debug: v1.7.0 Features - Grid Layout, WiFi-only Sync, VPN Support

android/app/src/main/java/dev/dettmer/simplenotes/backup/BackupManager.kt

@@ -31,20 +31,24 @@ class BackupManager(private val context: Context) {
         private const val BACKUP_VERSION = 1
         private const val AUTO_BACKUP_DIR = "auto_backups"
         private const val AUTO_BACKUP_RETENTION_DAYS = 7
+        private const val MAGIC_BYTES_LENGTH = 4  // v1.7.0: For encryption check
     }
     
     private val storage = NotesStorage(context)
     private val gson: Gson = GsonBuilder().setPrettyPrinting().create()
+    private val encryptionManager = EncryptionManager()  // 🔐 v1.7.0
     
     /**
      * Erstellt Backup aller Notizen
      * 
      * @param uri Output-URI (via Storage Access Framework)
+     * @param password Optional password for encryption (null = unencrypted)
      * @return BackupResult mit Erfolg/Fehler Info
      */
-    suspend fun createBackup(uri: Uri): BackupResult = withContext(Dispatchers.IO) {
+    suspend fun createBackup(uri: Uri, password: String? = null): BackupResult = withContext(Dispatchers.IO) {
         return@withContext try {
-            Logger.d(TAG, "📦 Creating backup to: $uri")
+            val encryptedSuffix = if (password != null) " (encrypted)" else ""
+            Logger.d(TAG, "📦 Creating backup$encryptedSuffix to: $uri")
             
             val allNotes = storage.loadAllNotes()
             Logger.d(TAG, "   Found ${allNotes.size} notes to backup")
@@ -59,15 +63,22 @@ class BackupManager(private val context: Context) {
             
             val jsonString = gson.toJson(backupData)
             
+            // 🔐 v1.7.0: Encrypt if password is provided
+            val dataToWrite = if (password != null) {
+                encryptionManager.encrypt(jsonString.toByteArray(), password)
+            } else {
+                jsonString.toByteArray()
+            }
+            
             context.contentResolver.openOutputStream(uri)?.use { outputStream ->
-                outputStream.write(jsonString.toByteArray())
-                Logger.d(TAG, "✅ Backup created successfully")
+                outputStream.write(dataToWrite)
+                Logger.d(TAG, "✅ Backup created successfully$encryptedSuffix")
             }
             
             BackupResult(
                 success = true,
                 notesCount = allNotes.size,
-                message = "Backup erstellt: ${allNotes.size} Notizen"
+                message = "Backup erstellt: ${allNotes.size} Notizen$encryptedSuffix"
             )
             
         } catch (e: Exception) {
@@ -126,20 +137,42 @@ class BackupManager(private val context: Context) {
      * 
      * @param uri Backup-Datei URI
      * @param mode Wiederherstellungs-Modus (Merge/Replace/Overwrite)
+     * @param password Optional password if backup is encrypted
      * @return RestoreResult mit Details
      */
-    suspend fun restoreBackup(uri: Uri, mode: RestoreMode): RestoreResult = withContext(Dispatchers.IO) {
+    suspend fun restoreBackup(uri: Uri, mode: RestoreMode, password: String? = null): RestoreResult = withContext(Dispatchers.IO) {
         return@withContext try {
             Logger.d(TAG, "📥 Restoring backup from: $uri (mode: $mode)")
             
             // 1. Backup-Datei lesen
-            val jsonString = context.contentResolver.openInputStream(uri)?.use { inputStream ->
-                inputStream.bufferedReader().use { it.readText() }
+            val fileData = context.contentResolver.openInputStream(uri)?.use { inputStream ->
+                inputStream.readBytes()
             } ?: return@withContext RestoreResult(
                 success = false,
                 error = "Datei konnte nicht gelesen werden"
             )
             
+            // 🔐 v1.7.0: Check if encrypted and decrypt if needed
+            val jsonString = try {
+                if (encryptionManager.isEncrypted(fileData)) {
+                    if (password == null) {
+                        return@withContext RestoreResult(
+                            success = false,
+                            error = "Backup ist verschlüsselt. Bitte Passwort eingeben."
+                        )
+                    }
+                    val decrypted = encryptionManager.decrypt(fileData, password)
+                    String(decrypted)
+                } else {
+                    String(fileData)
+                }
+            } catch (e: EncryptionException) {
+                return@withContext RestoreResult(
+                    success = false,
+                    error = "Entschlüsselung fehlgeschlagen: ${e.message}"
+                )
+            }
+            
             // 2. Backup validieren & parsen
             val validationResult = validateBackup(jsonString)
             if (!validationResult.isValid) {
@@ -177,6 +210,22 @@ class BackupManager(private val context: Context) {
         }
     }
     
+    /**
+     * 🔐 v1.7.0: Check if backup file is encrypted
+     */
+    suspend fun isBackupEncrypted(uri: Uri): Boolean = withContext(Dispatchers.IO) {
+        return@withContext try {
+            context.contentResolver.openInputStream(uri)?.use { inputStream ->
+                val header = ByteArray(MAGIC_BYTES_LENGTH)
+                val bytesRead = inputStream.read(header)
+                bytesRead == MAGIC_BYTES_LENGTH && encryptionManager.isEncrypted(header)
+            } ?: false
+        } catch (e: Exception) {
+            Logger.e(TAG, "Failed to check encryption status", e)
+            false
+        }
+    }
+    
     /**
      * Validiert Backup-Datei
      */

android/app/src/main/java/dev/dettmer/simplenotes/backup/EncryptionManager.kt

@@ -0,0 +1,172 @@
+package dev.dettmer.simplenotes.backup
+
+import dev.dettmer.simplenotes.utils.Logger
+import java.nio.ByteBuffer
+import java.nio.charset.StandardCharsets
+import java.security.SecureRandom
+import javax.crypto.Cipher
+import javax.crypto.SecretKeyFactory
+import javax.crypto.spec.GCMParameterSpec
+import javax.crypto.spec.PBEKeySpec
+import javax.crypto.spec.SecretKeySpec
+
+/**
+ * 🔐 v1.7.0: Encryption Manager for Backup Files
+ * 
+ * Provides AES-256-GCM encryption for local backups with:
+ * - Password-based encryption (PBKDF2 key derivation)
+ * - Random salt + IV for each encryption
+ * - GCM authentication tag for integrity
+ * - Simple file format: [MAGIC][VERSION][SALT][IV][ENCRYPTED_DATA]
+ */
+class EncryptionManager {
+    
+    companion object {
+        private const val TAG = "EncryptionManager"
+        
+        // File format constants
+        private const val MAGIC = "SNE1"  // Simple Notes Encrypted v1
+        private const val VERSION: Byte = 1
+        private const val MAGIC_BYTES = 4
+        private const val VERSION_BYTES = 1
+        private const val SALT_LENGTH = 32  // 256 bits
+        private const val IV_LENGTH = 12    // 96 bits (recommended for GCM)
+        private const val HEADER_LENGTH = MAGIC_BYTES + VERSION_BYTES + SALT_LENGTH + IV_LENGTH  // 49 bytes
+        
+        // Encryption constants
+        private const val KEY_LENGTH = 256  // AES-256
+        private const val GCM_TAG_LENGTH = 128  // 128 bits
+        private const val PBKDF2_ITERATIONS = 100_000  // OWASP recommendation
+        
+        // Algorithm names
+        private const val KEY_DERIVATION_ALGORITHM = "PBKDF2WithHmacSHA256"
+        private const val ENCRYPTION_ALGORITHM = "AES/GCM/NoPadding"
+    }
+    
+    /**
+     * Encrypt data with password
+     * 
+     * @param data Plaintext data to encrypt
+     * @param password User password
+     * @return Encrypted byte array with header [MAGIC][VERSION][SALT][IV][CIPHERTEXT]
+     */
+    fun encrypt(data: ByteArray, password: String): ByteArray {
+        Logger.d(TAG, "🔐 Encrypting ${data.size} bytes...")
+        
+        // Generate random salt and IV
+        val salt = ByteArray(SALT_LENGTH)
+        val iv = ByteArray(IV_LENGTH)
+        SecureRandom().apply {
+            nextBytes(salt)
+            nextBytes(iv)
+        }
+        
+        // Derive encryption key from password
+        val key = deriveKey(password, salt)
+        
+        // Encrypt data
+        val cipher = Cipher.getInstance(ENCRYPTION_ALGORITHM)
+        val secretKey = SecretKeySpec(key, "AES")
+        val gcmSpec = GCMParameterSpec(GCM_TAG_LENGTH, iv)
+        cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmSpec)
+        val ciphertext = cipher.doFinal(data)
+        
+        // Build encrypted file: MAGIC + VERSION + SALT + IV + CIPHERTEXT
+        val result = ByteBuffer.allocate(HEADER_LENGTH + ciphertext.size).apply {
+            put(MAGIC.toByteArray(StandardCharsets.US_ASCII))
+            put(VERSION)
+            put(salt)
+            put(iv)
+            put(ciphertext)
+        }.array()
+        
+        Logger.d(TAG, "✅ Encryption successful: ${result.size} bytes (header: $HEADER_LENGTH, ciphertext: ${ciphertext.size})")
+        return result
+    }
+    
+    /**
+     * Decrypt data with password
+     * 
+     * @param encryptedData Encrypted byte array (with header)
+     * @param password User password
+     * @return Decrypted plaintext
+     * @throws EncryptionException if decryption fails (wrong password, corrupted data, etc.)
+     */
+    @Suppress("ThrowsCount") // Multiple validation steps require separate throws
+    fun decrypt(encryptedData: ByteArray, password: String): ByteArray {
+        Logger.d(TAG, "🔓 Decrypting ${encryptedData.size} bytes...")
+        
+        // Validate minimum size
+        if (encryptedData.size < HEADER_LENGTH) {
+            throw EncryptionException("File too small: ${encryptedData.size} bytes (expected at least $HEADER_LENGTH)")
+        }
+        
+        // Parse header
+        val buffer = ByteBuffer.wrap(encryptedData)
+        
+        // Verify magic bytes
+        val magic = ByteArray(MAGIC_BYTES)
+        buffer.get(magic)
+        val magicString = String(magic, StandardCharsets.US_ASCII)
+        if (magicString != MAGIC) {
+            throw EncryptionException("Invalid file format: expected '$MAGIC', got '$magicString'")
+        }
+        
+        // Check version
+        val version = buffer.get()
+        if (version != VERSION) {
+            throw EncryptionException("Unsupported version: $version (expected $VERSION)")
+        }
+        
+        // Extract salt and IV
+        val salt = ByteArray(SALT_LENGTH)
+        val iv = ByteArray(IV_LENGTH)
+        buffer.get(salt)
+        buffer.get(iv)
+        
+        // Extract ciphertext
+        val ciphertext = ByteArray(buffer.remaining())
+        buffer.get(ciphertext)
+        
+        // Derive key from password
+        val key = deriveKey(password, salt)
+        
+        // Decrypt
+        return try {
+            val cipher = Cipher.getInstance(ENCRYPTION_ALGORITHM)
+            val secretKey = SecretKeySpec(key, "AES")
+            val gcmSpec = GCMParameterSpec(GCM_TAG_LENGTH, iv)
+            cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmSpec)
+            val plaintext = cipher.doFinal(ciphertext)
+            
+            Logger.d(TAG, "✅ Decryption successful: ${plaintext.size} bytes")
+            plaintext
+        } catch (e: Exception) {
+            Logger.e(TAG, "Decryption failed", e)
+            throw EncryptionException("Decryption failed: ${e.message}. Wrong password?", e)
+        }
+    }
+    
+    /**
+     * Derive 256-bit encryption key from password using PBKDF2
+     */
+    private fun deriveKey(password: String, salt: ByteArray): ByteArray {
+        val spec = PBEKeySpec(password.toCharArray(), salt, PBKDF2_ITERATIONS, KEY_LENGTH)
+        val factory = SecretKeyFactory.getInstance(KEY_DERIVATION_ALGORITHM)
+        return factory.generateSecret(spec).encoded
+    }
+    
+    /**
+     * Check if data is encrypted (starts with magic bytes)
+     */
+    fun isEncrypted(data: ByteArray): Boolean {
+        if (data.size < MAGIC_BYTES) return false
+        val magic = data.sliceArray(0 until MAGIC_BYTES)
+        return String(magic, StandardCharsets.US_ASCII) == MAGIC
+    }
+}
+
+/**
+ * Exception thrown when encryption/decryption fails
+ */
+class EncryptionException(message: String, cause: Throwable? = null) : Exception(message, cause)

