diff --git a/vizro-core/changelog.d/20240405_135655_huong_li_nguyen_change_theme_default.md b/vizro-core/changelog.d/20240405_135655_huong_li_nguyen_change_theme_default.md
new file mode 100644
index 000000000..f1186c8e9
--- /dev/null
+++ b/vizro-core/changelog.d/20240405_135655_huong_li_nguyen_change_theme_default.md
@@ -0,0 +1,47 @@
+<!--
+A new scriv changelog fragment.
+
+Uncomment the section that is right (remove the HTML comment wrapper).
+-->
+
+<!--
+### Highlights ✨
+
+- A bullet item for the Highlights ✨ category with a link to the relevant PR at the end of your entry, e.g. Enable feature XXX ([#1](https://github.com/mckinsey/vizro/pull/1))
+
+-->
+<!--
+### Removed
+
+- A bullet item for the Removed category with a link to the relevant PR at the end of your entry, e.g. Enable feature XXX ([#1](https://github.com/mckinsey/vizro/pull/1))
+
+-->
+<!--
+### Added
+
+- A bullet item for the Added category with a link to the relevant PR at the end of your entry, e.g. Enable feature XXX ([#1](https://github.com/mckinsey/vizro/pull/1))
+
+-->
+<!--
+### Changed
+
+- A bullet item for the Changed category with a link to the relevant PR at the end of your entry, e.g. Enable feature XXX ([#1](https://github.com/mckinsey/vizro/pull/1))
+
+-->
+<!--
+### Deprecated
+
+- A bullet item for the Deprecated category with a link to the relevant PR at the end of your entry, e.g. Enable feature XXX ([#1](https://github.com/mckinsey/vizro/pull/1))
+
+-->
+
+### Fixed
+
+- Turn on `autocolorscale` for color palettes to be assigned correctly in Plotly charts. ([#407](https://github.com/mckinsey/vizro/pull/407))
+
+<!--
+### Security
+
+- A bullet item for the Security category with a link to the relevant PR at the end of your entry, e.g. Enable feature XXX ([#1](https://github.com/mckinsey/vizro/pull/1))
+
+-->
diff --git a/vizro-core/examples/_dev/app.py b/vizro-core/examples/_dev/app.py
index 716e6f5bb..50dff9811 100644
--- a/vizro-core/examples/_dev/app.py
+++ b/vizro-core/examples/_dev/app.py
@@ -16,7 +16,7 @@
 
 
 @capture("graph")
-def variable_map(data_frame: pd.DataFrame = None, color: Optional[str] = None, title: Optional[str]=None):
+def variable_map(data_frame: pd.DataFrame = None, color: Optional[str] = None, title: Optional[str] = None):
     """Custom choropleth figure that needs post update calls."""
     fig = px.choropleth(
         data_frame,