diff --git a/crates/openpencil-shell-core/src/event.rs b/crates/openpencil-shell-core/src/event.rs
deleted file mode 100644
index e176c3a7e..000000000
--- a/crates/openpencil-shell-core/src/event.rs
+++ /dev/null
@@ -1,226 +0,0 @@
-//! `ShellEvent` — OP widget-facing primitive event enum (spec v19 §5.1).
-//!
-//! Per spec §1.2 (FROZEN 2026-05-04) shell-core must compile on
-//! `wasm32-unknown-unknown` and remain platform-neutral on iOS / Android.
-//! This module therefore declares **only OP types** — no winit, no Jian,
-//! no GL — so the enum is visible everywhere widgets compile (mobile +
-//! WASM included). The desktop mapper that lifts Jian `PointerEvent` into
-//! `ShellEvent` lives in `openpencil-shell-native::event` (target-gated to
-//! macOS / Linux / Windows; Step 1f extends to mobile).
-//!
-//! ## Spec invariants (§11 mobile-readiness)
-//! - 6 variants: `PointerMove / PointerButton / MouseWheel / Touch / Window / Key`.
-//! - `Touch` carries `TouchForce` (`Calibrated` mirrors winit::Force 1:1
-//!   to avoid Step 1f mobile API break, plus `Normalized` for Android).
-//! - Newtype id fields are `pub` (spec round 3 BLOCK-R3-4 fix) so callers
-//!   in shell-native can construct them across crate boundaries.
-
-use crate::render_backend::Point2D;
-
-/// Stable identity for a single pointer (mouse/pen/stylus/trackpad cursor).
-///
-/// Widened to `u64` here so OP can ingest mappers from platforms (iOS, Web)
-/// whose finger ids exceed Jian's `u32` `PointerId`. Desktop mapper widens
-/// `jian_core::gesture::PointerId(u32)` → `PointerId(u64)` losslessly.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct PointerId(pub u64);
-
-/// Stable identity for a single touch/finger contact.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct TouchId(pub u64);
-
-/// Lifecycle of a touch contact (spec §5.1).
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum TouchPhase {
-    /// Finger landed.
-    Started,
-    /// Finger moved while held.
-    Moved,
-    /// Finger lifted normally.
-    Ended,
-    /// System cancelled tracking (focus loss / iOS face-proximity /
-    /// Android system-gesture intercept).
-    Cancelled,
-}
-
-/// Pressure / force for a touch contact (mirrors `winit::event::Force`
-/// 1:1 to avoid Step 1f mobile API break, per spec §11.3 invariant).
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum TouchForce {
-    /// iOS 3D Touch / Apple Pencil. `force` is the raw force value;
-    /// `max_possible_force` is the touch sensor's max; `altitude_angle`
-    /// is the Pencil tilt angle in radians (π/2 = perpendicular).
-    Calibrated {
-        force: f64,
-        max_possible_force: f64,
-        altitude_angle: Option<f64>,
-    },
-    /// Android pressure (already normalized to [0.0, 1.0]).
-    Normalized(f64),
-}
-
-/// Mouse buttons (spec §5.1; mirrors winit::event::MouseButton).
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum MouseButton {
-    Left,
-    Right,
-    Middle,
-    Back,
-    Forward,
-    Other(u16),
-}
-
-/// Pressed/released state for buttons + keys.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum ElementState {
-    Pressed,
-    Released,
-}
-
-/// Mouse wheel / two-finger trackpad scroll delta.
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum ScrollDelta {
-    /// Discrete scroll, in lines (mouse wheel notch).
-    LineDelta { x: f32, y: f32 },
-    /// Continuous scroll, in logical pixels (trackpad).
-    PixelDelta(Point2D),
-}
-
-/// Modifier-key state at the moment an event was raised.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub struct Modifiers {
-    pub shift: bool,
-    pub ctrl: bool,
-    pub alt: bool,
-    /// Cmd on macOS, Super/Win on Linux/Windows (mirrors Jian `Modifiers::CMD`).
-    pub meta: bool,
-}
-
-/// Subset of keys OP currently surfaces (spec §5.1; expanded as widgets
-/// need them in Step 1c+). Variant names follow winit::keyboard::KeyCode
-/// for easy mapping. `Other(u32)` carries the raw scancode so
-/// shell-native can pass through unmapped keys without losing them.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub enum KeyCode {
-    // Letters
-    A,
-    B,
-    C,
-    D,
-    E,
-    F,
-    G,
-    H,
-    I,
-    J,
-    K,
-    L,
-    M,
-    N,
-    O,
-    P,
-    Q,
-    R,
-    S,
-    T,
-    U,
-    V,
-    W,
-    X,
-    Y,
-    Z,
-    // Digits
-    Digit0,
-    Digit1,
-    Digit2,
-    Digit3,
-    Digit4,
-    Digit5,
-    Digit6,
-    Digit7,
-    Digit8,
-    Digit9,
-    // Whitespace / control
-    Space,
-    Enter,
-    Tab,
-    Backspace,
-    Escape,
-    Delete,
-    // Arrows
-    ArrowLeft,
-    ArrowRight,
-    ArrowUp,
-    ArrowDown,
-    // Modifiers (released as standalone keys)
-    Shift,
-    Control,
-    Alt,
-    Meta,
-    /// Anything else — raw scancode. Step 1c+ widgets that need a
-    /// specific key add a named variant.