android/app/src/main/java/dev/dettmer/simplenotes/models/Note.kt

@@ -323,6 +323,34 @@ type: ${noteType.name.lowercase()}
     }
 }
 
+/**
+ * 🎨 v1.7.0: Note size classification for Staggered Grid Layout
+ */
+enum class NoteSize {
+    SMALL,  // Compact display (< 80 chars or ≤ 4 checklist items)
+    LARGE;  // Full-width display
+    
+    companion object {
+        const val SMALL_TEXT_THRESHOLD = 80  // Max characters for compact text note
+        const val SMALL_CHECKLIST_THRESHOLD = 4  // Max items for compact checklist
+    }
+}
+
+/**
+ * 🎨 v1.7.0: Determine note size for grid layout optimization
+ */
+fun Note.getSize(): NoteSize {
+    return when (noteType) {
+        NoteType.TEXT -> {
+            if (content.length < NoteSize.SMALL_TEXT_THRESHOLD) NoteSize.SMALL else NoteSize.LARGE
+        }
+        NoteType.CHECKLIST -> {
+            val itemCount = checklistItems?.size ?: 0
+            if (itemCount <= NoteSize.SMALL_CHECKLIST_THRESHOLD) NoteSize.SMALL else NoteSize.LARGE
+        }
+    }
+}
+
 // Extension für JSON-Escaping
 fun String.escapeJson(): String {
     return this

android/app/src/main/java/dev/dettmer/simplenotes/storage/NotesStorage.kt

@@ -123,6 +123,26 @@ class NotesStorage(private val context: Context) {
         saveDeletionTracker(DeletionTracker())
         Logger.d(TAG, "🗑️ Deletion tracker cleared")
     }
+    
+    /**
+     * 🔄 v1.7.0: Reset all sync statuses to PENDING when server changes
+     * This ensures notes are uploaded to the new server on next sync
+     */
+    fun resetAllSyncStatusToPending(): Int {
+        val notes = loadAllNotes()
+        var updatedCount = 0
+        
+        notes.forEach { note ->
+            if (note.syncStatus == dev.dettmer.simplenotes.models.SyncStatus.SYNCED) {
+                val updatedNote = note.copy(syncStatus = dev.dettmer.simplenotes.models.SyncStatus.PENDING)
+                saveNote(updatedNote)
+                updatedCount++
+            }
+        }
+        
+        Logger.d(TAG, "🔄 Reset sync status for $updatedCount notes to PENDING")
+        return updatedCount
+    }
 
     
     fun getNotesDir(): File = notesDir

android/app/src/main/java/dev/dettmer/simplenotes/sync/WebDavSyncService.kt

@@ -41,7 +41,7 @@ class WebDavSyncService(private val context: Context) {
     
     companion object {
         private const val TAG = "WebDavSyncService"
-        private const val SOCKET_TIMEOUT_MS = 2000
+        private const val SOCKET_TIMEOUT_MS = 1000  // 🆕 v1.7.0: Reduziert von 2s auf 1s
         private const val MAX_FILENAME_LENGTH = 200
         private const val ETAG_PREVIEW_LENGTH = 8
         private const val CONTENT_PREVIEW_LENGTH = 50
@@ -130,7 +130,14 @@ class WebDavSyncService(private val context: Context) {
                 return null
             }
             
-            // Nur wenn WiFi aktiv
+            // 🔒 v1.7.0: VPN-Detection - Skip WiFi binding when VPN is active
+            // When VPN is active, traffic should route through VPN, not directly via WiFi
+            if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_VPN)) {
+                Logger.d(TAG, "🔒 VPN detected - using default routing (traffic will go through VPN)")
+                return null
+            }
+            
+            // Nur wenn WiFi aktiv (und kein VPN)
             if (!capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
                 Logger.d(TAG, "⚠️ Not on WiFi, using default routing")
                 return null
@@ -556,6 +563,25 @@ class WebDavSyncService(private val context: Context) {
         }
     }
     
+    /**
+     * 🆕 v1.7.0: Prüft ob Gerät aktuell im WLAN ist
+     * Für schnellen Pre-Check VOR dem langsamen Socket-Check
+     * 
+     * @return true wenn WLAN verbunden, false sonst (mobil oder kein Netzwerk)
+     */
+    fun isOnWiFi(): Boolean {
+        return try {
+            val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) 
+                as? ConnectivityManager ?: return false
+            val network = connectivityManager.activeNetwork ?: return false
+            val capabilities = connectivityManager.getNetworkCapabilities(network) ?: return false
+            capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)
+        } catch (e: Exception) {
+            Logger.e(TAG, "Failed to check WiFi state", e)
+            false
+        }
+    }
+    
     suspend fun testConnection(): SyncResult = withContext(Dispatchers.IO) {
         return@withContext try {
             val sardine = getOrCreateSardine() ?: return@withContext SyncResult(

android/app/src/main/java/dev/dettmer/simplenotes/ui/editor/NoteEditorScreen.kt

@@ -83,6 +83,11 @@ fun NoteEditorScreen(
     var focusNewItemId by remember { mutableStateOf<String?>(null) }
     val scope = rememberCoroutineScope()
     
+    // Strings for toast messages (avoid LocalContextGetResourceValueCall lint)
+    val msgNoteIsEmpty = stringResource(R.string.note_is_empty)
+    val msgNoteSaved = stringResource(R.string.note_saved)
+    val msgNoteDeleted = stringResource(R.string.note_deleted)
+    
     // v1.5.0: Auto-keyboard support
     val keyboardController = LocalSoftwareKeyboardController.current
     val titleFocusRequester = remember { FocusRequester() }
@@ -111,9 +116,9 @@ fun NoteEditorScreen(
             when (event) {
                 is NoteEditorEvent.ShowToast -> {
                     val message = when (event.message) {
-                        ToastMessage.NOTE_IS_EMPTY -> context.getString(R.string.note_is_empty)
-                        ToastMessage.NOTE_SAVED -> context.getString(R.string.note_saved)
-                        ToastMessage.NOTE_DELETED -> context.getString(R.string.note_deleted)
+                        ToastMessage.NOTE_IS_EMPTY -> msgNoteIsEmpty
+                        ToastMessage.NOTE_SAVED -> msgNoteSaved
+                        ToastMessage.NOTE_DELETED -> msgNoteDeleted
                     }
                     context.showToast(message)
                 }

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/ComposeMainActivity.kt

@@ -183,6 +183,9 @@ class ComposeMainActivity : ComponentActivity() {
         // This ensures UI reflects current offline mode when returning from Settings
         viewModel.refreshOfflineModeState()
         
+        // 🎨 v1.7.0: Refresh display mode when returning from Settings
+        viewModel.refreshDisplayMode()
+        
         // Register BroadcastReceiver for Background-Sync
         @Suppress("DEPRECATION") // LocalBroadcastManager deprecated but functional
         LocalBroadcastManager.getInstance(this).registerReceiver(

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/MainScreen.kt

@@ -10,6 +10,7 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.lazy.staggeredgrid.rememberLazyStaggeredGridState
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Delete
@@ -50,6 +51,7 @@ import dev.dettmer.simplenotes.ui.main.components.DeleteConfirmationDialog
 import dev.dettmer.simplenotes.ui.main.components.EmptyState
 import dev.dettmer.simplenotes.ui.main.components.NoteTypeFAB
 import dev.dettmer.simplenotes.ui.main.components.NotesList
+import dev.dettmer.simplenotes.ui.main.components.NotesStaggeredGrid
 import dev.dettmer.simplenotes.ui.main.components.SyncStatusBanner
 import kotlinx.coroutines.launch
 
@@ -82,12 +84,17 @@ fun MainScreen(
     // 🌟 v1.6.0: Reactive offline mode state
     val isOfflineMode by viewModel.isOfflineMode.collectAsState()
     
+    // 🎨 v1.7.0: Display mode (list or grid)
+    val displayMode by viewModel.displayMode.collectAsState()
+    
     // Delete confirmation dialog state
     var showBatchDeleteDialog by remember { mutableStateOf(false) }
     
     val snackbarHostState = remember { SnackbarHostState() }
     val scope = rememberCoroutineScope()
     val listState = rememberLazyListState()
+    // 🎨 v1.7.0: gridState für Staggered Grid Layout
+    val gridState = rememberLazyStaggeredGridState()
     
     // Compute isSyncing once
     val isSyncing = syncState == SyncStateManager.SyncState.SYNCING
@@ -116,9 +123,14 @@ fun MainScreen(
     }
     
     // Phase 3: Scroll to top when new note created
+    // 🎨 v1.7.0: Unterstützt beide Display-Modi (list & grid)
     LaunchedEffect(scrollToTop) {
         if (scrollToTop) {
-            listState.animateScrollToItem(0)
+            if (displayMode == "grid") {
+                gridState.animateScrollToItem(0)
+            } else {
+                listState.animateScrollToItem(0)
+            }
             viewModel.resetScrollToTop()
         }
     }
@@ -177,22 +189,44 @@ fun MainScreen(
                     if (notes.isEmpty()) {
                         EmptyState(modifier = Modifier.weight(1f))
                     } else {
-                        NotesList(
-                            notes = notes,
-                            showSyncStatus = viewModel.isServerConfigured(),
-                            selectedNotes = selectedNotes,
-                            isSelectionMode = isSelectionMode,
-                            listState = listState,
-                            modifier = Modifier.weight(1f),
-                            onNoteClick = { note -> onOpenNote(note.id) },
-                            onNoteLongPress = { note -> 
-                                // Long-press starts selection mode
-                                viewModel.startSelectionMode(note.id)
-                            },
-                            onNoteSelectionToggle = { note ->
-                                viewModel.toggleNoteSelection(note.id)
-                            }
-                        )
+                        // 🎨 v1.7.0: Switch between List and Grid based on display mode
+                        if (displayMode == "grid") {
+                            NotesStaggeredGrid(
+                                notes = notes,
+                                gridState = gridState,
+                                showSyncStatus = viewModel.isServerConfigured(),
+                                selectedNoteIds = selectedNotes,
+                                isSelectionMode = isSelectionMode,
+                                modifier = Modifier.weight(1f),
+                                onNoteClick = { note ->
+                                    if (isSelectionMode) {
+                                        viewModel.toggleNoteSelection(note.id)
+                                    } else {
+                                        onOpenNote(note.id)
+                                    }
+                                },
+                                onNoteLongClick = { note ->
+                                    viewModel.startSelectionMode(note.id)
+                                }
+                            )
+                        } else {
+                            NotesList(
+                                notes = notes,
+                                showSyncStatus = viewModel.isServerConfigured(),
+                                selectedNotes = selectedNotes,
+                                isSelectionMode = isSelectionMode,
+                                listState = listState,
+                                modifier = Modifier.weight(1f),
+                                onNoteClick = { note -> onOpenNote(note.id) },
+                                onNoteLongPress = { note -> 
+                                    // Long-press starts selection mode
+                                    viewModel.startSelectionMode(note.id)
+                                },
+                                onNoteSelectionToggle = { note ->
+                                    viewModel.toggleNoteSelection(note.id)
+                                }
+                            )
+                        }
                     }
                 }
                 

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/MainViewModel.kt

@@ -11,7 +11,6 @@ import dev.dettmer.simplenotes.sync.SyncStateManager
 import dev.dettmer.simplenotes.sync.WebDavSyncService
 import dev.dettmer.simplenotes.utils.Constants
 import dev.dettmer.simplenotes.utils.Logger
-import dev.dettmer.simplenotes.utils.SyncConstants
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -83,6 +82,25 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
         Logger.d(TAG, "🔄 refreshOfflineModeState: offlineMode=$oldValue → $newValue")
     }
     
+    // ═══════════════════════════════════════════════════════════════════════
+    // 🎨 v1.7.0: Display Mode State
+    // ═══════════════════════════════════════════════════════════════════════
+    
+    private val _displayMode = MutableStateFlow(
+        prefs.getString(Constants.KEY_DISPLAY_MODE, Constants.DEFAULT_DISPLAY_MODE) ?: Constants.DEFAULT_DISPLAY_MODE
+    )
+    val displayMode: StateFlow<String> = _displayMode.asStateFlow()
+    
+    /**
+     * Refresh display mode from SharedPreferences
+     * Called when returning from Settings screen
+     */
+    fun refreshDisplayMode() {
+        val newValue = prefs.getString(Constants.KEY_DISPLAY_MODE, Constants.DEFAULT_DISPLAY_MODE) ?: Constants.DEFAULT_DISPLAY_MODE
+        _displayMode.value = newValue
+        Logger.d(TAG, "🔄 refreshDisplayMode: displayMode=${_displayMode.value} → $newValue")
+    }
+    
     // ═══════════════════════════════════════════════════════════════════════
     // Sync State (derived from SyncStateManager)
     // ═══════════════════════════════════════════════════════════════════════
@@ -490,7 +508,29 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
             return
         }
         
