Set Compose TopAppBar to pure black in OLED theme

app/src/main/java/protect/card_locker/compose/Catima.kt

@@ -1,6 +1,8 @@
 package protect.card_locker.compose
 
 import androidx.activity.OnBackPressedDispatcher
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
 import androidx.compose.material3.ExperimentalMaterial3Api
@@ -8,18 +10,38 @@ import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.stringResource
 import protect.card_locker.R
+import protect.card_locker.preferences.Settings
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun CatimaTopAppBar(title: String, onBackPressedDispatcher: OnBackPressedDispatcher?) {
+    // Use pure black in OLED theme
+    val context = LocalContext.current
+    val settings = Settings(context)
+    val isDarkMode = when (settings.theme) {
+        AppCompatDelegate.MODE_NIGHT_NO -> false
+        AppCompatDelegate.MODE_NIGHT_YES -> true
+        else -> isSystemInDarkTheme()
+    }
+
+    val appBarColors = if (isDarkMode && settings.oledDark) {
+        TopAppBarDefaults.topAppBarColors().copy(containerColor = Color.Black)
+    } else {
+        TopAppBarDefaults.topAppBarColors()
+    }
+
     TopAppBar(
         modifier = Modifier.testTag("topbar_catima"),
         title = { Text(text = title) },
+        colors = appBarColors,
         navigationIcon = {
             if (onBackPressedDispatcher != null) {
                 IconButton(onClick = { onBackPressedDispatcher.onBackPressed() }) {