diff --git a/app/src/main/java/com/example/tank/data/SettingsDataStore.kt b/app/src/main/java/com/example/tank/data/SettingsDataStore.kt
index 213dad6..6d66e1a 100644
--- a/app/src/main/java/com/example/tank/data/SettingsDataStore.kt
+++ b/app/src/main/java/com/example/tank/data/SettingsDataStore.kt
@@ -14,6 +14,7 @@ import com.google.android.gms.location.Priority
 import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlin.coroutines.resume
 
+private const val THEME_MODE = "theme_mode"
 private val Context.dataStore by preferencesDataStore(name = "settings")
 
 class SettingsDataStore(private val context: Context) {
@@ -31,6 +32,7 @@ class SettingsDataStore(private val context: Context) {
         val STATIC_LNG_KEY = doublePreferencesKey("static_lng")
         val GPS_LAT_KEY = doublePreferencesKey("gps_lat")
         val GPS_LNG_KEY = doublePreferencesKey("gps_lng")
+        val THEME_MODE_KEY = booleanPreferencesKey(THEME_MODE)
     }
 
     val selectedLocation: Flow<Pair<Double, Double>> = context.dataStore.data.map { preferences ->
@@ -178,4 +180,15 @@ class SettingsDataStore(private val context: Context) {
             }.first()
         }
     }
+
+    val isDarkTheme: Flow<Boolean> = context.dataStore.data
+        .map { preferences ->
+            preferences[PreferencesKeys.THEME_MODE_KEY] ?: false
+        }
+
+    suspend fun saveThemeMode(isDark: Boolean) {
+        context.dataStore.edit { preferences ->
+            preferences[PreferencesKeys.THEME_MODE_KEY] = isDark
+        }
+    }
 } 
\ No newline at end of file
diff --git a/app/src/main/java/com/example/tank/ui/screens/MainScreen.kt b/app/src/main/java/com/example/tank/ui/screens/MainScreen.kt
index d0b6163..478bf6f 100644
--- a/app/src/main/java/com/example/tank/ui/screens/MainScreen.kt
+++ b/app/src/main/java/com/example/tank/ui/screens/MainScreen.kt
@@ -5,6 +5,8 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Settings
+import androidx.compose.material.icons.filled.DarkMode
+import androidx.compose.material.icons.filled.LightMode
 import androidx.compose.material3.*
 import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
@@ -15,6 +17,7 @@ import androidx.navigation.compose.composable
 import androidx.navigation.compose.rememberNavController
 import com.example.tank.data.SettingsDataStore
 import com.example.tank.di.NetworkModule
+import com.example.tank.ui.theme.TankTheme
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 
@@ -53,31 +56,54 @@ fun MainScreen() {
 @Composable
 private fun MainContent() {
     val navController = rememberNavController()
+    val context = LocalContext.current
+    val settingsDataStore = remember { SettingsDataStore(context) }
+    var isDarkTheme by remember { mutableStateOf(false) }
+    val scope = rememberCoroutineScope()
     
-    Scaffold(
-        topBar = {
-            CenterAlignedTopAppBar(
-                title = { Text("Fuel Prices") },
-                actions = {
-                    IconButton(onClick = { 
-                        navController.navigate("settings") {
-                            launchSingleTop = true
-                        }
-                    }) {
-                        Icon(Icons.Default.Settings, contentDescription = "Settings")
-                    }
-                }
-            )
+    // Load saved theme preference
+    LaunchedEffect(Unit) {
+        settingsDataStore.isDarkTheme.collect { isDark ->
+            isDarkTheme = isDark
         }
-    ) { padding ->
-        NavHost(
-            navController = navController,
-            startDestination = "prices",
-            modifier = Modifier.padding(padding)
-        ) {
-            composable("prices") { PricesScreen() }
-            composable("settings") { SettingsScreen(navController = navController) }
-            composable("map") { MapScreen(navController = navController) }
+    }
+    
+    TankTheme(darkTheme = isDarkTheme) {
+        Scaffold(
+            topBar = {
+                CenterAlignedTopAppBar(
+                    title = { Text("Fuel Prices") },
+                    actions = {
+                        IconButton(onClick = { 
+                            navController.navigate("settings") {
+                                launchSingleTop = true
+                            }
+                        }) {
+                            Icon(Icons.Default.Settings, contentDescription = "Settings")
+                        }
+                    }
+                )
+            }
+        ) { padding ->
+            NavHost(
+                navController = navController,
+                startDestination = "prices",
+                modifier = Modifier.padding(padding)
+            ) {
+                composable("prices") { PricesScreen() }
+                composable("settings") { 
+                    SettingsScreen(
+                        navController = navController,
+                        isDarkTheme = isDarkTheme,
+                        onThemeChanged = { newTheme ->
+                            scope.launch {
+                                settingsDataStore.saveThemeMode(newTheme)
+                            }
+                        }
+                    )
+                }
+                composable("map") { MapScreen(navController = navController) }
+            }
         }
     }
 }
diff --git a/app/src/main/java/com/example/tank/ui/screens/PricesScreen.kt b/app/src/main/java/com/example/tank/ui/screens/PricesScreen.kt
index cc51bf7..f426272 100644
--- a/app/src/main/java/com/example/tank/ui/screens/PricesScreen.kt
+++ b/app/src/main/java/com/example/tank/ui/screens/PricesScreen.kt
@@ -551,4 +551,30 @@ private fun FavoriteStationCard(
             }
         }
     }
+}
+
+@Composable
+private fun SelectionButton(
+    text: String,
+    isSelected: Boolean,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier
+) {
+    Button(
+        onClick = onClick,
+        modifier = modifier
+            .padding(4.dp),
+        colors = ButtonDefaults.buttonColors(
+            containerColor = if (isSelected) 
+                MaterialTheme.colorScheme.primary 
+            else 
+                MaterialTheme.colorScheme.surfaceVariant,
+            contentColor = if (isSelected) 
+                MaterialTheme.colorScheme.onPrimary 
+            else 
+                MaterialTheme.colorScheme.onSurfaceVariant
+        )
+    ) {
+        Text(text)
+    }
 } 
\ No newline at end of file
diff --git a/app/src/main/java/com/example/tank/ui/screens/SettingsScreen.kt b/app/src/main/java/com/example/tank/ui/screens/SettingsScreen.kt
index 34387e9..3120fa2 100644
--- a/app/src/main/java/com/example/tank/ui/screens/SettingsScreen.kt
+++ b/app/src/main/java/com/example/tank/ui/screens/SettingsScreen.kt
@@ -30,7 +30,11 @@ import androidx.compose.foundation.rememberScrollState
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
-fun SettingsScreen(navController: NavController) {
+fun SettingsScreen(
+    navController: NavController,
+    isDarkTheme: Boolean,
+    onThemeChanged: (Boolean) -> Unit
+) {
     val context = LocalContext.current
     val settingsDataStore = remember { SettingsDataStore(context) }
     val scope = rememberCoroutineScope()
@@ -380,6 +384,26 @@ fun SettingsScreen(navController: NavController) {
             )
         }
 
+        // Add Theme Section
+        SettingsSection(title = "Appearance") {
+            Row(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(vertical = 8.dp),
+                horizontalArrangement = Arrangement.SpaceBetween,
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                Text(
+                    text = "Dark Theme",
+                    style = MaterialTheme.typography.bodyLarge
+                )
+                Switch(
+                    checked = isDarkTheme,
+                    onCheckedChange = { onThemeChanged(it) }
+                )
+            }
+        }
+
         Spacer(modifier = Modifier.height(16.dp))
 
         // Save Button