diff --git a/carousel/diff-diff-v26-carousel.pdf b/carousel/diff-diff-v26-carousel.pdf
new file mode 100644
index 0000000..4183a3a
Binary files /dev/null and b/carousel/diff-diff-v26-carousel.pdf differ
diff --git a/carousel/generate_v26_pdf.py b/carousel/generate_v26_pdf.py
new file mode 100644
index 0000000..6f45513
--- /dev/null
+++ b/carousel/generate_v26_pdf.py
@@ -0,0 +1,1072 @@
+#!/usr/bin/env python3
+"""Generate LinkedIn carousel PDF for diff-diff v2.6 release."""
+
+import math
+import os
+import tempfile
+from pathlib import Path
+
+import matplotlib
+matplotlib.use("Agg")
+import matplotlib.pyplot as plt  # noqa: E402
+import numpy as np  # noqa: E402
+from PIL import Image as PILImage  # noqa: E402
+
+from fpdf import FPDF  # noqa: E402
+
+# Use Computer Modern math font (LaTeX-like)
+plt.rcParams["mathtext.fontset"] = "cm"
+
+# LinkedIn carousel dimensions (4:5 aspect ratio)
+WIDTH = 270  # mm
+HEIGHT = 337.5  # mm
+
+# Colors - Light theme with violet accent
+MID_BLUE = (59, 130, 246)  # #3b82f6
+NAVY = (15, 23, 42)  # #0f172a
+WHITE = (255, 255, 255)
+RED = (220, 38, 38)  # #dc2626
+GREEN = (22, 163, 74)  # #16a34a
+GRAY = (100, 116, 139)  # #64748b
+LIGHT_GRAY = (148, 163, 184)  # #94a3b8
+VIOLET = (124, 58, 237)  # #7c3aed - v2.6 accent
+DARK_SLATE = (30, 41, 59)  # #1e293b - code block bg
+
+VIOLET_TINT = (245, 240, 255)  # callout background
+
+# Hex colors for matplotlib
+NAVY_HEX = "#0f172a"
+VIOLET_HEX = "#7c3aed"
+VIOLET_LIGHT_HEX = "#c4b5fd"
+
+
+class CarouselV26PDF(FPDF):
+    def __init__(self):
+        super().__init__(orientation="P", unit="mm", format=(WIDTH, HEIGHT))
+        self.set_auto_page_break(False)
+        self._temp_files = []
+
+    def cleanup(self):
+        """Remove temporary image files."""
+        for f in self._temp_files:
+            try:
+                os.unlink(f)
+            except OSError:
+                pass
+
+    # ── Equation Rendering ────────────────────────────────────────────
+
+    def _render_equations(self, latex_lines, fontsize=26):
+        """Render one or more LaTeX equations to a single PNG image.
+
+        Args:
+            latex_lines: list of LaTeX math strings (each wrapped in $...$)
+            fontsize: matplotlib font size
+
+        Returns:
+            (path, pixel_width, pixel_height)
+        """
+        n = len(latex_lines)
+        fig_h = max(0.7, 0.55 * n + 0.15)
+        fig = plt.figure(figsize=(10, fig_h))
+
+        for i, line in enumerate(latex_lines):
+            y_frac = 1.0 - (2 * i + 1) / (2 * n)
+            fig.text(
+                0.5, y_frac, line,
+                fontsize=fontsize, ha="center", va="center",
+                color=NAVY_HEX,
+            )
+
+        fig.patch.set_alpha(0)
+        fd, path = tempfile.mkstemp(suffix=".png")
+        os.close(fd)
+        fig.savefig(path, dpi=250, bbox_inches="tight", pad_inches=0.06,
+                    transparent=True)
+        plt.close(fig)
+
+        with PILImage.open(path) as img:
+            pw, ph = img.size
+
+        self._temp_files.append(path)
+        return path, pw, ph
+
+    def _place_equation(self, path, pw, ph, box_x, _box_y, box_w,
+                        content_top, content_bottom):
+        """Place an equation image centered in a region of a box."""
+        max_w = box_w * 0.82
+        aspect = ph / pw
+        display_w = max_w
+        display_h = display_w * aspect
+
+        # Shrink if too tall for the available space
+        avail_h = content_bottom - content_top
+        if display_h > avail_h:
+            display_h = avail_h
+            display_w = display_h / aspect
+
+        eq_x = box_x + (box_w - display_w) / 2
+        eq_y = content_top + (avail_h - display_h) / 2
+        self.image(path, eq_x, eq_y, display_w)
+
+    # ── Dose-Response Figure ──────────────────────────────────────────
+
+    def _render_dose_response_figure(self):
+        """Render illustrative ATT(d) dose-response curve to PNG.
