Card UI: Set background color

Bug: 228067197
Change-Id: I33acf1a3aabe4ca2ffe4c3ddc8646ef37873e7ad

core-ui/src/main/java/com/google/samples/apps/nowinandroid/core/ui/NewsResourceCard.kt

@@ -33,6 +33,7 @@ import androidx.compose.material.icons.filled.Bookmark
 import androidx.compose.material.icons.filled.BookmarkBorder
 import androidx.compose.material.icons.filled.Person
 import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconToggleButton
@@ -87,6 +88,7 @@ fun NewsResourceCardExpanded(
     Card(
         onClick = onClick,
         shape = RoundedCornerShape(16.dp),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surface),
         // Use custom label for accessibility services to communicate button's action to user.
         // Pass null for action to only override the label and not the actual action.
         modifier = modifier.semantics {