+        // 🆕 v1.7.0: WiFi-Only Check (sofort, kein Netzwerk-Wait)
+        val wifiOnlySync = prefs.getBoolean(Constants.KEY_WIFI_ONLY_SYNC, Constants.DEFAULT_WIFI_ONLY_SYNC)
+        if (wifiOnlySync) {
+            val syncService = WebDavSyncService(getApplication())
+            if (!syncService.isOnWiFi()) {
+                Logger.d(TAG, "⏭️ $source Sync blocked: WiFi-only mode, not on WiFi")
+                SyncStateManager.markError(getString(R.string.sync_wifi_only_hint))
+                return
+            }
+        }
+        
+        // 🆕 v1.7.0: Feedback wenn Sync bereits läuft
         if (!SyncStateManager.tryStartSync(source)) {
+            if (SyncStateManager.isSyncing) {
+                Logger.d(TAG, "⏭️ $source Sync blocked: Another sync in progress")
+                viewModelScope.launch {
+                    _showSnackbar.emit(SnackbarData(
+                        message = getString(R.string.sync_already_running),
+                        actionLabel = "",
+                        onAction = {}
+                    ))
+                }
+            }
             return
         }
         

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/components/NoteCard.kt

@@ -72,7 +72,7 @@ fun NoteCard(
     Card(
         modifier = modifier
             .fillMaxWidth()
-            .padding(horizontal = 16.dp, vertical = 4.dp)
+            // 🎨 v1.7.0: Externes Padding entfernt - Grid/Liste steuert Abstände
             .then(
                 if (isSelected) {
                     Modifier.border(

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/components/NoteCardCompact.kt

@@ -0,0 +1,246 @@
+package dev.dettmer.simplenotes.ui.main.components
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.scaleIn
+import androidx.compose.animation.scaleOut
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.outlined.List
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material.icons.filled.Warning
+import androidx.compose.material.icons.outlined.CloudDone
+import androidx.compose.material.icons.outlined.CloudOff
+import androidx.compose.material.icons.outlined.CloudSync
+import androidx.compose.material.icons.outlined.Description
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import dev.dettmer.simplenotes.R
+import dev.dettmer.simplenotes.models.Note
+import dev.dettmer.simplenotes.models.NoteType
+import dev.dettmer.simplenotes.models.SyncStatus
+import dev.dettmer.simplenotes.utils.toReadableTime
+
+/**
+ * 🎨 v1.7.0: Compact Note Card for Grid Layout
+ * 
+ * COMPACT DESIGN für kleine Notizen:
+ * - Reduzierter Padding (12dp statt 16dp)
+ * - Kleinere Icons (24dp statt 32dp)
+ * - Kompakte Typography (titleSmall)
+ * - Max 3 Zeilen Preview
+ * - Optimiert für Grid-Ansicht
+ */
+@Composable
+fun NoteCardCompact(
+    note: Note,
+    showSyncStatus: Boolean,
+    isSelected: Boolean = false,
+    isSelectionMode: Boolean = false,
+    modifier: Modifier = Modifier,
+    onClick: () -> Unit,
+    onLongClick: () -> Unit
+) {
+    val context = LocalContext.current
+    
+    Card(
+        modifier = modifier
+            .fillMaxWidth()
+            .then(
+                if (isSelected) {
+                    Modifier.border(
+                        width = 2.dp,
+                        color = MaterialTheme.colorScheme.primary,
+                        shape = RoundedCornerShape(12.dp)
+                    )
+                } else Modifier
+            )
+            .pointerInput(note.id, isSelectionMode) {
+                detectTapGestures(
+                    onTap = { onClick() },
+                    onLongPress = { onLongClick() }
+                )
+            },
+        shape = RoundedCornerShape(12.dp),
+        elevation = CardDefaults.cardElevation(defaultElevation = 0.dp),
+        colors = CardDefaults.cardColors(
+            containerColor = if (isSelected) {
+                MaterialTheme.colorScheme.primaryContainer.copy(alpha = 0.3f)
+            } else {
+                MaterialTheme.colorScheme.surfaceContainerHigh
+            }
+        )
+    ) {
+        Box {
+            Column(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(12.dp)
+            ) {
+                // Header row - COMPACT
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    // Type icon - SMALLER
+                    Box(
+                        modifier = Modifier
+                            .size(24.dp)
+                            .background(
+                                MaterialTheme.colorScheme.primaryContainer,
+                                CircleShape
+                            ),
+                        contentAlignment = Alignment.Center
+                    ) {
+                        Icon(
+                            imageVector = if (note.noteType == NoteType.TEXT) 
+                                Icons.Outlined.Description 
+                            else 
+                                Icons.AutoMirrored.Outlined.List,
+                            contentDescription = null,
+                            tint = MaterialTheme.colorScheme.onPrimaryContainer,
+                            modifier = Modifier.size(12.dp)
+                        )
+                    }
+                    
+                    Spacer(modifier = Modifier.width(8.dp))
+                    
+                    // Title - COMPACT Typography
+                    Text(
+                        text = note.title.ifEmpty { stringResource(R.string.untitled) },
+                        style = MaterialTheme.typography.titleSmall,
+                        color = MaterialTheme.colorScheme.onSurface,
+                        maxLines = 1,
+                        overflow = TextOverflow.Ellipsis,
+                        modifier = Modifier.weight(1f)
+                    )
+                }
+                
+                Spacer(modifier = Modifier.height(6.dp))
+                
+                // Preview - MAX 3 ZEILEN
+                Text(
+                    text = when (note.noteType) {
+                        NoteType.TEXT -> note.content
+                        NoteType.CHECKLIST -> {
+                            note.checklistItems
+                                ?.joinToString("\n") { item ->
+                                    val prefix = if (item.isChecked) "✅" else "☐"
+                                    "$prefix ${item.text}"
+                                } ?: ""
+                        }
+                    },
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    maxLines = 3,
+                    overflow = TextOverflow.Ellipsis
+                )
+                
+                Spacer(modifier = Modifier.height(6.dp))
+                
+                // Bottom row - KOMPAKT
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    // Timestamp - SMALLER
+                    Text(
+                        text = note.updatedAt.toReadableTime(context),
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.7f),
+                        modifier = Modifier.weight(1f)
+                    )
+                    
+                    // Sync Status - KOMPAKT
+                    if (showSyncStatus) {
+                        Spacer(modifier = Modifier.width(4.dp))
+                        
+                        Icon(
+                            imageVector = when (note.syncStatus) {
+                                SyncStatus.SYNCED -> Icons.Outlined.CloudDone
+                                SyncStatus.PENDING -> Icons.Outlined.CloudSync
+                                SyncStatus.CONFLICT -> Icons.Default.Warning
+                                SyncStatus.LOCAL_ONLY -> Icons.Outlined.CloudOff
+                            },
+                            contentDescription = null,
+                            tint = when (note.syncStatus) {
+                                SyncStatus.SYNCED -> MaterialTheme.colorScheme.primary
+                                SyncStatus.CONFLICT -> MaterialTheme.colorScheme.error
+                                else -> MaterialTheme.colorScheme.outline
+                            },
+                            modifier = Modifier.size(14.dp)
+                        )
+                    }
+                }
+            }
+            
+            // Selection indicator checkbox (top-right)
+            androidx.compose.animation.AnimatedVisibility(
+                visible = isSelectionMode,
+                enter = fadeIn() + scaleIn(),
+                exit = fadeOut() + scaleOut(),
+                modifier = Modifier
+                    .align(Alignment.TopEnd)
+                    .padding(6.dp)
+            ) {
+                Box(
+                    modifier = Modifier
+                        .size(20.dp)
+                        .clip(CircleShape)
+                        .background(
+                            if (isSelected) {
+                                MaterialTheme.colorScheme.primary
+                            } else {
+                                MaterialTheme.colorScheme.surfaceContainerHighest
+                            }
+                        )
+                        .border(
+                            width = 2.dp,
+                            color = if (isSelected) {
+                                MaterialTheme.colorScheme.primary
+                            } else {
+                                MaterialTheme.colorScheme.outline
+                            },
+                            shape = CircleShape
+                        ),
+                    contentAlignment = Alignment.Center
+                ) {
+                    if (isSelected) {
+                        Icon(
+                            imageVector = Icons.Filled.Check,
+                            contentDescription = stringResource(R.string.selection_count, 1),
+                            tint = MaterialTheme.colorScheme.onPrimary,
+                            modifier = Modifier.size(12.dp)
+                        )
+                    }
+                }
+            }
+        }
+    }
+}

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/components/NoteCardGrid.kt

@@ -0,0 +1,250 @@
+package dev.dettmer.simplenotes.ui.main.components
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.scaleIn
+import androidx.compose.animation.scaleOut
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.outlined.List
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material.icons.filled.Warning
+import androidx.compose.material.icons.outlined.CloudDone
+import androidx.compose.material.icons.outlined.CloudOff
+import androidx.compose.material.icons.outlined.CloudSync
+import androidx.compose.material.icons.outlined.Description
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import dev.dettmer.simplenotes.R
+import dev.dettmer.simplenotes.models.Note
+import dev.dettmer.simplenotes.models.NoteSize
+import dev.dettmer.simplenotes.models.NoteType
+import dev.dettmer.simplenotes.models.SyncStatus
+import dev.dettmer.simplenotes.models.getSize
+import dev.dettmer.simplenotes.utils.toReadableTime
+
+/**
+ * 🎨 v1.7.0: Unified Note Card for Grid Layout
+ * 
+ * Einheitliche Card für ALLE Notizen im Grid:
+ * - Dynamische maxLines basierend auf NoteSize
+ * - LARGE notes: 6 Zeilen Preview
+ * - SMALL notes: 3 Zeilen Preview
+ * - Kein externes Padding - Grid steuert Abstände
+ * - Optimiert für Pinterest-style dynamisches Layout
+ */
+@Composable
+fun NoteCardGrid(
+    note: Note,
+    showSyncStatus: Boolean,
+    isSelected: Boolean = false,
+    isSelectionMode: Boolean = false,
+    onClick: () -> Unit,
+    onLongClick: () -> Unit
+) {
+    val context = LocalContext.current
+    val noteSize = note.getSize()
+    
+    // Dynamische maxLines basierend auf Größe
+    val previewMaxLines = if (noteSize == NoteSize.LARGE) 6 else 3
+    
+    Card(
+        modifier = Modifier
+            .fillMaxWidth()
+            // Kein externes Padding - Grid steuert alles
+            .then(
+                if (isSelected) {
+                    Modifier.border(
+                        width = 2.dp,
+                        color = MaterialTheme.colorScheme.primary,
+                        shape = RoundedCornerShape(12.dp)
+                    )
+                } else Modifier
+            )
+            .pointerInput(note.id, isSelectionMode) {
+                detectTapGestures(
+                    onTap = { onClick() },
+                    onLongPress = { onLongClick() }
+                )
+            },
+        shape = RoundedCornerShape(12.dp),
+        elevation = CardDefaults.cardElevation(defaultElevation = 0.dp),
+        colors = CardDefaults.cardColors(
+            containerColor = if (isSelected) {
+                MaterialTheme.colorScheme.primaryContainer.copy(alpha = 0.3f)
+            } else {
+                MaterialTheme.colorScheme.surfaceContainerHigh
+            }
+        )
+    ) {
+        Box {
+            Column(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(12.dp)  // Einheitliches internes Padding
+            ) {
+                // Header row
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    // Type icon
+                    Box(
+                        modifier = Modifier
+                            .size(24.dp)
+                            .background(
+                                MaterialTheme.colorScheme.primaryContainer,
+                                CircleShape
+                            ),
+                        contentAlignment = Alignment.Center
+                    ) {
+                        Icon(
+                            imageVector = if (note.noteType == NoteType.TEXT) 
+                                Icons.Outlined.Description 
+                            else 
+                                Icons.AutoMirrored.Outlined.List,
+                            contentDescription = null,
+                            tint = MaterialTheme.colorScheme.onPrimaryContainer,
+                            modifier = Modifier.size(12.dp)
+                        )
+                    }
+                    
+                    Spacer(modifier = Modifier.width(8.dp))
+                    
+                    // Title
+                    Text(
+                        text = note.title.ifEmpty { stringResource(R.string.untitled) },
+                        style = MaterialTheme.typography.titleSmall,
+                        color = MaterialTheme.colorScheme.onSurface,
+                        maxLines = 2,
+                        overflow = TextOverflow.Ellipsis,
+                        modifier = Modifier.weight(1f)
+                    )
+                }
+                
+                Spacer(modifier = Modifier.height(6.dp))
+                
+                // Preview - Dynamische Zeilen basierend auf NoteSize
+                Text(
+                    text = when (note.noteType) {
+                        NoteType.TEXT -> note.content
+                        NoteType.CHECKLIST -> {
+                            note.checklistItems
+                                ?.joinToString("\n") { item ->
+                                    val prefix = if (item.isChecked) "✅" else "☐"
+                                    "$prefix ${item.text}"
+                                } ?: ""
+                        }
+                    },
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    maxLines = previewMaxLines,  // 🎯 Dynamisch: LARGE=6, SMALL=3
+                    overflow = TextOverflow.Ellipsis
+                )
+                
+                Spacer(modifier = Modifier.height(6.dp))
+                
+                // Footer
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    Text(
+                        text = note.updatedAt.toReadableTime(context),
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.7f),
+                        modifier = Modifier.weight(1f)
+                    )
+                    
+                    if (showSyncStatus) {
+                        Spacer(modifier = Modifier.width(4.dp))
+                        
+                        Icon(
+                            imageVector = when (note.syncStatus) {
+                                SyncStatus.SYNCED -> Icons.Outlined.CloudDone
+                                SyncStatus.PENDING -> Icons.Outlined.CloudSync
+                                SyncStatus.CONFLICT -> Icons.Default.Warning
+                                SyncStatus.LOCAL_ONLY -> Icons.Outlined.CloudOff
+                            },
+                            contentDescription = null,
+                            tint = when (note.syncStatus) {
+                                SyncStatus.SYNCED -> MaterialTheme.colorScheme.primary
+                                SyncStatus.CONFLICT -> MaterialTheme.colorScheme.error
+                                else -> MaterialTheme.colorScheme.outline
+                            },
+                            modifier = Modifier.size(14.dp)
+                        )
+                    }
+                }
+            }
+            
+            // Selection indicator checkbox (top-right)
+            androidx.compose.animation.AnimatedVisibility(
+                visible = isSelectionMode,
+                enter = fadeIn() + scaleIn(),
+                exit = fadeOut() + scaleOut(),
+                modifier = Modifier
+                    .align(Alignment.TopEnd)
+                    .padding(6.dp)
+            ) {
+                Box(
+                    modifier = Modifier
+                        .size(20.dp)
+                        .clip(CircleShape)
+                        .background(
+                            if (isSelected) {
+                                MaterialTheme.colorScheme.primary
+                            } else {
+                                MaterialTheme.colorScheme.surfaceContainerHighest
+                            }
+                        )
+                        .border(
+                            width = 2.dp,
+                            color = if (isSelected) {
+                                MaterialTheme.colorScheme.primary
+                            } else {
+                                MaterialTheme.colorScheme.outline
+                            },
+                            shape = CircleShape
+                        ),
+                    contentAlignment = Alignment.Center
+                ) {
+                    if (isSelected) {
+                        Icon(
+                            imageVector = Icons.Filled.Check,
+                            contentDescription = stringResource(R.string.selection_count, 1),
+                            tint = MaterialTheme.colorScheme.onPrimary,
+                            modifier = Modifier.size(12.dp)
+                        )
+                    }
+                }
+            }
+        }
+    }
+}