+
+        Returns:
+            (path, pixel_width, pixel_height)
+        """
+        d = np.linspace(0.5, 10, 200)
+        att = 1 + 2 * np.log(d)
+        # Widening SE at extremes
+        se = 0.3 + 0.15 * (d - 5) ** 2 / 25 + 0.1 * np.exp(-d)
+        upper = att + 1.96 * se
+        lower = att - 1.96 * se
+
+        fig, ax = plt.subplots(figsize=(8, 4.5))
+
+        # Confidence band
+        ax.fill_between(d, lower, upper, alpha=0.25, color=VIOLET_LIGHT_HEX,
+                         label="95% CI")
+        # ATT(d) curve
+        ax.plot(d, att, color=VIOLET_HEX, linewidth=2.5, label="ATT(d)")
+        # Zero line
+        ax.axhline(0, color=NAVY_HEX, linewidth=0.8, linestyle="--", alpha=0.5)
+
+        ax.set_xlabel("Dose (d)", fontsize=13, color=NAVY_HEX)
+        ax.set_ylabel("ATT(d)", fontsize=13, color=NAVY_HEX)
+        ax.tick_params(colors=NAVY_HEX, labelsize=11)
+        for spine in ax.spines.values():
+            spine.set_color(NAVY_HEX)
+            spine.set_linewidth(0.8)
+        ax.set_facecolor("white")
+        fig.patch.set_facecolor("white")
+        ax.legend(fontsize=11, framealpha=0.9)
+
+        fd, path = tempfile.mkstemp(suffix=".png")
+        os.close(fd)
+        fig.savefig(path, dpi=200, bbox_inches="tight", pad_inches=0.1,
+                    facecolor="white")
+        plt.close(fig)
+
+        with PILImage.open(path) as img:
+            pw, ph = img.size
+
+        self._temp_files.append(path)
+        return path, pw, ph
+
+    # ── Helper Methods ────────────────────────────────────────────────
+
+    def add_connector_graphic(self, position="right"):
+        """Add decorative connector graphic to bottom corner."""
+        if position == "right":
+            cx = WIDTH + 20
+            cy = HEIGHT - 40
+        else:
+            cx = -20
+            cy = HEIGHT - 40
+
+        self.set_draw_color(*MID_BLUE)
+        for i, radius in enumerate([60, 80, 100]):
+            self.set_line_width(2.5 - i * 0.5)
+            segments = 30
+            if position == "right":
+                start_angle = math.pi * 0.5
+                end_angle = math.pi * 1.0
+            else:
+                start_angle = 0
+                end_angle = math.pi * 0.5
+
+            for j in range(segments):
+                t1 = start_angle + (end_angle - start_angle) * j / segments
+                t2 = start_angle + (end_angle - start_angle) * (j + 1) / segments
+                x1 = cx + radius * math.cos(t1)
+                y1 = cy + radius * math.sin(t1)
+                x2 = cx + radius * math.cos(t2)
+                y2 = cy + radius * math.sin(t2)
+                self.line(x1, y1, x2, y2)
+
+        self.set_fill_color(*MID_BLUE)
+        if position == "right":
+            dot_positions = [(35, HEIGHT - 60), (50, HEIGHT - 45), (30, HEIGHT - 35)]
+        else:
+            dot_positions = [
+                (WIDTH - 35, HEIGHT - 60),
+                (WIDTH - 50, HEIGHT - 45),
+                (WIDTH - 30, HEIGHT - 35),
+            ]
+        for i, (dx, dy) in enumerate(dot_positions):
+            dot_radius = 3 - i * 0.5
+            self.ellipse(
+                dx - dot_radius, dy - dot_radius, dot_radius * 2, dot_radius * 2, "F"
+            )
+
+    def light_gradient_background(self):
+        """Draw light gradient background (top #e1f0ff fading to white)."""
+        steps = 50
+        for i in range(steps):
+            ratio = i / steps
+            r = int(225 + (255 - 225) * ratio)
+            g = int(240 + (255 - 240) * ratio)
+            b = 255
+            self.set_fill_color(r, g, b)
+            y = i * HEIGHT / steps
+            self.rect(0, y, WIDTH, HEIGHT / steps + 1, "F")
+
+    def add_footer(self):
+        """Add footer with logo."""
+        self.set_xy(0, HEIGHT - 25)
+        self.set_font("Helvetica", "B", 14)
+        self.set_text_color(*GRAY)
+        self.cell(WIDTH, 10, "diff-diff", align="C")
+
+    def centered_text(self, y, text, size=28, bold=True, color=NAVY):
+        """Add centered text."""
+        self.set_xy(0, y)
+        self.set_font("Helvetica", "B" if bold else "", size)
+        self.set_text_color(*color)
+        self.cell(WIDTH, size * 0.5, text, align="C")
+
+    def add_list_item(self, y, icon, text, icon_color, text_size=22):
+        """Add a list item with icon."""
+        margin = 50
+        self.set_xy(margin, y)
+        self.set_font("Helvetica", "B", text_size + 2)
+        self.set_text_color(*icon_color)
+        self.cell(25, 12, icon, align="C")
+        self.set_text_color(*NAVY)
+        self.set_font("Helvetica", "", text_size)
+        self.cell(WIDTH - margin * 2 - 25, 12, text)
+
+    def draw_split_logo(self, y, size=18):
+        """Draw the split-color diff-diff logo."""
