refactor: improve layout responsiveness in overview screen and enhance theme separation with updated card and scaffold colors

Author: AsieduDevelopmentHub

dashboard/lib/screens/overview_screen.dart

@@ -623,11 +623,17 @@ class _StatsStrip extends StatelessWidget {
           ),
         ];
 
-        // Aim for 3 + 2 on typical widths.
-        final itemWidth = c.maxWidth >= 900 ? 210.0 : 180.0;
+        // Aim for 3 + 2 when space allows by computing width from constraints.
+        // This avoids the common 4 + 1 wrap that happens with a fixed tile width.
+        const gap = 14.0;
+        const minTileWidth = 180.0;
+        final canDoThree =
+            (c.maxWidth - (gap * 2)) / 3 >= minTileWidth; // 3 columns
+        final cols = canDoThree ? 3 : 2;
+        final itemWidth = (c.maxWidth - (gap * (cols - 1))) / cols;
         return Wrap(
-          spacing: 14,
-          runSpacing: 14,
+          spacing: gap,
+          runSpacing: gap,
           children: [
             for (final t in tiles) SizedBox(width: itemWidth, child: t),
           ],

dashboard/lib/theme/app_theme.dart

@@ -88,8 +88,10 @@ class AppTheme {
         displayColor: darkTextPrimary,
       ),
       cardTheme: CardThemeData(
-        color: darkSurface,
-        elevation: 1,
+        // Slightly brighter than scaffold for clearer separation.
+        color: darkSurfaceLight,
+        elevation: 2,
+        shadowColor: Colors.black.withValues(alpha: 0.35),
         margin: EdgeInsets.zero,
         shape: RoundedRectangleBorder(
           borderRadius: BorderRadius.circular(12),
@@ -123,7 +125,8 @@ class AppTheme {
     return ThemeData(
       useMaterial3: true,
       brightness: Brightness.light,
-      scaffoldBackgroundColor: lightBackground,
+      // Slightly darker than card surface for clear separation.
+      scaffoldBackgroundColor: const Color(0xFFF3F6FB),
       colorScheme: const ColorScheme.light(
         surface: lightSurface,
         primary: primary,
@@ -136,8 +139,8 @@ class AppTheme {
       ),
       cardTheme: CardThemeData(
         color: lightSurface,
-        elevation: 1,
-        shadowColor: Colors.black.withValues(alpha: 0.08),
+        elevation: 2,
+        shadowColor: Colors.black.withValues(alpha: 0.06),
         margin: EdgeInsets.zero,
         shape: RoundedRectangleBorder(
           borderRadius: BorderRadius.circular(12),