-    Other(u32),
-}
-
-/// Window-level event kinds (spec §5.1; the desktop mapper synthesizes
-/// these directly from winit `WindowEvent`, never via Jian).
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum WindowEventKind {
-    /// Window content area resized (logical pixels via `inner_size`).
-    Resized { width: u32, height: u32 },
-    /// HiDPI scale factor changed (Retina toggle, monitor switch).
-    ScaleFactorChanged(f64),
-    /// User clicked the close button / hit Cmd-W / etc.
-    CloseRequested,
-    /// Focus gained (`true`) or lost (`false`).
-    Focused(bool),
-}
-
-/// Widget-facing primitive event (spec v19 §5.1).
-///
-/// Layered on top of Jian `PointerEvent` (which only carries
-/// pointer/touch primitives — pos/buttons-bitset/phase). Window / Key /
-/// MouseWheel events do **not** route through Jian; they come straight
-/// from winit on desktop. See [`crate::event`] module docs and spec
-/// §5.1.1 for the full mapping contract.
-#[derive(Debug, Clone, PartialEq)]
-pub enum ShellEvent {
-    /// Pointer moved (cursor or pen) — no button state change.
-    PointerMove {
-        id: PointerId,
-        pos: Point2D,
-        modifiers: Modifiers,
-    },
-    /// One pointer button transitioned Pressed/Released.
-    /// Multi-button transitions (e.g. mid-gesture press of an additional
-    /// button) are emitted as one `PointerButton` per changed bit, plus
-    /// a trailing `PointerMove` if Jian phase was `Move` — see spec
-    /// §5.1.1 for the full diff contract.
-    PointerButton {
-        id: PointerId,
-        button: MouseButton,
-        state: ElementState,
-        pos: Point2D,
-        modifiers: Modifiers,
-    },
-    /// Mouse wheel / trackpad scroll.
-    MouseWheel {
-        delta: ScrollDelta,
-        modifiers: Modifiers,
-    },
-    /// Touch contact lifecycle event (mobile-ready; Step 1f).
-    Touch {
-        id: TouchId,
-        phase: TouchPhase,
-        pos: Point2D,
-        force: Option<TouchForce>,
-    },
-    /// Window-level event (resize, scale change, close, focus).
-    Window { kind: WindowEventKind },
-    /// Keyboard event.
-    Key {
-        key: KeyCode,
-        state: ElementState,
-        modifiers: Modifiers,
-    },
-}
diff --git a/crates/openpencil-shell-core/src/lib.rs b/crates/openpencil-shell-core/src/lib.rs
index 66a881739..fe8d836e0 100644
--- a/crates/openpencil-shell-core/src/lib.rs
+++ b/crates/openpencil-shell-core/src/lib.rs
@@ -28,6 +28,18 @@ pub use render_backend::{Color, Point2D, Rect, RenderBackend, TextLayout};
 /// consistent with Jian; OP-specific differentiation is at the canvas
 /// viewport / chrome layer (single-page + infinite canvas recommended,
 /// multi-page also supported), not at event-type abstraction.
+///
+/// Step 1b §2.4 additions (P0.5A jian PR):
+/// - `KeyEvent` + supporting `KeyValue` / `NamedKey` / `KeyCode` /
+///   `KeyLocation` / `KeyState` for browser + winit keyboard input.
+/// - `ImeEvent` + `ImeKind` for IME composition (UTF-8 byte-indexed
+///   selection per spec §2.4).
+/// - `FocusEvent` for window-level / widget-level focus transitions
+///   (separate from `FocusManager`'s internal Tab-ring chain).
+/// - `WheelEvent` + `ScrollMode` for W3C `WheelEvent.deltaMode` parity
+///   on browser + native winit hosts.
 pub use jian_core::gesture::{
-    Modifiers, MouseButtons, PointerEvent, PointerId, PointerKind, PointerPhase,
+    FocusEvent, ImeEvent, ImeKind, KeyCode, KeyEvent, KeyLocation, KeyState, KeyValue, Modifiers,
+    MouseButtons, NamedKey, PointerEvent, PointerId, PointerKind, PointerPhase, ScrollMode,
+    WheelEvent,
 };
diff --git a/crates/openpencil-shell-core/tests/event_shape.rs b/crates/openpencil-shell-core/tests/event_shape.rs
deleted file mode 100644
index 3ac5f00cc..000000000
--- a/crates/openpencil-shell-core/tests/event_shape.rs
+++ /dev/null
@@ -1,92 +0,0 @@
-//! Plan v7 Task 3 Step 12 — proves the `ShellEvent` enum shape (spec
-//! §5.1) is reachable through the public re-export path and matches the
-//! 6-variant invariant. Constructed via the cross-platform OP types
-//! only — no Jian / winit / GL imports — so this test compiles on
-//! wasm32 and mobile too (verified by `cargo check
-//! --target wasm32-unknown-unknown -p openpencil-shell-core`).