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/components/NotesList.kt

@@ -2,6 +2,7 @@ package dev.dettmer.simplenotes.ui.main.components
 
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.items
@@ -49,6 +50,8 @@ fun NotesList(
                 showSyncStatus = showSyncStatus,
                 isSelected = isSelected,
                 isSelectionMode = isSelectionMode,
+                // 🎨 v1.7.0: Padding hier in Liste (nicht in Card selbst)
+                modifier = Modifier.padding(horizontal = 16.dp, vertical = 4.dp),
                 onClick = {
                     if (isSelectionMode) {
                         // In selection mode, tap toggles selection

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/components/NotesStaggeredGrid.kt

@@ -0,0 +1,70 @@
+package dev.dettmer.simplenotes.ui.main.components
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.lazy.staggeredgrid.LazyVerticalStaggeredGrid
+import androidx.compose.foundation.lazy.staggeredgrid.LazyStaggeredGridState
+import androidx.compose.foundation.lazy.staggeredgrid.StaggeredGridCells
+import androidx.compose.foundation.lazy.staggeredgrid.items
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import dev.dettmer.simplenotes.models.Note
+import dev.dettmer.simplenotes.utils.Constants
+
+/**
+ * 🎨 v1.7.0: Staggered Grid Layout - OPTIMIERT
+ * 
+ * Pinterest-style Grid:
+ * - ALLE Items als SingleLane (halbe Breite)
+ * - Dynamische Höhe basierend auf NoteSize (LARGE=6 Zeilen, SMALL=3 Zeilen)
+ * - Keine Lücken mehr durch FullLine-Items
+ * - Selection mode support
+ * - Efficient LazyVerticalStaggeredGrid
+ */
+@Composable
+fun NotesStaggeredGrid(
+    notes: List<Note>,
+    gridState: LazyStaggeredGridState,
+    showSyncStatus: Boolean,
+    selectedNoteIds: Set<String>,
+    isSelectionMode: Boolean,
+    modifier: Modifier = Modifier,
+    onNoteClick: (Note) -> Unit,
+    onNoteLongClick: (Note) -> Unit
+) {
+    
+    LazyVerticalStaggeredGrid(
+        columns = StaggeredGridCells.Fixed(Constants.GRID_COLUMNS),
+        modifier = modifier.fillMaxSize(),
+        state = gridState,
+        // 🎨 v1.7.0: Konsistente Abstände - 16dp horizontal wie Liste, mehr Platz für FAB
+        contentPadding = PaddingValues(
+            start = 16.dp,       // Wie Liste, war 8dp
+            end = 16.dp,
+            top = 8.dp,
+            bottom = 80.dp       // Mehr Platz für FAB, war 16dp
+        ),
+        horizontalArrangement = Arrangement.spacedBy(12.dp),  // War 8dp
+        verticalItemSpacing = 12.dp                            // War Constants.GRID_SPACING_DP (8dp)
+    ) {
+        items(
+            items = notes,
+            key = { it.id }
+            // 🎨 v1.7.0: KEIN span mehr - alle Items sind SingleLane (halbe Breite)
+        ) { note ->
+            val isSelected = selectedNoteIds.contains(note.id)
+            
+            // 🎉 Einheitliche Card für alle Größen - dynamische maxLines intern
+            NoteCardGrid(
+                note = note,
+                showSyncStatus = showSyncStatus,
+                isSelected = isSelected,
+                isSelectionMode = isSelectionMode,
+                onClick = { onNoteClick(note) },
+                onLongClick = { onNoteLongClick(note) }
+            )
+        }
+    }
+}

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/SettingsNavigation.kt

@@ -7,6 +7,7 @@ import androidx.navigation.compose.composable
 import dev.dettmer.simplenotes.ui.settings.screens.AboutScreen
 import dev.dettmer.simplenotes.ui.settings.screens.BackupSettingsScreen
 import dev.dettmer.simplenotes.ui.settings.screens.DebugSettingsScreen
+import dev.dettmer.simplenotes.ui.settings.screens.DisplaySettingsScreen
 import dev.dettmer.simplenotes.ui.settings.screens.LanguageSettingsScreen
 import dev.dettmer.simplenotes.ui.settings.screens.MarkdownSettingsScreen
 import dev.dettmer.simplenotes.ui.settings.screens.ServerSettingsScreen
@@ -95,5 +96,13 @@ fun SettingsNavHost(
                 onBack = { navController.popBackStack() }
             )
         }
+        
+        // 🎨 v1.7.0: Display Settings
+        composable(SettingsRoute.Display.route) {
+            DisplaySettingsScreen(
+                viewModel = viewModel,
+                onBack = { navController.popBackStack() }
+            )
+        }
     }
 }

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/SettingsRoute.kt

@@ -13,4 +13,5 @@ sealed class SettingsRoute(val route: String) {
     data object Backup : SettingsRoute("settings_backup")
     data object About : SettingsRoute("settings_about")
     data object Debug : SettingsRoute("settings_debug")
+    data object Display : SettingsRoute("settings_display")  // 🎨 v1.7.0
 }

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/SettingsViewModel.kt

@@ -9,6 +9,7 @@ import androidx.lifecycle.viewModelScope
 import dev.dettmer.simplenotes.R
 import dev.dettmer.simplenotes.backup.BackupManager
 import dev.dettmer.simplenotes.backup.RestoreMode
+import dev.dettmer.simplenotes.storage.NotesStorage
 import dev.dettmer.simplenotes.sync.WebDavSyncService
 import dev.dettmer.simplenotes.utils.Constants
 import dev.dettmer.simplenotes.utils.Logger
@@ -33,6 +34,7 @@ import java.net.URL
  * 
  * Manages all settings state and actions across the Settings navigation graph.
  */
+@Suppress("TooManyFunctions") // v1.7.0: 35 Funktionen durch viele kleine Setter (setTrigger*, set*)
 class SettingsViewModel(application: Application) : AndroidViewModel(application) {
     
     companion object {
@@ -42,6 +44,11 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
     
     private val prefs = application.getSharedPreferences(Constants.PREFS_NAME, Context.MODE_PRIVATE)
     val backupManager = BackupManager(application)
+    private val notesStorage = NotesStorage(application) // v1.7.0: For server change detection
+    
+    // 🔧 v1.7.0 Hotfix: Track last confirmed server URL for change detection
+    // This prevents false-positive "server changed" toasts during text input
+    private var confirmedServerUrl: String = prefs.getString(Constants.KEY_SERVER_URL, "") ?: ""
     
     // ═══════════════════════════════════════════════════════════════════════
     // Server Settings State
@@ -154,6 +161,12 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
     )
     val triggerBoot: StateFlow<Boolean> = _triggerBoot.asStateFlow()
     
+    // 🎉 v1.7.0: WiFi-Only Sync Toggle
+    private val _wifiOnlySync = MutableStateFlow(
+        prefs.getBoolean(Constants.KEY_WIFI_ONLY_SYNC, Constants.DEFAULT_WIFI_ONLY_SYNC)
+    )
+    val wifiOnlySync: StateFlow<Boolean> = _wifiOnlySync.asStateFlow()
+    
     // ═══════════════════════════════════════════════════════════════════════
     // Markdown Settings State
     // ═══════════════════════════════════════════════════════════════════════
@@ -173,6 +186,15 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
     )
     val fileLoggingEnabled: StateFlow<Boolean> = _fileLoggingEnabled.asStateFlow()
     
+    // ═══════════════════════════════════════════════════════════════════════
+    // 🎨 v1.7.0: Display Settings State
+    // ═══════════════════════════════════════════════════════════════════════
+    
+    private val _displayMode = MutableStateFlow(
+        prefs.getString(Constants.KEY_DISPLAY_MODE, Constants.DEFAULT_DISPLAY_MODE) ?: Constants.DEFAULT_DISPLAY_MODE
+    )
+    val displayMode: StateFlow<String> = _displayMode.asStateFlow()
+    
     // ═══════════════════════════════════════════════════════════════════════
     // UI State
     // ═══════════════════════════════════════════════════════════════════════
@@ -216,41 +238,130 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
     /**
      * 🌟 v1.6.0: Update only the host part of the server URL
      * The protocol prefix is handled separately by updateProtocol()
+     * 🔧 v1.7.0 Hotfix: Removed auto-save to prevent false server-change detection
+     * 🔧 v1.7.0 Regression Fix: Restore immediate SharedPrefs write (for WebDavSyncService)
+     *    but WITHOUT server-change detection (detection happens only on screen exit)
      */
     fun updateServerHost(host: String) {
         _serverHost.value = host
-        saveServerSettings()
+        
+        // ✅ Save immediately for WebDavSyncService, but WITHOUT server-change detection
+        val prefix = if (_isHttps.value) "https://" else "http://"
+        val fullUrl = if (host.isEmpty()) "" else prefix + host
+        prefs.edit().putString(Constants.KEY_SERVER_URL, fullUrl).apply()
     }
     
     fun updateProtocol(useHttps: Boolean) {
         _isHttps.value = useHttps
         // 🌟 v1.6.0: Host stays the same, only prefix changes
-        saveServerSettings()
+        // 🔧 v1.7.0 Hotfix: Removed auto-save to prevent false server-change detection
+        // 🔧 v1.7.0 Regression Fix: Restore immediate SharedPrefs write (for WebDavSyncService)
+        
+        // ✅ Save immediately for WebDavSyncService, but WITHOUT server-change detection
+        val prefix = if (useHttps) "https://" else "http://"
+        val fullUrl = if (_serverHost.value.isEmpty()) "" else prefix + _serverHost.value
+        prefs.edit().putString(Constants.KEY_SERVER_URL, fullUrl).apply()
     }
     
     fun updateUsername(value: String) {
         _username.value = value
-        saveServerSettings()
+        // 🔧 v1.7.0 Regression Fix: Restore immediate SharedPrefs write (for WebDavSyncService)
+        prefs.edit().putString(Constants.KEY_USERNAME, value).apply()
     }
     
     fun updatePassword(value: String) {
         _password.value = value
-        saveServerSettings()
+        // 🔧 v1.7.0 Regression Fix: Restore immediate SharedPrefs write (for WebDavSyncService)
+        prefs.edit().putString(Constants.KEY_PASSWORD, value).apply()
     }
     