+        self.set_xy(0, y)
+        self.set_font("Helvetica", "B", size)
+        self.set_text_color(*NAVY)
+        self.cell(WIDTH / 2 - 5, 10, "diff", align="R")
+        self.set_text_color(*MID_BLUE)
+        self.cell(10, 10, "-", align="C")
+        self.set_text_color(*NAVY)
+        self.cell(WIDTH / 2 - 5, 10, "diff", align="L")
+
+    # ── Slide 1: Hook ─────────────────────────────────────────────────
+
+    def slide_hook(self):
+        """Slide 1: What if treatment isn't binary?"""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.draw_split_logo(55, size=60)
+        self.centered_text(120, "v2.6", size=50, color=VIOLET)
+
+        self.centered_text(170, "What if treatment", size=26)
+        self.centered_text(193, "isn't binary?", size=26)
+
+        teasers = [
+            "Dose-response curves for continuous treatments",
+            "Callaway, Goodman-Bacon & Sant'Anna (2024)",
+            "B-spline smoothing with analytical SEs",
+        ]
+        y_start = 230
+        for i, teaser in enumerate(teasers):
+            self.set_xy(0, y_start + i * 22)
+            self.set_font("Helvetica", "", 17)
+            self.set_text_color(*GRAY)
+            self.cell(WIDTH, 10, teaser, align="C")
+
+        self.add_footer()
+
+    # ── Slide 2: The Problem ──────────────────────────────────────────
+
+    def slide_problem(self):
+        """Slide 2: Binary DiD Loses Information."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(30, "Binary DiD", size=38)
+        self.centered_text(63, "Loses Information", size=38, color=RED)
+
+        # Visual comparison: bars showing binarization vs continuous dose
+        margin = 40
+        panel_y = 105
+        panel_w = (WIDTH - margin * 3) / 2
+        bar_h = 14
+        bar_gap = 6
+        n_bars = 5
+
+        # Dose values for illustration (varying widths)
+        doses = [0.3, 0.7, 0.5, 0.9, 0.45]
+
+        # Left panel: Binary — all bars collapsed to same "Treated" width
+        left_x = margin
+        self.set_font("Helvetica", "B", 14)
+        self.set_text_color(*NAVY)
+        self.set_xy(left_x, panel_y - 16)
+        self.cell(panel_w, 10, "Binary: D = {0, 1}", align="C")
+
+        for i in range(n_bars):
+            y = panel_y + i * (bar_h + bar_gap)
+            bar_w = panel_w * 0.85  # all same width (binarized)
+            self.set_fill_color(*RED)
+            self.rect(left_x, y, bar_w, bar_h, "F")
+
+        # "Treated" label below
+        self.set_font("Helvetica", "I", 11)
+        self.set_text_color(*RED)
+        bars_bottom = panel_y + n_bars * (bar_h + bar_gap)
+        self.set_xy(left_x, bars_bottom - 2)
+        self.cell(panel_w, 10, "All collapsed to \"Treated\"", align="C")
+
+        # Right panel: Continuous — bars proportional to dose
+        right_x = margin * 2 + panel_w
+        self.set_font("Helvetica", "B", 14)
+        self.set_text_color(*NAVY)
+        self.set_xy(right_x, panel_y - 16)
+        self.cell(panel_w, 10, "Continuous: D > 0", align="C")
+
+        # Violet gradient for varying doses
+        for i, dose in enumerate(doses):
+            y = panel_y + i * (bar_h + bar_gap)
+            bar_w = panel_w * dose * 0.95
+            # Darker violet for higher dose
+            intensity = 0.4 + 0.6 * dose
+            r = int(124 * intensity + 245 * (1 - intensity))
+            g = int(58 * intensity + 240 * (1 - intensity))
+            b = int(237 * intensity + 255 * (1 - intensity))
+            self.set_fill_color(r, g, b)
+            self.rect(right_x, y, bar_w, bar_h, "F")
+
+        # "Dose preserved" label below
+        self.set_font("Helvetica", "I", 11)
+        self.set_text_color(*VIOLET)
+        self.set_xy(right_x, bars_bottom - 2)
+        self.cell(panel_w, 10, "Dose variation preserved", align="C")
+
+        # Callout box
+        callout_y = bars_bottom + 14
+        callout_margin = 35
+        callout_w = WIDTH - callout_margin * 2
+        self.set_fill_color(*VIOLET_TINT)
+        self.set_draw_color(*VIOLET)
+        self.set_line_width(0.8)
+        self.rect(callout_margin, callout_y, callout_w, 34, "DF")
+        self.set_xy(callout_margin + 8, callout_y + 5)
+        self.set_font("Helvetica", "B", 14)
+        self.set_text_color(*VIOLET)
+        self.multi_cell(
+            callout_w - 16, 10,
+            "TWFE with a continuous treatment is biased --\n"
+            "negative weights, contamination, and scale dependence.",
+            align="C",
+        )
+
+        # Gray annotations
+        ann_y = callout_y + 42
+        self.centered_text(
+            ann_y,
+            "Binarizing discards the dose-response relationship entirely",
+            size=13, bold=False, color=GRAY,
+        )
+        self.centered_text(
+            ann_y + 16,
+            "You need level effects AND marginal effects",
