diff --git a/moal/cli.py b/moal/cli.py
index 1da7d9e..f147e24 100644
--- a/moal/cli.py
+++ b/moal/cli.py
@@ -258,6 +258,9 @@ def simulate(config: Path, output_dir: Path | None, verbose: bool) -> None:
         html_path = out_dir / "dashboard_animation.html"
         dashboard.save_html(html_path)
 
+        html_cdn_path = out_dir / "dashboard_animation_cdn.html"
+        dashboard.save_html(html_cdn_path, use_cdn=True)
+
         gif_path = out_dir / "dashboard_animation.gif"
         dashboard.save_gif(gif_path)
         dashboard.close()
diff --git a/moal/dashboard.py b/moal/dashboard.py
index 27bd40c..b4aba92 100644
--- a/moal/dashboard.py
+++ b/moal/dashboard.py
@@ -487,7 +487,7 @@ def save_gif(
         except Exception as exc:
             logger.warning("Could not save dashboard GIF: %s", exc)
 
-    def save_html(self, path: str | Path) -> None:
+    def save_html(self, path: str | Path, *, use_cdn: bool = False) -> None:
         """Export the animated figure as a standalone HTML file.
 
         The exported file embeds an iteration slider and play/pause buttons so
@@ -498,12 +498,17 @@ def save_html(self, path: str | Path) -> None:
         ----------
         path : str or Path
             Destination file path (should end in ``.html``).
+        use_cdn : bool, optional
+            When ``True``, the Plotly JS bundle is loaded from the Plotly CDN
+            instead of being embedded in the file.  This reduces the file size
+            from ~3 MB to a few KB but requires an internet connection to view.
+            Default is ``False`` (fully self-contained file).
         """
         animated_fig = self._build_animated_figure()
         animated_fig.update_layout(width=self._export_width, height=self._export_height)
         animated_fig.write_html(
             str(path),
-            include_plotlyjs=True,
+            include_plotlyjs="cdn" if use_cdn else True,
             post_script=_PLAY_PAUSE_SCRIPT,
             auto_play=False,
         )
@@ -1151,10 +1156,10 @@ def _build_animated_figure(self) -> go.Figure:
                 "args": [
                     [str(i + 1)],
                     {
-                        "frame": {"duration": 350, "redraw": False},
+                        "frame": {"duration": 700, "redraw": False},
                         "mode": "immediate",
                         "transition": {
-                            "duration": 220,
+                            "duration": 300,
                             "easing": _EASING,
                             "ordering": "layout first",
                         },
diff --git a/moal/preprocessing.py b/moal/preprocessing.py
index da0f89f..364f2f2 100644
--- a/moal/preprocessing.py
+++ b/moal/preprocessing.py
@@ -58,7 +58,7 @@ def canonicalize(self, smiles: str) -> str | None:
         if mol is None or mol.GetNumAtoms() == 0:
             logger.warning("SMILES reduced to empty molecule after salt stripping: %s", smiles)
             return None
-        return Chem.MolToSmiles(mol, isomericSmiles=True)
+        return str(Chem.MolToSmiles(mol, isomericSmiles=True))
 
     def process_batch(self, smiles_list: list[str]) -> tuple[list[str], list[str]]:
         """Canonicalize a batch of SMILES strings.
diff --git a/tests/test_dashboard.py b/tests/test_dashboard.py
index 3f2324f..12467b0 100644
--- a/tests/test_dashboard.py
+++ b/tests/test_dashboard.py
@@ -554,6 +554,44 @@ def test_html_disables_plotly_builtin_autoplay(self, tmp_path):
         assert re.search(r"Plotly\.animate\('[^']+', null\);", content) is None
         assert "redraw: false" in content
 
+    def test_save_html_cdn_omits_embedded_plotlyjs(self, tmp_path):
+        """save_html(use_cdn=True) must load Plotly from CDN instead of embedding it."""
+        db = LiveDashboard(n_iterations=2, n_compounds=20)
+        records = _make_records(4)
+        for _ in range(2):
+            db.update(records, activity_threshold=7.0, iter_drc_cost=5.0, iter_ps_cost=1.0)
+
+        cdn_path = tmp_path / "dashboard_cdn.html"
+        embedded_path = tmp_path / "dashboard_embedded.html"
+        db.save_html(cdn_path, use_cdn=True)
+        db.save_html(embedded_path, use_cdn=False)
+        db.close()
+
+        cdn_content = cdn_path.read_text()
+
+        # CDN version must reference the Plotly CDN URL
+        assert "cdn.plot.ly" in cdn_content
+        # CDN version must be substantially smaller (no embedded JS bundle)
+        assert cdn_path.stat().st_size < embedded_path.stat().st_size
+
+    def test_slider_and_playback_use_same_frame_duration(self, tmp_path):
+        """Slider step args and the injected play script must use the same frame/transition durations."""
+        db = LiveDashboard(n_iterations=2, n_compounds=20)
+        records = _make_records(4)
+        for _ in range(2):
+            db.update(records, activity_threshold=7.0, iter_drc_cost=5.0, iter_ps_cost=1.0)
+
+        html_path = tmp_path / "dashboard.html"
+        db.save_html(html_path)
+        db.close()
+
+        content = html_path.read_text()
+        # Slider step JSON uses compact form; injected play script uses spaced form
+        assert '"duration":700' in content  # slider step frame duration
+        assert "duration: 700" in content  # injected JS play animation frame duration
+        assert '"duration":300' in content  # slider step transition duration
+        assert "duration: 300" in content  # injected JS play animation transition duration
+
     def test_animated_frames_include_per_iteration_axis_layout(self):
         """Animated HTML frames must carry per-iteration axis updates, not just trace data."""
         db = LiveDashboard(n_iterations=3, n_compounds=20)