-    private fun saveServerSettings() {
+    /**
+     * 🔧 v1.7.0 Hotfix: Manual save function - only called when leaving settings screen
+     * This prevents false "server changed" detection during text input
+     * 🔧 v1.7.0 Regression Fix: Settings are now saved IMMEDIATELY in update functions.
+     *    This function now ONLY handles server-change detection and sync reset.
+     */
+    fun saveServerSettingsManually() {
         // 🌟 v1.6.0: Construct full URL from prefix + host
         val prefix = if (_isHttps.value) "https://" else "http://"
         val fullUrl = if (_serverHost.value.isEmpty()) "" else prefix + _serverHost.value
         
-        prefs.edit().apply {
-            putString(Constants.KEY_SERVER_URL, fullUrl)
-            putString(Constants.KEY_USERNAME, _username.value)
-            putString(Constants.KEY_PASSWORD, _password.value)
-            apply()
+        // 🔄 v1.7.0: Detect server change ONLY against last confirmed URL
+        val serverChanged = isServerReallyChanged(confirmedServerUrl, fullUrl)
+        
+        // ✅ Settings are already saved in updateServerHost/Protocol/Username/Password
+        // This function now ONLY handles server-change detection
+        
+        // Reset sync status if server actually changed
+        if (serverChanged) {
+            viewModelScope.launch {
+                val count = notesStorage.resetAllSyncStatusToPending()
+                Logger.d(TAG, "🔄 Server changed from '$confirmedServerUrl' to '$fullUrl': Reset $count notes to PENDING")
+                emitToast(getString(R.string.toast_server_changed_sync_reset, count))
+            }
+            // Update confirmed state after reset
+            confirmedServerUrl = fullUrl
+        } else {
+            Logger.d(TAG, "💾 Server settings check complete (no server change detected)")
         }
     }
     
+    /**
+     * <20> v1.7.0 Hotfix: Improved server change detection
+     * 
+     * Only returns true if the server URL actually changed in a meaningful way.
+     * Handles edge cases:
+     * - First setup (empty → filled) = NOT a change
+     * - Protocol only (http → https) = NOT a change
+     * - Server removed (filled → empty) = NOT a change
+     * - Trailing slashes, case differences = NOT a change
+     * - Different hostname/port/path = IS a change ✓
+     */
+    private fun isServerReallyChanged(confirmedUrl: String, newUrl: String): Boolean {
+        // Empty → Non-empty = First setup, NOT a change
+        if (confirmedUrl.isEmpty() && newUrl.isNotEmpty()) {
+            Logger.d(TAG, "First server setup detected (no reset needed)")
+            return false
+        }
+        
+        // Both empty = No change
+        if (confirmedUrl.isEmpty() && newUrl.isEmpty()) {
+            return false
+        }
+        
+        // Non-empty → Empty = Server removed (keep notes local, no reset)
+        if (confirmedUrl.isNotEmpty() && newUrl.isEmpty()) {
+            Logger.d(TAG, "Server removed (notes stay local, no reset needed)")
+            return false
+        }
+        
+        // Same URL = No change
+        if (confirmedUrl == newUrl) {
+            return false
+        }
+        
+        // Normalize URLs for comparison (ignore protocol, trailing slash, case)
+        val normalize = { url: String ->
+            url.trim()
+                .removePrefix("http://")
+                .removePrefix("https://")
+                .removeSuffix("/")
+                .lowercase()
+        }
+        
+        val confirmedNormalized = normalize(confirmedUrl)
+        val newNormalized = normalize(newUrl)
+        
+        // Check if normalized URLs differ
+        val changed = confirmedNormalized != newNormalized
+        
+        if (changed) {
+            Logger.d(TAG, "Server URL changed: '$confirmedNormalized' → '$newNormalized'")
+        }
+        
+        return changed
+    }
+    
     fun testConnection() {
         viewModelScope.launch {
             _serverStatus.value = ServerStatus.Checking
@@ -412,6 +523,16 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
         Logger.d(TAG, "Trigger Boot: $enabled")
     }
     
+    /**
+     * 🎉 v1.7.0: Set WiFi-only sync mode
+     * When enabled, sync only happens when connected to WiFi
+     */
+    fun setWifiOnlySync(enabled: Boolean) {
+        _wifiOnlySync.value = enabled
+        prefs.edit().putBoolean(Constants.KEY_WIFI_ONLY_SYNC, enabled).apply()
+        Logger.d(TAG, "📡 WiFi-only sync: $enabled")
+    }
+    
     // ═══════════════════════════════════════════════════════════════════════
     // Markdown Settings Actions
     // ═══════════════════════════════════════════════════════════════════════
@@ -519,11 +640,11 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
     // Backup Actions
     // ═══════════════════════════════════════════════════════════════════════
     
-    fun createBackup(uri: Uri) {
+    fun createBackup(uri: Uri, password: String? = null) {
         viewModelScope.launch {
             _isBackupInProgress.value = true
             try {
-                val result = backupManager.createBackup(uri)
+                val result = backupManager.createBackup(uri, password)
                 val message = if (result.success) {
                     getString(R.string.toast_backup_success, result.message ?: "")
                 } else {
@@ -538,11 +659,11 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
         }
     }
     
-    fun restoreFromFile(uri: Uri, mode: RestoreMode) {
+    fun restoreFromFile(uri: Uri, mode: RestoreMode, password: String? = null) {
         viewModelScope.launch {
             _isBackupInProgress.value = true
             try {
-                val result = backupManager.restoreBackup(uri, mode)
+                val result = backupManager.restoreBackup(uri, mode, password)
                 val message = if (result.success) {
                     getString(R.string.toast_restore_success, result.importedNotes)
                 } else {
@@ -557,6 +678,29 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
         }
     }
     
+    /**
+     * 🔐 v1.7.0: Check if backup is encrypted and call appropriate callback
+     */
+    fun checkBackupEncryption(
+        uri: Uri,
+        onEncrypted: () -> Unit,
+        onPlaintext: () -> Unit
+    ) {
+        viewModelScope.launch {
+            try {
+                val isEncrypted = backupManager.isBackupEncrypted(uri)
+                if (isEncrypted) {
+                    onEncrypted()
+                } else {
+                    onPlaintext()
+                }
+            } catch (e: Exception) {
+                Logger.e(TAG, "Failed to check encryption status", e)
+                onPlaintext()  // Assume plaintext on error
+            }
+        }
+    }
+    
     fun restoreFromServer(mode: RestoreMode) {
         viewModelScope.launch {
             _isBackupInProgress.value = true
@@ -664,4 +808,17 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
         val total: Int,
         val isComplete: Boolean = false
     )
+    
+    // ═══════════════════════════════════════════════════════════════════════
+    // 🎨 v1.7.0: Display Mode Functions
+    // ═══════════════════════════════════════════════════════════════════════
+    
+    /**
+     * Set display mode (list or grid)
+     */
+    fun setDisplayMode(mode: String) {
+        _displayMode.value = mode
+        prefs.edit().putString(Constants.KEY_DISPLAY_MODE, mode).apply()
+        Logger.d(TAG, "Display mode changed to: $mode")
+    }
 }

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/components/BackupPasswordDialog.kt

@@ -0,0 +1,180 @@
+package dev.dettmer.simplenotes.ui.settings.components
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Visibility
+import androidx.compose.material.icons.filled.VisibilityOff
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.focus.FocusRequester
+import androidx.compose.ui.focus.focusRequester
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.text.input.VisualTransformation
+import androidx.compose.ui.unit.dp
+import dev.dettmer.simplenotes.R
+
+private const val MIN_PASSWORD_LENGTH = 8
+
+/**
+ * 🔒 v1.7.0: Password input dialog for backup encryption/decryption
+ */
+@Composable
+fun BackupPasswordDialog(
+    title: String,
+    onDismiss: () -> Unit,
+    onConfirm: (password: String) -> Unit,
+    requireConfirmation: Boolean = true
+) {
+    var password by remember { mutableStateOf("") }
+    var confirmPassword by remember { mutableStateOf("") }
+    var passwordVisible by remember { mutableStateOf(false) }
+    var confirmPasswordVisible by remember { mutableStateOf(false) }
+    var errorMessage by remember { mutableStateOf<String?>(null) }
+    
+    val focusRequester = remember { FocusRequester() }
+    
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(title) },
+        text = {
+            Column {
+                // Password field
+                OutlinedTextField(
+                    value = password,
+                    onValueChange = { 
+                        password = it
+                        errorMessage = null
+                    },
+                    label = { Text(stringResource(R.string.backup_encryption_password)) },
+                    placeholder = { Text(stringResource(R.string.backup_encryption_password_hint)) },
+                    visualTransformation = if (passwordVisible) VisualTransformation.None else PasswordVisualTransformation(),
+                    trailingIcon = {
+                        IconButton(onClick = { passwordVisible = !passwordVisible }) {
+                            Icon(
+                                imageVector = if (passwordVisible) Icons.Filled.Visibility else Icons.Filled.VisibilityOff,
+                                contentDescription = null
+                            )
+                        }
+                    },
+                    keyboardOptions = KeyboardOptions(
+                        keyboardType = KeyboardType.Password,
+                        imeAction = if (requireConfirmation) ImeAction.Next else ImeAction.Done
+                    ),
+                    keyboardActions = KeyboardActions(
+                        onDone = if (!requireConfirmation) {
+                            { validateAndConfirm(password, null, onConfirm) { errorMessage = it } }
+                        } else null
+                    ),
+                    singleLine = true,
+                    isError = errorMessage != null,
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .focusRequester(focusRequester)
+                )
+                
+                // Confirm password field (only for encryption, not decryption)
+                if (requireConfirmation) {
+                    Spacer(modifier = Modifier.height(8.dp))
+                    
+                    OutlinedTextField(
+                        value = confirmPassword,
+                        onValueChange = { 
+                            confirmPassword = it
+                            errorMessage = null
+                        },
+                        label = { Text(stringResource(R.string.backup_encryption_confirm)) },
+                        placeholder = { Text(stringResource(R.string.backup_encryption_confirm_hint)) },
+                        visualTransformation = if (confirmPasswordVisible) VisualTransformation.None else PasswordVisualTransformation(),
+                        trailingIcon = {
+                            IconButton(onClick = { confirmPasswordVisible = !confirmPasswordVisible }) {
+                                Icon(
+                                    imageVector = if (confirmPasswordVisible) Icons.Filled.Visibility else Icons.Filled.VisibilityOff,
+                                    contentDescription = null
+                                )
+                            }
+                        },
+                        keyboardOptions = KeyboardOptions(
+                            keyboardType = KeyboardType.Password,
+                            imeAction = ImeAction.Done
+                        ),
+                        keyboardActions = KeyboardActions(
+                            onDone = { validateAndConfirm(password, confirmPassword, onConfirm) { errorMessage = it } }
+                        ),
+                        singleLine = true,
+                        isError = errorMessage != null,
+                        modifier = Modifier.fillMaxWidth()
+                    )
+                }
+                
+                // Error message
+                if (errorMessage != null) {
+                    Spacer(modifier = Modifier.height(4.dp))
+                    Text(
+                        text = errorMessage!!,
+                        color = androidx.compose.material3.MaterialTheme.colorScheme.error,
+                        style = androidx.compose.material3.MaterialTheme.typography.bodySmall
+                    )
+                }
+            }
+        },
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    validateAndConfirm(
+                        password,
+                        if (requireConfirmation) confirmPassword else null,
+                        onConfirm
+                    ) { errorMessage = it }
+                }
+            ) {
+                Text("OK")
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) {
+                Text(stringResource(android.R.string.cancel))
+            }
+        }
+    )
+}
+
+/**
+ * Validate password and call onConfirm if valid
+ */
+private fun validateAndConfirm(
+    password: String,
+    confirmPassword: String?,
+    onConfirm: (String) -> Unit,
+    onError: (String) -> Unit
+) {
+    when {
+        password.length < MIN_PASSWORD_LENGTH -> {
+            onError("Password too short (min. $MIN_PASSWORD_LENGTH characters)")
+        }
+        confirmPassword != null && password != confirmPassword -> {
+            onError("Passwords don't match")
+        }
+        else -> {
+            onConfirm(password)
+        }
+    }
+}

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/screens/BackupSettingsScreen.kt