+            size=13, bold=False, color=GRAY,
+        )
+
+        self.add_footer()
+
+    # ── Slide 3: The Solution ─────────────────────────────────────────
+
+    def slide_solution(self):
+        """Slide 3: Continuous DiD — the three-step procedure."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(30, "Continuous DiD", size=36, color=NAVY)
+
+        # Citation
+        self.set_xy(0, 65)
+        self.set_font("Helvetica", "I", 15)
+        self.set_text_color(*GRAY)
+        self.cell(
+            WIDTH, 8,
+            "Callaway, Goodman-Bacon & Sant'Anna (2024)  |  NBER WP 32117",
+            align="C",
+        )
+
+        # Three numbered step boxes
+        margin = 35
+        box_width = WIDTH - margin * 2
+        box_height = 42
+        circle_r = 14
+        step_y_start = 95
+        total_step_unit = 60
+
+        steps = [
+            "Compute outcome changes relative to control group mean",
+            "Fit B-spline regression of demeaned outcomes on dose",
+            "Evaluate ATT(d) level effects and ACRT(d) marginal effects",
+        ]
+
+        for i, step_text in enumerate(steps):
+            y = step_y_start + i * total_step_unit
+
+            # Step number circle
+            circle_x = margin + circle_r
+            circle_y = y + box_height / 2
+
+            self.set_fill_color(*VIOLET)
+            self.ellipse(
+                circle_x - circle_r, circle_y - circle_r,
+                circle_r * 2, circle_r * 2, "F",
+            )
+            self.set_xy(circle_x - circle_r, circle_y - 6)
+            self.set_font("Helvetica", "B", 18)
+            self.set_text_color(*WHITE)
+            self.cell(circle_r * 2, 12, str(i + 1), align="C")
+
+            # Step text box
+            text_x = margin + circle_r * 2 + 10
+            text_width = box_width - circle_r * 2 - 10
+
+            self.set_fill_color(*WHITE)
+            self.set_draw_color(*VIOLET)
+            self.set_line_width(0.8)
+            self.rect(text_x, y, text_width, box_height, "DF")
+
+            self.set_font("Helvetica", "", 15)
+            self.set_text_color(*NAVY)
+            self.set_xy(text_x + 10, y + (box_height - 10) / 2)
+            self.cell(text_width - 20, 10, step_text)
+
+            # Downward arrow between steps (except after last)
+            if i < len(steps) - 1:
+                arrow_x = margin + circle_r
+                arrow_top = y + box_height + 2
+                arrow_bottom = y + total_step_unit - 2
+                self.set_draw_color(*VIOLET)
+                self.set_line_width(1.2)
+                self.line(arrow_x, arrow_top, arrow_x, arrow_bottom)
+                # Arrowhead
+                head_size = 5
+                self.line(
+                    arrow_x - head_size, arrow_bottom - head_size,
+                    arrow_x, arrow_bottom,
+                )
+                self.line(
+                    arrow_x + head_size, arrow_bottom - head_size,
+                    arrow_x, arrow_bottom,
+                )
+
+        # Footer text
+        footer_y = step_y_start + 3 * total_step_unit + 2
+        self.centered_text(
+            footer_y,
+            "From binary to the full dose-response curve.",
+            size=15, bold=False, color=GRAY,
+        )
+
+        self.add_footer()
+
+    # ── Slide 4: The Math ─────────────────────────────────────────────
+
+    def slide_math(self):
+        """Slide 4: Three equation boxes — B-spline OLS, ATT(d), ACRT(d)."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(30, "The Math", size=38)
+        self.centered_text(63, "Three targets, one estimation", size=18,
+                           bold=False, color=GRAY)
+
+        margin = 30
+        box_w = WIDTH - margin * 2
+        badge_w = 80
+        badge_h = 18
+
+        # Pre-render equations
+        eq1_path, eq1_pw, eq1_ph = self._render_equations(
+            [r"$\Delta\tilde{Y}_i = \psi^K(D_i)'\beta + \varepsilon_i$"]
+        )
+        eq2_path, eq2_pw, eq2_ph = self._render_equations(
+            [r"$\mathrm{ATT}(d) = \psi^K(d)'\hat{\beta}$"]
+        )
+        eq3_path, eq3_pw, eq3_ph = self._render_equations(
+            [r"$\mathrm{ACRT}(d) = \frac{\partial \psi^K(d)}{\partial d}"
+             r" \cdot \hat{\beta}$"]
+        )
+
+        boxes = [
+            {
+                "badge": "B-Spline OLS",
+                "eq": (eq1_path, eq1_pw, eq1_ph),
+                "annotation": "(demeaned outcome ~ B-spline basis of dose)",
+                "height": 50,
+            },
+            {
+                "badge": "ATT(d)",
+                "eq": (eq2_path, eq2_pw, eq2_ph),
+                "annotation": "(level effect: total impact at dose d)",
+                "height": 50,
+            },
+            {
