A (thyrocervical trunk); 3 venous pairs; paratracheal LN"],
        ["12", "Surgical importance", "STA → Ext laryngeal N (cricothyroid); ITA → RLN (hoarseness) + parathyroid supply"],
        ["13", "Moves on swallowing", "Pretracheal fascia binds thyroid to larynx/trachea → moves superiorly with deglutition"],
        ["14", "Thyroid development", "Median endodermal outgrowth, foramen cecum (4th wk) → descends → 7th wk final position; C cells from 4th pouch"],
        ["15", "Ectopic thyroid", "Failed descent; lingual (most common); SCAN before removal – may be only thyroid tissue"],
        ["16", "Thyroglossal cyst", "Thyroglossal duct remnant; midline; infrahyoid (65%); moves on swallowing + tongue protrusion; Sistrunk op."],
        ["17", "Parathyroid location", "Posterior thyroid lobe; Superior (from 4th pouch) + Inferior (from 3rd pouch); ITA supply"],
        ["18", "Pituitary location", "Sella turcica of sphenoid; middle cranial fossa; Lat = cavernous sinus; Sup = optic chiasma"],
        ["19", "Hypothalamo-hypophyseal tract", "Axons SON/PVN → posterior pituitary; ADH + oxytocin; Herring bodies; neurosecretion"],
        ["20", "Hypothalamo-hypophyseal portal", "Portal vessels median eminence → ant. pituitary; releasing hormones; stalk section → ↑prolactin only"],
        ["21", "BBB absent post. pituitary", "Neurohaemal organ; fenestrated capillaries; CVO (one of 7); needed for ADH/OT release"],
    ]
    story.append(make_table([], summary_data, col_widths=[8*mm, 45*mm, 102*mm]))
    story.append(spacer(4))

    # Mnemonic box
    story.append(info_box(
        "<b>🧠 Master Mnemonics</b><br/>"
        "Parotid contents: <b>S-T-A-R-P</b> = Skin/Superficial fascia → Trunk of Facial N → Artery (Ext Carotid) → Retromandibular V → Parotid LN<br/>"
        "5 branches Facial N: <b>Two Zebras Bit My Cat</b> = Temporal, Zygomatic, Buccal, Marginal mandibular, Cervical<br/>"
        "Thyroid blood supply arteries: <b>SIT</b> = Superior thyroid + Inferior thyroid + (Thyroid ima)<br/>"
        "CVOs: <b>OVLT-MSPA-P</b> = OVLT, ME, SFO, Pineal, AP, SCO, Posterior pituitary<br/>"
        "Pharyngeal pouches: 1st→Middle ear; 2nd→Palatine tonsil; 3rd→Inferior PTH+Thymus; 4th→Superior PTH+C cells",
        bg=LIGHT_PURPLE, border=PURPLE
    ))

    doc.build(story, onFirstPage=on_page, onLaterPages=on_page)
    print("PDF built successfully!")

build_pdf("/tmp/workspace/glands-viva/Glands_Head_Neck_Viva.pdf")

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/glands-viva/make_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/glands-viva/make_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/glands-viva/make_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/glands-viva/make_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/glands-viva/make_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/glands-viva/make_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/glands-viva/make_pdf.py'