Make dark theme

lib/main.dart

@@ -37,14 +37,64 @@ void main() async {
 class JournalerApp extends StatelessWidget {
   const JournalerApp({super.key});
 
+  // Define the light theme
+  static final ThemeData lightTheme = ThemeData(
+    brightness: Brightness.light,
+    primarySwatch: Colors.blue, // Or use ColorScheme.fromSeed(seedColor: Colors.blue)
+    visualDensity: VisualDensity.adaptivePlatformDensity,
+    scaffoldBackgroundColor: Colors.grey[100], // Slightly off-white
+    appBarTheme: const AppBarTheme(
+      backgroundColor: Colors.blue,
+      foregroundColor: Colors.white, // Title and icons
+    ),
+    inputDecorationTheme: InputDecorationTheme(
+      border: const OutlineInputBorder(),
+      focusedBorder: OutlineInputBorder(
+        borderSide: BorderSide(color: Colors.blue.shade600, width: 2.0),
+      ),
+      labelStyle: TextStyle(color: Colors.grey[700]),
+    ),
+    // Add other theme properties like textTheme if needed
+  );
+
+  // Define the dark theme
+  static final ThemeData darkTheme = ThemeData(
+    brightness: Brightness.dark,
+    primarySwatch: Colors.blue, // Keep blue, or choose a different shade
+    // Or use ColorScheme.fromSeed(seedColor: Colors.blue, brightness: Brightness.dark)
+    visualDensity: VisualDensity.adaptivePlatformDensity,
+    scaffoldBackgroundColor: Colors.grey[900], // Dark background
+    appBarTheme: AppBarTheme(
+      backgroundColor: Colors.grey[850], // Darker app bar
+      foregroundColor: Colors.white, // Title and icons
+    ),
+    inputDecorationTheme: InputDecorationTheme(
+      border: const OutlineInputBorder(
+        borderSide: BorderSide(color: Colors.grey), // Lighter border for dark theme
+      ),
+      focusedBorder: OutlineInputBorder(
+        borderSide: BorderSide(color: Colors.blue.shade300, width: 2.0),
+      ),
+      labelStyle: TextStyle(color: Colors.grey[400]), // Lighter label for dark theme
+      // Ensure content padding is applied if needed, or use default
+      // contentPadding: const EdgeInsets.all(8.0), // This was in TextField, maybe move to theme?
+    ),
+    // Ensure text field text color is readable
+    textTheme: const TextTheme(
+      bodyMedium: TextStyle(color: Colors.white), // Default text style
+      // Define other text styles as needed
+    ),
+    // Define icon theme for app bar if needed, though foregroundColor often handles it
+    // iconTheme: const IconThemeData(color: Colors.white),
+  );
+
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
       title: 'Journaler',
-      theme: ThemeData(
-        primarySwatch: Colors.blue,
-        visualDensity: VisualDensity.adaptivePlatformDensity,
-      ),
+      theme: lightTheme, // Use the light theme definition
+      darkTheme: darkTheme, // Use the dark theme definition
+      themeMode: ThemeMode.system, // Automatically switch based on system settings
       home: const MainPage(),
       debugShowCheckedModeBanner: false,
     );
@@ -275,8 +325,8 @@ class _MainPageState extends State<MainPage> with WindowListener {
                       readOnly: true, // Make it non-editable
                       decoration: const InputDecoration(
                         labelText: 'Previous Entry',
-                        border: OutlineInputBorder(),
-                        contentPadding: EdgeInsets.all(8.0),
+                        // border: OutlineInputBorder(), // Handled by theme
+                        // contentPadding: EdgeInsets.all(8.0), // Handled by theme or default
                       ),
                     ),
                   ),
@@ -290,8 +340,8 @@ class _MainPageState extends State<MainPage> with WindowListener {
                       autofocus: true, // Focus here when window appears
                       decoration: const InputDecoration(
                         labelText: 'Current Entry (What\'s on your mind?)',
-                        border: OutlineInputBorder(),
-                        contentPadding: EdgeInsets.all(8.0),
+                        // border: OutlineInputBorder(), // Handled by theme
+                        // contentPadding: EdgeInsets.all(8.0), // Handled by theme or default
                       ),
                       onChanged: (text) {
                         // Optional: Add auto-save logic here if desired
@@ -311,8 +361,8 @@ class _MainPageState extends State<MainPage> with WindowListener {
                 expands: true,
                 decoration: const InputDecoration(
                   labelText: 'Todo List',
-                  border: OutlineInputBorder(),
-                  contentPadding: EdgeInsets.all(8.0),
+                  // border: OutlineInputBorder(), // Handled by theme
+                  // contentPadding: EdgeInsets.all(8.0), // Handled by theme or default
                 ),
                 onChanged: (text) {
                   // Optional: Auto-save Todo list changes