+                "badge": "ACRT(d)",
+                "eq": (eq3_path, eq3_pw, eq3_ph),
+                "annotation": "(marginal effect: response per unit of dose)",
+                "height": 55,
+            },
+        ]
+
+        y_cursor = 88
+        box_gap = 10
+
+        for box in boxes:
+            bh = box["height"]
+
+            # White box with violet border
+            self.set_fill_color(*WHITE)
+            self.set_draw_color(*VIOLET)
+            self.set_line_width(0.8)
+            self.rect(margin, y_cursor, box_w, bh, "DF")
+
+            # Violet badge overlapping top edge
+            badge_x = margin + 8
+            badge_y = y_cursor - badge_h / 2
+            self.set_fill_color(*VIOLET)
+            self.rect(badge_x, badge_y, badge_w, badge_h, "F")
+            self.set_xy(badge_x, badge_y + 3)
+            self.set_font("Helvetica", "B", 11)
+            self.set_text_color(*WHITE)
+            self.cell(badge_w, 12, box["badge"], align="C")
+
+            # Determine content region
+            content_top = y_cursor + badge_h / 2 + 2
+            if box["annotation"]:
+                ann_y = y_cursor + bh - 14
+                content_bottom = ann_y - 2
+            else:
+                content_bottom = y_cursor + bh - 6
+
+            # Place equation image
+            eq_path, eq_pw, eq_ph = box["eq"]
+            self._place_equation(
+                eq_path, eq_pw, eq_ph,
+                margin, y_cursor, box_w,
+                content_top, content_bottom,
+            )
+
+            # Annotation text
+            if box["annotation"]:
+                self.set_xy(margin, ann_y)
+                self.set_font("Helvetica", "I", 12)
+                self.set_text_color(*GRAY)
+                self.cell(box_w, 10, box["annotation"], align="C")
+
+            y_cursor += bh + box_gap
+
+        # Below boxes
+        self.centered_text(
+            y_cursor + 2,
+            "Influence-function SEs + multiplier bootstrap",
+            size=14, bold=True, color=VIOLET,
+        )
+
+        self.add_footer()
+
+    # ── Slide 5: Dose-Response Curve ──────────────────────────────────
+
+    def slide_dose_response(self):
+        """Slide 5: Visual centerpiece — matplotlib dose-response figure."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(25, "Dose-Response", size=38, color=VIOLET)
+        self.centered_text(58, "Curve", size=38, color=VIOLET)
+
+        # Render and place the figure
+        fig_path, fig_pw, fig_ph = self._render_dose_response_figure()
+        fig_margin = 25
+        fig_w = WIDTH - fig_margin * 2
+        fig_aspect = fig_ph / fig_pw
+        fig_h = fig_w * fig_aspect
+        fig_y = 80
+        self.image(fig_path, fig_margin, fig_y, fig_w)
+
+        # Annotations below figure
+        ann_y = fig_y + fig_h + 8
+        self.centered_text(
+            ann_y,
+            "ATT(d): total impact at each dose level",
+            size=16, bold=True, color=NAVY,
+        )
+        self.centered_text(
+            ann_y + 20,
+            "Confidence bands from influence functions or bootstrap",
+            size=14, bold=False, color=GRAY,
+        )
+
+        self.add_footer()
+
+    # ── Slide 6: Two Questions, One Estimator ─────────────────────────
+
+    def slide_two_questions(self):
+        """Slide 6: ATT(d) vs ACRT(d) side-by-side panels."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(25, "Two Questions", size=38, color=VIOLET)
+        self.centered_text(58, "One Estimator", size=38, color=VIOLET)
+
+        # Two side-by-side panels — compact to fill without dead space
+        margin = 25
+        gap = 12
+        panel_w = (WIDTH - margin * 2 - gap) / 2
+        panel_h = 115
+        panel_y = 95
+
+        panels = [
+            {
+                "x": margin,
+                "border_color": VIOLET,
+                "title": "ATT(d)",
+                "subtitle": "Level Effect",
+                "question": "What is the total impact\nat dose d?",
+                "example": "A $500 subsidy reduces\nemissions by 12 tons",
+            },
+            {
+                "x": margin + panel_w + gap,
+                "border_color": MID_BLUE,
+                "title": "ACRT(d)",
+                "subtitle": "Marginal Effect",
+                "question": "What is the return to one\nmore unit of dose?",
+                "example": "Each additional $100 reduces\nemissions by 1.8 tons",
+            },
+        ]
+
+        for panel in panels:
+            px = panel["x"]
+
+            # Panel box
+            self.set_fill_color(*WHITE)
+            self.set_draw_color(*panel["border_color"])
+            self.set_line_width(1.2)
+            self.rect(px, panel_y, panel_w, panel_h, "DF")
+
+            # Title
+            self.set_xy(px, panel_y + 8)