@@ -26,6 +26,7 @@ import androidx.compose.ui.unit.dp
 import dev.dettmer.simplenotes.R
 import dev.dettmer.simplenotes.backup.RestoreMode
 import dev.dettmer.simplenotes.ui.settings.SettingsViewModel
+import dev.dettmer.simplenotes.ui.settings.components.BackupPasswordDialog
 import dev.dettmer.simplenotes.ui.settings.components.RadioOption
 import dev.dettmer.simplenotes.ui.settings.components.SettingsButton
 import dev.dettmer.simplenotes.ui.settings.components.SettingsDivider
@@ -34,6 +35,7 @@ import dev.dettmer.simplenotes.ui.settings.components.SettingsOutlinedButton
 import dev.dettmer.simplenotes.ui.settings.components.SettingsRadioGroup
 import dev.dettmer.simplenotes.ui.settings.components.SettingsScaffold
 import dev.dettmer.simplenotes.ui.settings.components.SettingsSectionHeader
+import dev.dettmer.simplenotes.ui.settings.components.SettingsSwitch
 import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.Locale
@@ -58,11 +60,25 @@ fun BackupSettingsScreen(
     var pendingRestoreUri by remember { mutableStateOf<Uri?>(null) }
     var selectedRestoreMode by remember { mutableStateOf(RestoreMode.MERGE) }
     
+    // 🔐 v1.7.0: Encryption state
+    var encryptBackup by remember { mutableStateOf(false) }
+    var showEncryptionPasswordDialog by remember { mutableStateOf(false) }
+    var showDecryptionPasswordDialog by remember { mutableStateOf(false) }
+    var pendingBackupUri by remember { mutableStateOf<Uri?>(null) }
+    
     // File picker launchers
     val createBackupLauncher = rememberLauncherForActivityResult(
         contract = ActivityResultContracts.CreateDocument("application/json")
     ) { uri ->
-        uri?.let { viewModel.createBackup(it) }
+        uri?.let {
+            // 🔐 v1.7.0: If encryption enabled, show password dialog first
+            if (encryptBackup) {
+                pendingBackupUri = it
+                showEncryptionPasswordDialog = true
+            } else {
+                viewModel.createBackup(it, password = null)
+            }
+        }
     }
     
     val restoreFileLauncher = rememberLauncherForActivityResult(
@@ -99,6 +115,16 @@ fun BackupSettingsScreen(
             
             Spacer(modifier = Modifier.height(8.dp))
             
+            // 🔐 v1.7.0: Encryption toggle
+            SettingsSwitch(
+                title = stringResource(R.string.backup_encryption_title),
+                subtitle = stringResource(R.string.backup_encryption_subtitle),
+                checked = encryptBackup,
+                onCheckedChange = { encryptBackup = it }
+            )
+            
+            Spacer(modifier = Modifier.height(8.dp))
+            
             SettingsButton(
                 text = stringResource(R.string.backup_create),
                 onClick = {
@@ -156,6 +182,47 @@ fun BackupSettingsScreen(
         }
     }
     
+    // 🔐 v1.7.0: Encryption password dialog (for backup creation)
+    if (showEncryptionPasswordDialog) {
+        BackupPasswordDialog(
+            title = stringResource(R.string.backup_encryption_title),
+            onDismiss = {
+                showEncryptionPasswordDialog = false
+                pendingBackupUri = null
+            },
+            onConfirm = { password ->
+                showEncryptionPasswordDialog = false
+                pendingBackupUri?.let { uri ->
+                    viewModel.createBackup(uri, password)
+                }
+                pendingBackupUri = null
+            },
+            requireConfirmation = true
+        )
+    }
+    
+    // 🔐 v1.7.0: Decryption password dialog (for restore)
+    if (showDecryptionPasswordDialog) {
+        BackupPasswordDialog(
+            title = stringResource(R.string.backup_decryption_required),
+            onDismiss = {
+                showDecryptionPasswordDialog = false
+                pendingRestoreUri = null
+            },
+            onConfirm = { password ->
+                showDecryptionPasswordDialog = false
+                pendingRestoreUri?.let { uri ->
+                    when (restoreSource) {
+                        RestoreSource.LocalFile -> viewModel.restoreFromFile(uri, selectedRestoreMode, password)
+                        RestoreSource.Server -> { /* Server restore doesn't support encryption */ }
+                    }
+                }
+                pendingRestoreUri = null
+            },
+            requireConfirmation = false
+        )
+    }
+    
     // Restore Mode Dialog
     if (showRestoreDialog) {
         RestoreModeDialog(
@@ -167,7 +234,17 @@ fun BackupSettingsScreen(
                 when (restoreSource) {
                     RestoreSource.LocalFile -> {
                         pendingRestoreUri?.let { uri ->
-                            viewModel.restoreFromFile(uri, selectedRestoreMode)
+                            // 🔐 v1.7.0: Check if backup is encrypted
+                            viewModel.checkBackupEncryption(
+                                uri = uri,
+                                onEncrypted = {
+                                    showDecryptionPasswordDialog = true
+                                },
+                                onPlaintext = {
+                                    viewModel.restoreFromFile(uri, selectedRestoreMode, password = null)
+                                    pendingRestoreUri = null
+                                }
+                            )
                         }
                     }
                     RestoreSource.Server -> {

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/screens/DebugSettingsScreen.kt

@@ -82,6 +82,9 @@ fun DebugSettingsScreen(
             Spacer(modifier = Modifier.height(8.dp))
             
             // Export Logs Button
+            val logsSubject = stringResource(R.string.debug_logs_subject)
+            val logsShareVia = stringResource(R.string.debug_logs_share_via)
+            
             SettingsButton(
                 text = stringResource(R.string.debug_export_logs),
                 onClick = {
@@ -96,11 +99,11 @@ fun DebugSettingsScreen(
                         val shareIntent = Intent(Intent.ACTION_SEND).apply {
                             type = "text/plain"
                             putExtra(Intent.EXTRA_STREAM, logUri)
-                            putExtra(Intent.EXTRA_SUBJECT, context.getString(R.string.debug_logs_subject))
+                            putExtra(Intent.EXTRA_SUBJECT, logsSubject)
                             addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
                         }
                         
-                        context.startActivity(Intent.createChooser(shareIntent, context.getString(R.string.debug_logs_share_via)))
+                        context.startActivity(Intent.createChooser(shareIntent, logsShareVia))
                     }
                 },
                 modifier = Modifier.padding(horizontal = 16.dp)

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/screens/DisplaySettingsScreen.kt

@@ -0,0 +1,74 @@
+package dev.dettmer.simplenotes.ui.settings.screens
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import dev.dettmer.simplenotes.R
+import dev.dettmer.simplenotes.ui.settings.SettingsViewModel
+import dev.dettmer.simplenotes.ui.settings.components.RadioOption
+import dev.dettmer.simplenotes.ui.settings.components.SettingsInfoCard
+import dev.dettmer.simplenotes.ui.settings.components.SettingsRadioGroup
+import dev.dettmer.simplenotes.ui.settings.components.SettingsScaffold
+import dev.dettmer.simplenotes.ui.settings.components.SettingsSectionHeader
+
+/**
+ * 🎨 v1.7.0: Display Settings Screen
+ * 
+ * Allows switching between List and Grid view modes.
+ */
+@Composable
+fun DisplaySettingsScreen(
+    viewModel: SettingsViewModel,
+    onBack: () -> Unit
+) {
+    val displayMode by viewModel.displayMode.collectAsState()
+    
+    SettingsScaffold(
+        title = stringResource(R.string.display_settings_title),
+        onBack = onBack
+    ) { paddingValues ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(paddingValues)
+                .verticalScroll(rememberScrollState())
+        ) {
+            Spacer(modifier = Modifier.height(8.dp))
+            
+            SettingsSectionHeader(text = stringResource(R.string.display_mode_title))
+            
+            SettingsRadioGroup(
+                options = listOf(
+                    RadioOption(
+                        value = "list",
+                        title = stringResource(R.string.display_mode_list),
+                        subtitle = null
+                    ),
+                    RadioOption(
+                        value = "grid",
+                        title = stringResource(R.string.display_mode_grid),
+                        subtitle = null
+                    )
+                ),
+                selectedValue = displayMode,
+                onValueSelected = { viewModel.setDisplayMode(it) }
+            )
+            
+            SettingsInfoCard(
+                text = stringResource(R.string.display_mode_info)
+            )
+            
+            Spacer(modifier = Modifier.height(16.dp))
+        }
+    }
+}

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/screens/ServerSettingsScreen.kt

@@ -33,6 +33,7 @@ import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
@@ -56,6 +57,7 @@ import dev.dettmer.simplenotes.ui.settings.components.SettingsScaffold
  * Server configuration settings screen
  * v1.5.0: Jetpack Compose Settings Redesign
  * v1.6.0: Offline Mode Toggle
+ * v1.7.0 Hotfix: Save settings on screen exit (not on every keystroke)
  */
 @Suppress("LongMethod", "MagicNumber") // Compose UI + Color hex values
 @Composable
@@ -74,6 +76,14 @@ fun ServerSettingsScreen(
     
     var passwordVisible by remember { mutableStateOf(false) }
     
+    // 🔧 v1.7.0 Hotfix: Save server settings when leaving this screen
+    // This prevents false "server changed" detection during text input
+    DisposableEffect(Unit) {
+        onDispose {
+            viewModel.saveServerSettingsManually()
+        }
+    }
+    
     // Check server status on load (only if not in offline mode)
     LaunchedEffect(offlineMode) {
         if (!offlineMode) {

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/screens/SettingsMainScreen.kt

@@ -10,6 +10,7 @@ import androidx.compose.material.icons.filled.Backup
 import androidx.compose.material.icons.filled.BugReport
 import androidx.compose.material.icons.filled.Cloud
 import androidx.compose.material.icons.filled.Description
+import androidx.compose.material.icons.filled.GridView
 import androidx.compose.material.icons.filled.Info
 import androidx.compose.material.icons.filled.Language
 import androidx.compose.material.icons.filled.Sync
@@ -90,6 +91,22 @@ fun SettingsMainScreen(
                 )
             }
             
+            // 🎨 v1.7.0: Display Settings
+            item {
+                val displayMode by viewModel.displayMode.collectAsState()
+                val displaySubtitle = when (displayMode) {
+                    "grid" -> stringResource(R.string.display_mode_grid)
+                    else -> stringResource(R.string.display_mode_list)
+                }
+                
+                SettingsCard(
+                    icon = Icons.Default.GridView,
+                    title = stringResource(R.string.display_settings_title),
+                    subtitle = displaySubtitle,
+                    onClick = { onNavigate(SettingsRoute.Display) }
+                )
+            }
+            
             // Server-Einstellungen
             item {
                 // 🌟 v1.6.0: Check if server is configured (host is not empty)

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/screens/SyncSettingsScreen.kt

@@ -50,6 +50,9 @@ fun SyncSettingsScreen(
     val triggerBoot by viewModel.triggerBoot.collectAsState()
     val syncInterval by viewModel.syncInterval.collectAsState()
     
+    // 🆕 v1.7.0: WiFi-only sync
+    val wifiOnlySync by viewModel.wifiOnlySync.collectAsState()
+    
     // Check if server is configured
     val isServerConfigured = viewModel.isServerConfigured()
     
@@ -108,6 +111,16 @@ fun SyncSettingsScreen(
                 enabled = isServerConfigured
             )
             
+            // 🆕 v1.7.0: WiFi-Only Sync Toggle
+            SettingsSwitch(
+                title = stringResource(R.string.sync_wifi_only_title),
+                subtitle = stringResource(R.string.sync_wifi_only_subtitle),
+                checked = wifiOnlySync,
+                onCheckedChange = { viewModel.setWifiOnlySync(it) },
+                icon = Icons.Default.Wifi,
+                enabled = isServerConfigured
+            )
+            
             SettingsDivider()
             
             // ═══════════════════════════════════════════════════════════════

android/app/src/main/java/dev/dettmer/simplenotes/utils/Constants.kt

@@ -32,6 +32,10 @@ object Constants {
     // 🔥 v1.6.0: Offline Mode Toggle
     const val KEY_OFFLINE_MODE = "offline_mode_enabled"
     
+    // 🔥 v1.7.0: WiFi-Only Sync Toggle
+    const val KEY_WIFI_ONLY_SYNC = "wifi_only_sync_enabled"
+    const val DEFAULT_WIFI_ONLY_SYNC = false  // Standardmäßig auch mobil syncen
+    
     // 🔥 v1.6.0: Configurable Sync Triggers
     const val KEY_SYNC_TRIGGER_ON_SAVE = "sync_trigger_on_save"
     const val KEY_SYNC_TRIGGER_ON_RESUME = "sync_trigger_on_resume"
@@ -57,4 +61,10 @@ object Constants {
     // Notifications
     const val NOTIFICATION_CHANNEL_ID = "notes_sync_channel"
     const val NOTIFICATION_ID = 1001
+    
+    // 🎨 v1.7.0: Staggered Grid Layout
+    const val KEY_DISPLAY_MODE = "display_mode" // "list" or "grid"
+    const val DEFAULT_DISPLAY_MODE = "list"
+    const val GRID_COLUMNS = 2
+    const val GRID_SPACING_DP = 8
 }

android/app/src/main/res/values-de/strings.xml

@@ -23,6 +23,7 @@
     <!-- ============================= -->
     <!-- EMPTY STATE                   -->
     <!-- ============================= -->
+    <string name="empty_state_emoji">📝</string>
     <string name="empty_state_title">Noch keine Notizen</string>
     <string name="empty_state_message">Tippe + um eine neue Notiz zu erstellen</string>
     
