# React Navigation companion proposal

Proposed title: `feat(native-stack): forward iOS Stack v5 bar appearance colors`

Screens scope: add optional `backgroundColor` and `shadowColor` to the existing
`StackHeaderAppearanceIOS` type, for `standardAppearance` and
`scrollEdgeAppearance`.

The contribution guide requests a downstream PR for new public APIs. At React
Navigation main `456cda054bc636cb734e9085f70a35328cdd6a73`, native-stack still
renders the v4 `ScreenStack` and `ScreenStackItem` components. The Screens
submodule pin `449fee23ff8ebf226dad3328d711d1b95734d23b` also uses v4. Neither
has a Stack v5 header appearance object to extend or forward. These two additive
fields do not change the v4 API or current native-stack behavior.

Keep the future companion separate from the Screens PR. Once native-stack adopts
Stack v5, extend the downstream appearance option with ColorValue background and
shadow colors, forward both standard and scroll-edge objects to
`Stack.HeaderConfig`, and add an example plus option documentation. Verify
defaults, transparent/translucent and dynamic colors, independent appearances,
and removal/reset. Do not translate this into new v4 flags or migrate native-stack
as part of this concern.

Remaining gate: maintainers should confirm whether to defer the companion until
Stack v5 adoption or identify another active downstream branch that should receive
it. No downstream implementation PR was opened because there is currently no v5
consumer in native-stack main.