+            self.set_font("Helvetica", "B", 26)
+            self.set_text_color(*panel["border_color"])
+            self.cell(panel_w, 14, panel["title"], align="C")
+
+            # Subtitle
+            self.set_xy(px, panel_y + 30)
+            self.set_font("Helvetica", "B", 16)
+            self.set_text_color(*NAVY)
+            self.cell(panel_w, 10, panel["subtitle"], align="C")
+
+            # Horizontal rule
+            rule_y = panel_y + 46
+            self.set_draw_color(*panel["border_color"])
+            self.set_line_width(0.4)
+            self.line(px + 15, rule_y, px + panel_w - 15, rule_y)
+
+            # Question
+            self.set_xy(px + 8, panel_y + 52)
+            self.set_font("Helvetica", "I", 14)
+            self.set_text_color(*GRAY)
+            self.multi_cell(panel_w - 16, 13, panel["question"], align="C")
+
+            # Example
+            self.set_xy(px + 8, panel_y + 82)
+            self.set_font("Helvetica", "", 13)
+            self.set_text_color(*NAVY)
+            self.multi_cell(panel_w - 16, 13, panel["example"], align="C")
+
+        # Callout below panels
+        callout_y = panel_y + panel_h + 15
+        callout_margin = 40
+        callout_w = WIDTH - callout_margin * 2
+        self.set_fill_color(*VIOLET_TINT)
+        self.set_draw_color(*VIOLET)
+        self.set_line_width(0.8)
+        self.rect(callout_margin, callout_y, callout_w, 26, "DF")
+        self.set_xy(callout_margin, callout_y + 6)
+        self.set_font("Helvetica", "B", 15)
+        self.set_text_color(*VIOLET)
+        self.cell(
+            callout_w, 12,
+            "Both are functions of d -- not just single numbers.",
+            align="C",
+        )
+
+        # Annotation
+        self.centered_text(
+            callout_y + 34,
+            "Plus global summaries: overall ATT and overall ACRT",
+            size=14, bold=False, color=GRAY,
+        )
+
+        self.add_footer()
+
+    # ── Slide 7: Assumptions ─────────────────────────────────────────
+
+    def slide_assumptions(self):
+        """Slide 7: PT vs SPT — what you need to believe."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(25, "What You Need", size=38, color=VIOLET)
+        self.centered_text(58, "to Believe", size=38, color=VIOLET)
+
+        # Two assumption rows — PT (standard) and SPT (strong)
+        margin = 28
+        row_w = WIDTH - margin * 2
+        row_h = 68
+        row_gap = 10
+        row_y = 95
+
+        rows = [
+            {
+                "badge": "Standard PT",
+                "badge_color": MID_BLUE,
+                "headline": "Parallel trends in untreated outcomes",
+                "identifies": "ATT(d|d) level effects within each dose group",
+                "meaning": "Counterfactual trends are the same across\n"
+                           "all dose groups and the untreated.",
+            },
+            {
+                "badge": "Strong PT",
+                "badge_color": VIOLET,
+                "headline": "No selection into dose based on effects",
+                "identifies": "ATT(d) + ACRT(d) dose-response curves",
+                "meaning": "Units don't choose their dose based on\n"
+                           "how much they would benefit from it.",
+            },
+        ]
+
+        for i, row in enumerate(rows):
+            y = row_y + i * (row_h + row_gap)
+
+            # Row box
+            self.set_fill_color(*WHITE)
+            self.set_draw_color(*row["badge_color"])
+            self.set_line_width(1.0)
+            self.rect(margin, y, row_w, row_h, "DF")
+
+            # Badge overlapping top edge
+            badge_w = 80
+            badge_h = 18
+            badge_x = margin + 8
+            badge_y = y - badge_h / 2
+            self.set_fill_color(*row["badge_color"])
+            self.rect(badge_x, badge_y, badge_w, badge_h, "F")
+            self.set_xy(badge_x, badge_y + 3)
+            self.set_font("Helvetica", "B", 11)
+            self.set_text_color(*WHITE)
+            self.cell(badge_w, 12, row["badge"], align="C")
+
+            # Headline
+            self.set_xy(margin + 12, y + 12)
+            self.set_font("Helvetica", "B", 18)
+            self.set_text_color(*NAVY)
+            self.cell(row_w - 24, 10, row["headline"])
+
+            # Identifies label
+            self.set_xy(margin + 12, y + 28)
+            self.set_font("Helvetica", "B", 15)
+            self.set_text_color(*row["badge_color"])
+            self.cell(row_w - 24, 10,
+                      "Identifies:  " + row["identifies"])
+
+            # Meaning
+            self.set_xy(margin + 12, y + 43)
+            self.set_font("Helvetica", "", 14)
+            self.set_text_color(*GRAY)
+            self.multi_cell(row_w - 24, 11, row["meaning"])
+
+        # Key insight callout
