_layout.tsx

//app/_layout.tsx
import { Stack, router } from "expo-router";
import { Button } from "react-native";

export default function Layout() {
  return (
    <Stack>
      <Stack.Screen name="index" options={{ headerShown: false }} />
      <Stack.Screen
        name="modal"
        options={{
          presentation: "modal",
          headerLeft: () => (
            <Button title="Close" onPress={() => router.back()} />
          ),
        }}
      />
      <Stack.Screen name="(tabs)" options={{ headerShown: false }} />
    </Stack>
  );
}