refactor AppTopAppBar navigation icon to use ArrowBackIosNew and update styling properties

app/src/main/java/eu/gaudian/translator/view/composable/AppTopAppBar.kt

@@ -10,11 +10,13 @@ import androidx.compose.foundation.layout.WindowInsets
 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.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.ArrowBackIosNew
 import androidx.compose.material3.CenterAlignedTopAppBar
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
-import androidx.compose.material3.IconButtonDefaults
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
@@ -94,17 +96,15 @@ fun AppTopAppBar(
             if (onNavigateBack != null) {
                 IconButton(
                     onClick = onNavigateBack,
-                    modifier = Modifier.padding(start = 8.dp),
+                    modifier = Modifier
-                    // This tells the button to paint its own circular background natively
+                        .clip(CircleShape)
-                    colors = IconButtonDefaults.iconButtonColors(
+                        .background(MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.5f))
-                        containerColor = MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.5f),
-                        contentColor = MaterialTheme.colorScheme.primary
-                    )
                 ) {
                     Icon(
-                        imageVector = AppIcons.ArrowBack,
+                        imageVector = Icons.Default.ArrowBackIosNew,
-                        contentDescription = stringResource(R.string.cd_navigate_back)
+                        contentDescription = "Back",
-                        // Notice we removed the 'tint' here, as contentColor handles it perfectly now!
+                        modifier = Modifier.size(18.dp),
+                        tint = MaterialTheme.colorScheme.primary
                     )
                 }
             } else if (navigationIcon != null) {