@@ -196,11 +197,11 @@
     <string name="sync_interval_section">Sync-Intervall</string>
     <string name="sync_interval_info">Legt fest, wie oft die App im Hintergrund synchronisiert. Kürzere Intervalle bedeuten aktuellere Daten, verbrauchen aber etwas mehr Akku.\n\n⏱️ Hinweis: Wenn dein Smartphone im Standby ist, kann Android die Synchronisation verzögern (bis zu 60 Min.), um Akku zu sparen. Das ist normal und betrifft alle Hintergrund-Apps.</string>
     <string name="sync_interval_15min_title">⚡ Alle 15 Minuten</string>
-    <string name="sync_interval_15min_subtitle">Schnellste Synchronisation • ~0.8% Akku/Tag (~23 mAh)</string>
+    <string name="sync_interval_15min_subtitle">Schnellste Synchronisation • ~0.8%% Akku/Tag (~23 mAh)</string>
     <string name="sync_interval_30min_title">✓ Alle 30 Minuten (Empfohlen)</string>
-    <string name="sync_interval_30min_subtitle">Ausgewogenes Verhältnis • ~0.4% Akku/Tag (~12 mAh)</string>
+    <string name="sync_interval_30min_subtitle">Ausgewogenes Verhältnis • ~0.4%% Akku/Tag (~12 mAh)</string>
     <string name="sync_interval_60min_title">🔋 Alle 60 Minuten</string>
-    <string name="sync_interval_60min_subtitle">Maximale Akkulaufzeit • ~0.2% Akku/Tag (~6 mAh geschätzt)</string>
+    <string name="sync_interval_60min_subtitle">Maximale Akkulaufzeit • ~0.2%% Akku/Tag (~6 mAh geschätzt)</string>
     <!-- Legacy -->
     <string name="auto_sync_info">ℹ️ Auto-Sync:\n\n• Prüft alle 30 Min ob Server erreichbar\n• Funktioniert bei jeder WiFi-Verbindung\n• Läuft auch im Hintergrund\n• Minimaler Akkuverbrauch (~0.4%%/Tag)</string>
     
@@ -224,6 +225,11 @@
     <string name="sync_trigger_boot_title">Nach Gerät-Neustart</string>
     <string name="sync_trigger_boot_subtitle">Startet Hintergrund-Sync nach Reboot</string>
     
+    <!-- 🆕 v1.7.0: WiFi-Only Sync -->
+    <string name="sync_wifi_only_title">Sync nur im WLAN</string>
+    <string name="sync_wifi_only_subtitle">Sync wird nur durchgeführt wenn WLAN verbunden ist. Spart mobiles Datenvolumen und verhindert lange Wartezeit.</string>
+    <string name="sync_wifi_only_hint">Sync nur im WLAN möglich</string>
+    
     <string name="sync_manual_hint">Manueller Sync (Toolbar/Pull-to-Refresh) ist ebenfalls verfügbar.</string>
     <string name="sync_manual_hint_disabled">Sync ist im Offline-Modus nicht verfügbar.</string>
     
@@ -253,6 +259,20 @@
     <string name="backup_local_section">Lokales Backup</string>
     <string name="backup_create">💾 Backup erstellen</string>
     <string name="backup_restore_file">📂 Aus Datei wiederherstellen</string>
+    
+    <!-- 🔐 v1.7.0: Verschlüsselung -->
+    <string name="backup_encryption_title">Backup verschlüsseln</string>
+    <string name="backup_encryption_subtitle">Schütze deine Backup-Datei mit Passwort</string>
+    <string name="backup_encryption_password">Passwort</string>
+    <string name="backup_encryption_password_hint">Passwort eingeben (min. 8 Zeichen)</string>
+    <string name="backup_encryption_confirm">Passwort bestätigen</string>
+    <string name="backup_encryption_confirm_hint">Passwort erneut eingeben</string>
+    <string name="backup_encryption_error_mismatch">Passwörter stimmen nicht überein</string>
+    <string name="backup_encryption_error_too_short">Passwort zu kurz (min. 8 Zeichen)</string>
+    <string name="backup_decryption_required">🔒 Verschlüsseltes Backup</string>
+    <string name="backup_decryption_password">Passwort zum Entschlüsseln eingeben</string>
+    <string name="backup_decryption_error">❌ Entschlüsselung fehlgeschlagen. Falsches Passwort?</string>
+    
     <string name="backup_server_section">Server-Backup</string>
     <string name="backup_restore_server">☁️ Vom Server wiederherstellen</string>
     <string name="backup_restore_dialog_title">⚠️ Backup wiederherstellen?</string>
@@ -308,6 +328,15 @@
     <string name="language_info">ℹ️ Wähle deine bevorzugte Sprache. Die App wird neu gestartet, um die Änderung anzuwenden.</string>
     <string name="language_changed_restart">Sprache geändert. Neustart…</string>
     
+    <!-- ============================= -->
+    <!-- SETTINGS - DISPLAY            -->
+    <!-- ============================= -->
+    <string name="display_settings_title">Anzeige</string>
+    <string name="display_mode_title">Notizen-Ansicht</string>
+    <string name="display_mode_list">📋 Listen-Ansicht</string>
+    <string name="display_mode_grid">🎨 Raster-Ansicht</string>
+    <string name="display_mode_info">Die Raster-Ansicht zeigt Notizen im Pinterest-Stil. Kurze Notizen erscheinen nebeneinander, lange Notizen nehmen die volle Breite ein.</string>
+    
     <!-- ============================= -->
     <!-- SETTINGS - ABOUT              -->
     <!-- ============================= -->
@@ -357,6 +386,8 @@
     <string name="toast_logs_deleted">🗑️ Logs gelöscht</string>
     <string name="toast_no_logs_to_delete">📭 Keine Logs zum Löschen</string>
     <string name="toast_logs_delete_error">❌ Fehler beim Löschen: %s</string>
+    <!-- 🔄 v1.7.0: Server change notification -->
+    <string name="toast_server_changed_sync_reset">🔄 Server geändert. %d Notizen werden beim nächsten Sync hochgeladen.</string>
     <string name="toast_link_error">❌ Fehler beim Öffnen des Links</string>
     <string name="toast_file_logging_enabled">📝 Datei-Logging aktiviert</string>
     <string name="toast_file_logging_disabled">📝 Datei-Logging deaktiviert</string>

android/app/src/main/res/values/strings.xml

@@ -197,11 +197,11 @@
     <string name="sync_interval_section">Sync Interval</string>
     <string name="sync_interval_info">Determines how often the app syncs in the background. Shorter intervals mean more up-to-date data, but use slightly more battery.\n\n⏱️ Note: When your phone is in standby, Android may delay syncs (up to 60 min) to save battery. This is normal and affects all background apps.</string>
     <string name="sync_interval_15min_title">⚡ Every 15 minutes</string>
-    <string name="sync_interval_15min_subtitle">Fastest sync • ~0.8% battery/day (~23 mAh)</string>
+    <string name="sync_interval_15min_subtitle">Fastest sync • ~0.8%% battery/day (~23 mAh)</string>
     <string name="sync_interval_30min_title">✓ Every 30 minutes (Recommended)</string>
-    <string name="sync_interval_30min_subtitle">Balanced ratio • ~0.4% battery/day (~12 mAh)</string>
+    <string name="sync_interval_30min_subtitle">Balanced ratio • ~0.4%% battery/day (~12 mAh)</string>
     <string name="sync_interval_60min_title">🔋 Every 60 minutes</string>
-    <string name="sync_interval_60min_subtitle">Maximum battery life • ~0.2% battery/day (~6 mAh est.)</string>
+    <string name="sync_interval_60min_subtitle">Maximum battery life • ~0.2%% battery/day (~6 mAh est.)</string>
     <!-- Legacy -->
     <string name="auto_sync_info">ℹ️ Auto-Sync:\n\n• Checks every 30 min if server is reachable\n• Works on any WiFi connection\n• Runs in background\n• Minimal battery usage (~0.4%%/day)</string>
     
@@ -225,6 +225,11 @@
     <string name="sync_trigger_boot_title">After Device Restart</string>
     <string name="sync_trigger_boot_subtitle">Starts background sync after reboot</string>
     
+    <!-- 🆕 v1.7.0: WiFi-Only Sync -->
+    <string name="sync_wifi_only_title">WiFi-only sync</string>
+    <string name="sync_wifi_only_subtitle">Sync only when connected to WiFi. Saves mobile data and prevents long wait times.</string>
+    <string name="sync_wifi_only_hint">Sync only works when connected to WiFi</string>
+    
     <string name="sync_manual_hint">Manual sync (toolbar/pull-to-refresh) is also available.</string>
     <string name="sync_manual_hint_disabled">Sync is not available in offline mode.</string>
     
@@ -254,6 +259,20 @@
     <string name="backup_local_section">Local Backup</string>
     <string name="backup_create">💾 Create Backup</string>
     <string name="backup_restore_file">📂 Restore from File</string>
+    
+    <!-- 🔐 v1.7.0: Encryption -->
+    <string name="backup_encryption_title">Encrypt Backup</string>
+    <string name="backup_encryption_subtitle">Password-protect your backup file</string>
+    <string name="backup_encryption_password">Password</string>
+    <string name="backup_encryption_password_hint">Enter password (min. 8 characters)</string>
+    <string name="backup_encryption_confirm">Confirm Password</string>
+    <string name="backup_encryption_confirm_hint">Re-enter password</string>
+    <string name="backup_encryption_error_mismatch">Passwords don\'t match</string>
+    <string name="backup_encryption_error_too_short">Password too short (min. 8 characters)</string>
+    <string name="backup_decryption_required">🔒 Encrypted Backup</string>
+    <string name="backup_decryption_password">Enter password to decrypt</string>
+    <string name="backup_decryption_error">❌ Decryption failed. Wrong password?</string>
+    
     <string name="backup_server_section">Server Backup</string>
     <string name="backup_restore_server">☁️ Restore from Server</string>
     <string name="backup_restore_dialog_title">⚠️ Restore Backup?</string>
@@ -309,6 +328,15 @@
     <string name="language_info">ℹ️ Choose your preferred language. The app will restart to apply the change.</string>
     <string name="language_changed_restart">Language changed. Restarting…</string>
     
