Simon Expo Header Base

3. Apply sheet rules when needed:

• For route-level sheets, configure in _layout.tsx with presentation: "formSheet".
• Set sheetGrabberVisible: true.
• Reuse Simon detents: [0.35] for compact action sheets, [0.7, 1.0] for picker/context sheets.
• Hide nested headers inside sheet routes (headerShown: false) and keep transparent content when appropriate.

4. Apply liquid-glass rules when needed:

• Use GlassView for high-emphasis surfaces only (title capsule, key cards, swipe actions).
• Prefer glassEffectStyle="regular".
• Use isInteractive for tappable glass surfaces.
• Keep capsule geometry smooth with large radius and borderCurve: "continuous" where used.

5. Verify behavior:

• Back action exists on left when screen is not root.
• Right actions are reachable in both compact and large title states.
• Search remains in bottom toolbar via Stack.Toolbar.SearchBarSlot.
• Header blur/transparency matches neighboring screens.

Placement Policy

• left: navigation (chevron.left, history).
• right: settings/info/filter/overflow menus.
• bottom or default toolbar: search slot + compose/add/switch controls.
• Stack.Toolbar.View: custom inline control area inside toolbar (for example text input mode).

Guardrails

• Do not introduce a second header system (custom absolute-position header view).
• Do not switch to opaque header backgrounds for Simon stack screens that already use transparent/blurred headers.
• Do not hardcode colors outside theme tokens when composing header/title/toolbar text.
• Do not move sheet presentation options out of stack route config unless the existing screen already uses local modal behavior.

Output Contract

When applying this skill, produce:

1. The selected pattern source file(s) from pattern-map.md.
2. The exact recipe variant used from header-recipes.md.
3. The final code adapted to the target screen with minimal divergence from Simon conventions.
4. A short checklist confirming toolbar placement, sheet behavior, and glass usage.