fix: ER diagram — darker rows (#111d30/#152238), white text for high contrast

frontend/js/mermaid-viewer.js

@@ -137,17 +137,19 @@ var DARK_THEME = {
   classText: '#c8daf0',
   // State diagram
   labelColor: '#c8daf0',
-  // ER diagram — alternating row colors for readability
-  fillType0: '#1a2d47',
-  fillType1: '#1e3a55',
-  fillType2: '#223350',
-  fillType3: '#1a2a40',
-  fillType4: '#1e3350',
-  fillType5: '#223a58',
-  fillType6: '#1a2d47',
-  fillType7: '#1e3a55',
+  // ER diagram — dark alternating rows for readability
+  fillType0: '#111d30',
+  fillType1: '#152238',
+  fillType2: '#111d30',
+  fillType3: '#152238',
+  fillType4: '#111d30',
+  fillType5: '#152238',
+  fillType6: '#111d30',
+  fillType7: '#152238',
   entityBorder: '#4a7ab5',
-  attributeEvenColor: '#e0e8f0',
+  entityBackground: '#0d1520',
+  attributeEvenColor: '#ffffff',
+  attributeOddColor: '#c8daf0',
   // Timeline — section colors
   cScale0: '#1e3a5f',
   cScale1: '#2a5a8a',