+    <!-- ============================= -->
+    <!-- SETTINGS - DISPLAY            -->
+    <!-- ============================= -->
+    <string name="display_settings_title">Display</string>
+    <string name="display_mode_title">Note Display Mode</string>
+    <string name="display_mode_list">📋 List View</string>
+    <string name="display_mode_grid">🎨 Grid View</string>
+    <string name="display_mode_info">Grid view shows notes in a staggered Pinterest-style layout. Small notes appear side-by-side, large notes take full width.</string>
+    
     <!-- ============================= -->
     <!-- SETTINGS - ABOUT              -->
     <!-- ============================= -->
@@ -358,6 +386,8 @@
     <string name="toast_logs_deleted">🗑️ Logs deleted</string>
     <string name="toast_no_logs_to_delete">📭 No logs to delete</string>
     <string name="toast_logs_delete_error">❌ Error deleting: %s</string>
+    <!-- 🔄 v1.7.0: Server change notification -->
+    <string name="toast_server_changed_sync_reset">🔄 Server changed. %d notes will be uploaded on next sync.</string>
     <string name="toast_link_error">❌ Error opening link</string>
     <string name="toast_file_logging_enabled">📝 File logging enabled</string>
     <string name="toast_file_logging_disabled">📝 File logging disabled</string>

android/app/src/main/res/xml/network_security_config.xml

@@ -11,6 +11,8 @@
     <base-config cleartextTrafficPermitted="true">
         <trust-anchors>
             <certificates src="system" />
+            <!-- 🔐 v1.7.0: Trust user-installed CA certificates for self-signed SSL support -->
+            <certificates src="user" />
         </trust-anchors>
     </base-config>
 </network-security-config>

android/app/src/test/java/dev/dettmer/simplenotes/models/NoteSizeTest.kt

@@ -0,0 +1,172 @@
+package dev.dettmer.simplenotes.models
+
+import dev.dettmer.simplenotes.models.NoteSize.Companion.SMALL_CHECKLIST_THRESHOLD
+import dev.dettmer.simplenotes.models.NoteSize.Companion.SMALL_TEXT_THRESHOLD
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+/**
+ * 🎨 v1.7.0: Tests for Note Size Classification (Staggered Grid Layout)
+ */
+class NoteSizeTest {
+    
+    @Test
+    fun `text note with less than 80 chars is SMALL`() {
+        val note = Note(
+            id = "test1",
+            title = "Test",
+            content = "Short content",  // 13 chars
+            deviceId = "test-device",
+            noteType = NoteType.TEXT
+        )
+        
+        assertEquals(NoteSize.SMALL, note.getSize())
+    }
+    
+    @Test
+    fun `text note with exactly 79 chars is SMALL`() {
+        val content = "x".repeat(79)  // Exactly threshold - 1
+        val note = Note(
+            id = "test2",
+            title = "Test",
+            content = content,
+            deviceId = "test-device",
+            noteType = NoteType.TEXT
+        )
+        
+        assertEquals(NoteSize.SMALL, note.getSize())
+    }
+    
+    @Test
+    fun `text note with exactly 80 chars is LARGE`() {
+        val content = "x".repeat(SMALL_TEXT_THRESHOLD)  // Exactly at threshold
+        val note = Note(
+            id = "test3",
+            title = "Test",
+            content = content,
+            deviceId = "test-device",
+            noteType = NoteType.TEXT
+        )
+        
+        assertEquals(NoteSize.LARGE, note.getSize())
+    }
+    
+    @Test
+    fun `text note with more than 80 chars is LARGE`() {
+        val content = "This is a long note with more than 80 characters. " +
+                "It should be classified as LARGE for grid layout display."
+        val note = Note(
+            id = "test4",
+            title = "Test",
+            content = content,
+            deviceId = "test-device",
+            noteType = NoteType.TEXT
+        )
+        
+        assertEquals(NoteSize.LARGE, note.getSize())
+    }
+    
+    @Test
+    fun `checklist with 1 item is SMALL`() {
+        val note = Note(
+            id = "test5",
+            title = "Shopping",
+            content = "",
+            deviceId = "test-device",
+            noteType = NoteType.CHECKLIST,
+            checklistItems = listOf(
+                ChecklistItem("id1", "Milk", false)
+            )
+        )
+        
+        assertEquals(NoteSize.SMALL, note.getSize())
+    }
+    
+    @Test
+    fun `checklist with 4 items is SMALL`() {
+        val note = Note(
+            id = "test6",
+            title = "Shopping",
+            content = "",
+            deviceId = "test-device",
+            noteType = NoteType.CHECKLIST,
+            checklistItems = listOf(
+                ChecklistItem("id1", "Milk", false),
+                ChecklistItem("id2", "Bread", false),
+                ChecklistItem("id3", "Eggs", false),
+                ChecklistItem("id4", "Butter", false)
+            )
+        )
+        
+        assertEquals(NoteSize.SMALL, note.getSize())
+    }
+    
+    @Test
+    fun `checklist with 5 items is LARGE`() {
+        val note = Note(
+            id = "test7",
+            title = "Shopping",
+            content = "",
+            deviceId = "test-device",
+            noteType = NoteType.CHECKLIST,
+            checklistItems = listOf(
+                ChecklistItem("id1", "Milk", false),
+                ChecklistItem("id2", "Bread", false),
+                ChecklistItem("id3", "Eggs", false),
+                ChecklistItem("id4", "Butter", false),
+                ChecklistItem("id5", "Cheese", false)  // 5th item -> LARGE
+            )
+        )
+        
+        assertEquals(NoteSize.LARGE, note.getSize())
+    }
+    
+    @Test
+    fun `checklist with many items is LARGE`() {
+        val items = (1..10).map { ChecklistItem("id$it", "Item $it", false) }
+        val note = Note(
+            id = "test8",
+            title = "Long List",
+            content = "",
+            deviceId = "test-device",
+            noteType = NoteType.CHECKLIST,
+            checklistItems = items
+        )
+        
+        assertEquals(NoteSize.LARGE, note.getSize())
+    }
+    
+    @Test
+    fun `empty checklist is SMALL`() {
+        val note = Note(
+            id = "test9",
+            title = "Empty",
+            content = "",
+            deviceId = "test-device",
+            noteType = NoteType.CHECKLIST,
+            checklistItems = emptyList()
+        )
+        
+        assertEquals(NoteSize.SMALL, note.getSize())
+    }
+    
+    @Test
+    fun `checklist with null items is SMALL`() {
+        val note = Note(
+            id = "test10",
+            title = "Null Items",
+            content = "",
+            deviceId = "test-device",
+            noteType = NoteType.CHECKLIST,
+            checklistItems = null
+        )
+        
+        assertEquals(NoteSize.SMALL, note.getSize())
+    }
+    
+    @Test
+    fun `constants have expected values`() {
+        assertEquals(80, SMALL_TEXT_THRESHOLD)
+        assertEquals(4, SMALL_CHECKLIST_THRESHOLD)
+    }
+}

android/app/src/test/java/dev/dettmer/simplenotes/utils/EncryptionManagerTest.kt

@@ -0,0 +1,205 @@
+package dev.dettmer.simplenotes.utils
+
+import dev.dettmer.simplenotes.backup.EncryptionException
+import dev.dettmer.simplenotes.backup.EncryptionManager
+import org.junit.Assert.*
+import org.junit.Test
+import java.security.SecureRandom
+import kotlin.text.Charsets.UTF_8
+
+/**
+ * 🔒 v1.7.0: Tests for Local Backup Encryption
+ */
+class EncryptionManagerTest {
+    
+    private val encryptionManager = EncryptionManager()
+    
+    @Test
+    fun `encrypt and decrypt roundtrip preserves data`() {
+        val originalData = "This is a test backup with UTF-8: äöü 🔒".toByteArray(UTF_8)
+        val password = "TestPassword123"
+        
+        val encrypted = encryptionManager.encrypt(originalData, password)
+        val decrypted = encryptionManager.decrypt(encrypted, password)
+        
+        assertArrayEquals(originalData, decrypted)
+    }
+    
+    @Test
+    fun `encrypted data has correct header format`() {
+        val data = "Test data".toByteArray(UTF_8)
+        val password = "password123"
+        
+        val encrypted = encryptionManager.encrypt(data, password)
+        
+        // Check magic bytes "SNE1"
+        val magic = encrypted.copyOfRange(0, 4)
+        assertArrayEquals("SNE1".toByteArray(UTF_8), magic)
+        
+        // Check version (1 byte = 0x01)
+        assertEquals(1, encrypted[4].toInt())
+        
+        // Check minimum size: magic(4) + version(1) + salt(32) + iv(12) + ciphertext + tag(16)
+        assertTrue("Encrypted data too small: ${encrypted.size}", encrypted.size >= 4 + 1 + 32 + 12 + 16)
+    }
+    
+    @Test
+    fun `isEncrypted returns true for encrypted data`() {
+        val data = "Test".toByteArray(UTF_8)
+        val encrypted = encryptionManager.encrypt(data, "password")
+        
+        assertTrue(encryptionManager.isEncrypted(encrypted))
+    }
+    
+    @Test
+    fun `isEncrypted returns false for plaintext data`() {
+        val plaintext = "This is not encrypted".toByteArray(UTF_8)
+        
+        assertFalse(encryptionManager.isEncrypted(plaintext))
+    }
+    
+    @Test
+    fun `isEncrypted returns false for short data`() {
+        val shortData = "SNE".toByteArray(UTF_8)  // Less than 4 bytes
+        
+        assertFalse(encryptionManager.isEncrypted(shortData))
+    }
+    
+    @Test
+    fun `isEncrypted returns false for wrong magic bytes`() {
+        val wrongMagic = "FAKE1234567890".toByteArray(UTF_8)
+        
+        assertFalse(encryptionManager.isEncrypted(wrongMagic))
+    }
+    
+    @Test
+    fun `decrypt with wrong password throws EncryptionException`() {
+        val data = "Sensitive data".toByteArray(UTF_8)
+        val correctPassword = "correct123"
+        val wrongPassword = "wrong123"
+        
+        val encrypted = encryptionManager.encrypt(data, correctPassword)
+        
+        val exception = assertThrows(EncryptionException::class.java) {
+            encryptionManager.decrypt(encrypted, wrongPassword)
+        }
+        
+        assertTrue(exception.message?.contains("Decryption failed") == true)
+    }
+    
+    @Test
+    fun `decrypt corrupted data throws EncryptionException`() {
+        val data = "Test".toByteArray(UTF_8)
+        val encrypted = encryptionManager.encrypt(data, "password")
+        
+        // Corrupt the ciphertext (skip header: 4 + 1 + 32 + 12 = 49 bytes)
+        val corrupted = encrypted.copyOf()
+        if (corrupted.size > 50) {
+            corrupted[50] = (corrupted[50] + 1).toByte()  // Flip one bit
+        }
+        
+        assertThrows(EncryptionException::class.java) {
+            encryptionManager.decrypt(corrupted, "password")
+        }
+    }
+    
+    @Test
+    fun `decrypt data with invalid header throws EncryptionException`() {
+        val invalidData = "This is not encrypted at all".toByteArray(UTF_8)
+        
+        assertThrows(EncryptionException::class.java) {
+            encryptionManager.decrypt(invalidData, "password")
+        }
+    }
+    
+    @Test
+    fun `decrypt truncated data throws EncryptionException`() {
+        val data = "Test".toByteArray(UTF_8)
+        val encrypted = encryptionManager.encrypt(data, "password")
+        
+        // Truncate to only header
+        val truncated = encrypted.copyOfRange(0, 20)
+        
+        assertThrows(EncryptionException::class.java) {
+            encryptionManager.decrypt(truncated, "password")
+        }
+    }
+    
+    @Test
+    fun `encrypt with different passwords produces different ciphertexts`() {
+        val data = "Same data".toByteArray(UTF_8)
+        
+        val encrypted1 = encryptionManager.encrypt(data, "password1")
+        val encrypted2 = encryptionManager.encrypt(data, "password2")
+        
+        // Different passwords should produce different ciphertexts
+        assertFalse(encrypted1.contentEquals(encrypted2))
+    }
+    
+    @Test
+    fun `encrypt same data twice produces different ciphertexts (different IV)`() {
+        val data = "Same data".toByteArray(UTF_8)
+        val password = "same-password"
+        
+        val encrypted1 = encryptionManager.encrypt(data, password)
+        val encrypted2 = encryptionManager.encrypt(data, password)
+        
+        // Different IVs should produce different ciphertexts
+        assertFalse(encrypted1.contentEquals(encrypted2))
+        
+        // But both should decrypt to same original data
+        val decrypted1 = encryptionManager.decrypt(encrypted1, password)
+        val decrypted2 = encryptionManager.decrypt(encrypted2, password)
+        assertArrayEquals(decrypted1, decrypted2)
+    }
+    
+    @Test
+    fun `encrypt large data (1MB) succeeds`() {
+        val random = SecureRandom()
+        val largeData = ByteArray(1024 * 1024)  // 1 MB
+        random.nextBytes(largeData)
+        val password = "password123"
+        
+        val encrypted = encryptionManager.encrypt(largeData, password)
+        val decrypted = encryptionManager.decrypt(encrypted, password)
+        
+        assertArrayEquals(largeData, decrypted)
+    }
+    
+    @Test
+    fun `encrypt empty data succeeds`() {
+        val emptyData = ByteArray(0)
+        val password = "password"
+        
+        val encrypted = encryptionManager.encrypt(emptyData, password)
+        val decrypted = encryptionManager.decrypt(encrypted, password)
+        
+        assertArrayEquals(emptyData, decrypted)
+    }
+    
+    @Test
+    fun `encrypt with empty password succeeds but is unsafe`() {
+        val data = "Test".toByteArray(UTF_8)
+        
+        // Crypto library accepts empty passwords (UI prevents this with validation)
+        val encrypted = encryptionManager.encrypt(data, "")
+        val decrypted = encryptionManager.decrypt(encrypted, "")
+        
+        assertArrayEquals(data, decrypted)
+        assertTrue("Empty password should still produce encrypted data", encrypted.size > data.size)
+    }
+    
+    @Test
+    fun `decrypt with unsupported version throws EncryptionException`() {
+        val data = "Test".toByteArray(UTF_8)
+        val encrypted = encryptionManager.encrypt(data, "password")
+        
+        // Change version byte to unsupported value (99)
+        val invalidVersion = encrypted.copyOf()
+        invalidVersion[4] = 99.toByte()
+        
+        assertThrows(EncryptionException::class.java) {
+            encryptionManager.decrypt(invalidVersion, "password")
+        }
+    }
+}