+        callout_y = row_y + 2 * (row_h + row_gap) + 5
+        callout_margin = 32
+        callout_w = WIDTH - callout_margin * 2
+        self.set_fill_color(*VIOLET_TINT)
+        self.set_draw_color(*VIOLET)
+        self.set_line_width(0.8)
+        self.rect(callout_margin, callout_y, callout_w, 34, "DF")
+        self.set_xy(callout_margin + 8, callout_y + 4)
+        self.set_font("Helvetica", "", 14)
+        self.set_text_color(*VIOLET)
+        self.multi_cell(
+            callout_w - 16, 12,
+            "Note: Under standard PT, the slope of the dose-response\n"
+            "curve does NOT identify the causal marginal effect.",
+            align="C",
+        )
+
+        self.add_footer()
+
+    # ── Slide 8: Code Example ─────────────────────────────────────────
+
+    def slide_code(self):
+        """Slide 8: Drop-in API code example."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(30, "Drop-in", size=36)
+        self.centered_text(60, "API", size=36, color=VIOLET)
+
+        margin = 30
+        code_y = 95
+        code_lines = [
+            ("from diff_diff import ContinuousDiD", 1.0),
+            ("", 0.5),
+            ("est = ContinuousDiD(seed=42)", 1.0),
+            ("results = est.fit(", 1.0),
+            ("    data,", 1.0),
+            ("    outcome='outcome',", 1.0),
+            ("    unit='unit',", 1.0),
+            ("    time='period',", 1.0),
+            ("    first_treat='first_treat',", 1.0),
+            ("    dose='dose',", 1.0),
+            ("    aggregate='dose',", 1.0),
+            (")", 1.0),
+            ("", 0.5),
+            ("results.overall_att    # level effect", 1.0),
+            ("results.overall_acrt   # marginal effect", 1.0),
+        ]
+        line_height = 11
+        total_lines = sum(h for _, h in code_lines)
+        code_height = total_lines * line_height + 20
+
+        self.set_fill_color(*DARK_SLATE)
+        self.rect(margin, code_y, WIDTH - margin * 2, code_height, "F")
+
+        self.set_font("Courier", "", 13)
+        self.set_text_color(*WHITE)
+        cumulative_y = 0.0
+        for line_text, height_mult in code_lines:
+            self.set_xy(margin + 15, code_y + 10 + cumulative_y)
+            self.cell(0, 10, line_text)
+            cumulative_y += line_height * height_mult
+
+        subtitle_y = code_y + code_height + 12
+        self.centered_text(
+            subtitle_y,
+            "Same fit() API as every other diff-diff estimator.",
+            size=15, bold=False, color=GRAY,
+        )
+        self.centered_text(
+            subtitle_y + 17,
+            "Full walkthrough in Tutorial 14: Continuous DiD",
+            size=15, bold=False, color=GRAY,
+        )
+
+        self.add_footer()
+
+    # ── Slide 9: Use Cases ────────────────────────────────────────────
+
+    def slide_use_cases(self):
+        """Slide 9: Where Dose Matters — 2x2 grid of use-case cards."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(25, "Where Dose", size=38, color=VIOLET)
+        self.centered_text(58, "Matters", size=38, color=VIOLET)
+
+        margin = 28
+        gap = 10
+        card_w = (WIDTH - margin * 2 - gap) / 2
+        card_h = 68
+        grid_y = 95
+
+        cards = [
+            {
+                "title": "Job Training",
+                "desc": "Training hours as dose. How do\nearnings respond to each hour?",
+            },
+            {
+                "title": "Minimum Wage",
+                "desc": "Different increases across states.\nEmployment effect per dollar?",
+            },
+            {
+                "title": "Subsidies",
+                "desc": "Varying grant amounts. What is the\nmarginal return to spending?",
+            },
+            {
+                "title": "Pollution Exposure",
+                "desc": "Distance from source as dose.\nHow does health vary with proximity?",
+            },
+        ]
+
+        for i, card in enumerate(cards):
+            col = i % 2
+            row = i // 2
+            x = margin + col * (card_w + gap)
+            y = grid_y + row * (card_h + gap)
+
+            # Card box
+            self.set_fill_color(*WHITE)
+            self.set_draw_color(*VIOLET)
+            self.set_line_width(0.8)
+            self.rect(x, y, card_w, card_h, "DF")
+
+            # Card title
+            self.set_xy(x + 10, y + 8)
+            self.set_font("Helvetica", "B", 18)
+            self.set_text_color(*VIOLET)
+            self.cell(card_w - 20, 12, card["title"])
+
+            # Card description
+            self.set_xy(x + 10, y + 24)
+            self.set_font("Helvetica", "", 14)
+            self.set_text_color(*NAVY)
+            self.multi_cell(card_w - 20, 12, card["desc"], align="L")
+
+        # Subtitle below cards
+        cards_bottom = grid_y + 2 * (card_h + gap)
+        self.centered_text(
