diff --git a/CHANGELOG.md b/CHANGELOG.md
index ee39582..dc11c01 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -61,3 +61,6 @@ Format: [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Labeled container updates (rectangle, ellipse, diamond, arrow) now use convertToExcalidrawElements with ID transplant for correct text layout instead of in-place text patch that caused clipping
 - Standalone text element updates now write label.text into text/originalText fields so Excalidraw renders the new value
 - convertTextToLabel now maps text→label for arrows and empty strings (previously skipped falsy text)
+
+### Changed
+- Default theme set to dark
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 0a78e67..75d4769 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -1298,7 +1298,7 @@ function App(): JSX.Element {
           initialData={{
             elements: [],
             appState: {
-              theme: 'light',
+              theme: 'dark',
               viewBackgroundColor: '#ffffff'
             }
           }}