+            cards_bottom + 6,
+            "Any setting where treatment intensity varies across units.",
+            size=15, bold=False, color=GRAY,
+        )
+
+        self.add_footer()
+
+    # ── Slide 10: Full Toolkit ────────────────────────────────────────
+
+    def slide_full_toolkit(self):
+        """Slide 10: Every Method You Need — 6x2 grid (11 methods, last centered)."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(20, "Every Method", size=36)
+        self.centered_text(50, "You Need", size=36, color=MID_BLUE)
+
+        margin = 25
+        box_width = (WIDTH - margin * 3) / 2
+        box_height = 34
+        gap_y = 3
+        y_start = 80
+
+        methods = [
+            ("Basic DiD / TWFE", "Classic 2x2 and panel", False),
+            ("Callaway-Sant'Anna", "Staggered adoption (2021)", False),
+            ("Sun-Abraham", "Interaction-weighted (2021)", False),
+            ("Imputation DiD", "Borusyak et al. (2024)", False),
+            ("Two-Stage DiD", "Gardner (2022)", False),
+            ("Stacked DiD", "Wing et al. (2024)", False),
+            ("Continuous DiD", "Callaway et al. (2024)", True),
+            ("Synthetic DiD", "Arkhangelsky et al. (2021)", False),
+            ("Triple Difference", "DDD with proper covariates", False),
+            ("Honest DiD", "Rambachan-Roth sensitivity", False),
+            ("Bacon Decomposition", "TWFE diagnostic weights", False),
+        ]
+
+        for i, (title, desc, is_new) in enumerate(methods):
+            if i < 10:
+                col = i % 2
+                row = i // 2
+                x = margin + col * (box_width + margin)
+            else:
+                row = 5
+                x = (WIDTH - box_width) / 2
+
+            y = y_start + row * (box_height + gap_y)
+
+            self.set_fill_color(*WHITE)
+            if is_new:
+                self.set_draw_color(*VIOLET)
+                self.set_line_width(1.2)
+            else:
+                self.set_draw_color(*MID_BLUE)
+                self.set_line_width(0.8)
+            self.rect(x, y, box_width, box_height, "DF")
+
+            # Title
+            self.set_xy(x + 5, y + 3)
+            self.set_font("Helvetica", "B", 14)
+            self.set_text_color(*VIOLET if is_new else MID_BLUE)
+            display_title = title + "  [NEW]" if is_new else title
+            self.cell(box_width - 10, 10, display_title, align="C")
+
+            # Description
+            self.set_xy(x + 5, y + 19)
+            self.set_font("Helvetica", "", 11)
+            self.set_text_color(*GRAY)
+            self.cell(box_width - 10, 10, desc, align="C")
+
+        # Subtitle below grid
+        grid_bottom = y_start + 6 * (box_height + gap_y)
+        self.centered_text(
+            grid_bottom + 2,
+            "The most complete DiD toolkit in any language.",
+            size=15, bold=False, color=GRAY,
+        )
+        self.add_footer()
+
+    # ── Slide 11: CTA ─────────────────────────────────────────────────
+
+    def slide_cta(self):
+        """Slide 11: Upgrade to v2.6."""
+        self.add_page()
+        self.light_gradient_background()
+
+        self.centered_text(45, "Upgrade to", size=38)
+        self.centered_text(78, "v2.6", size=38, color=VIOLET)
+
+        box_width = 210
+        box_x = (WIDTH - box_width) / 2
+        box_y = 125
+        box_h = 36
+        self.set_fill_color(*MID_BLUE)
+        self.rect(box_x, box_y, box_width, box_h, "F")
+
+        self.set_xy(box_x, box_y + 10)
+        self.set_font("Courier", "B", 15)
+        self.set_text_color(*WHITE)
+        self.cell(box_width, 14, "$ pip install --upgrade diff-diff", align="C")
+
+        self.centered_text(200, "github.com/igerber/diff-diff", size=20,
+                           color=MID_BLUE)
+
+        self.centered_text(
+            232, "Full documentation & 14 tutorials included",
+            size=16, bold=False, color=GRAY,
+        )
+        self.centered_text(
+            252, "MIT Licensed  |  Open Source",
+            size=16, bold=False, color=GRAY,
+        )
+
+        self.draw_split_logo(278, size=28)
+
+        self.centered_text(
+            298, "Difference-in-Differences for Python",
+            size=14, bold=False, color=GRAY,
+        )
+
+
+def main():
+    pdf = CarouselV26PDF()
+
+    pdf.slide_hook()
+    pdf.slide_problem()
+    pdf.slide_solution()
+    pdf.slide_math()
+    pdf.slide_dose_response()
+    pdf.slide_two_questions()
+    pdf.slide_assumptions()
+    pdf.slide_code()
+    pdf.slide_use_cases()
+    pdf.slide_full_toolkit()
+    pdf.slide_cta()
+
+    output_path = Path(__file__).parent / "diff-diff-v26-carousel.pdf"
+    pdf.output(str(output_path))
+    print(f"PDF saved to: {output_path}")
+
+    pdf.cleanup()
+
+
+if __name__ == "__main__":
+    main()