-
-use openpencil_shell_core::event::{
-    ElementState, KeyCode, Modifiers, MouseButton, PointerId, ScrollDelta, ShellEvent, TouchForce,
-    TouchId, TouchPhase, WindowEventKind,
-};
-use openpencil_shell_core::render_backend::Point2D;
-
-#[test]
-fn six_variants_constructible_via_re_export() {
-    let mods = Modifiers {
-        shift: true,
-        ctrl: false,
-        alt: false,
-        meta: false,
-    };
-    let pos = Point2D::new(1.0, 2.0);
-
-    let events = [
-        ShellEvent::PointerMove {
-            id: PointerId(1),
-            pos,
-            modifiers: mods,
-        },
-        ShellEvent::PointerButton {
-            id: PointerId(1),
-            button: MouseButton::Left,
-            state: ElementState::Pressed,
-            pos,
-            modifiers: mods,
-        },
-        ShellEvent::MouseWheel {
-            delta: ScrollDelta::LineDelta { x: 0.0, y: 1.0 },
-            modifiers: mods,
-        },
-        ShellEvent::Touch {
-            id: TouchId(7),
-            phase: TouchPhase::Started,
-            pos,
-            force: Some(TouchForce::Normalized(0.5)),
-        },
-        ShellEvent::Window {
-            kind: WindowEventKind::Resized {
-                width: 800,
-                height: 600,
-            },
-        },
-        ShellEvent::Key {
-            key: KeyCode::Escape,
-            state: ElementState::Released,
-            modifiers: mods,
-        },
-    ];
-    assert_eq!(events.len(), 6, "spec §5.1 declares exactly 6 variants");
-}
-
-#[test]
-fn touch_force_calibrated_mirrors_winit() {
-    // Spec §11.3 invariant: `TouchForce::Calibrated` mirrors
-    // `winit::event::Force::Calibrated` 1:1 — fields exist with the
-    // declared names so a Step 1f mobile mapper compiles.
-    let f = TouchForce::Calibrated {
-        force: 0.4,
-        max_possible_force: 1.0,
-        altitude_angle: Some(std::f64::consts::FRAC_PI_2),
-    };
-    if let TouchForce::Calibrated {
-        force,
-        max_possible_force,
-        altitude_angle,
-    } = f
-    {
-        assert_eq!(force, 0.4);
-        assert_eq!(max_possible_force, 1.0);
-        assert_eq!(altitude_angle, Some(std::f64::consts::FRAC_PI_2));
-    } else {
-        panic!("expected Calibrated variant");
-    }
-}
-
-#[test]
-fn newtype_id_fields_pub_constructible() {
-    // Round 3 BLOCK-R3-4 fix: `TouchId(pub u64)` + `PointerId(pub u64)`
-    // constructible across crates so shell-native's mapper works.
-    let _ = TouchId(42);
-    let _ = PointerId(42);
-}
diff --git a/crates/openpencil-shell-core/tests/gesture_re_export.rs b/crates/openpencil-shell-core/tests/gesture_re_export.rs
new file mode 100644
index 000000000..fe61f751f
--- /dev/null
+++ b/crates/openpencil-shell-core/tests/gesture_re_export.rs
@@ -0,0 +1,89 @@
+use openpencil_shell_core::{
+    FocusEvent, ImeEvent, ImeKind, KeyCode, KeyEvent, KeyLocation, KeyState, KeyValue, Modifiers,
+    MouseButtons, NamedKey, PointerEvent, PointerId, PointerKind, PointerPhase, ScrollMode,
+    WheelEvent,
+};
+
+#[test]
+fn pointer_event_is_re_exported_from_jian() {
+    let event = PointerEvent::simple(
+        7,
+        PointerPhase::Down,
+        jian_core::geometry::Point::new(12.0, 34.0),
+    );
+
+    let _: PointerEvent = event.clone();
+    let _: jian_core::gesture::PointerEvent = event.clone();
+
+    assert_eq!(event.id, PointerId(7));
+    assert_eq!(event.kind, PointerKind::Touch);
+    assert_eq!(event.phase, PointerPhase::Down);
+    assert_eq!(event.position.x, 12.0);
+    assert_eq!(event.position.y, 34.0);
+    assert!(event.buttons.contains(MouseButtons::LEFT));
+    assert!(event.modifiers.is_empty());
+}
+
+#[test]
+fn pointer_modifier_and_button_flags_keep_jian_names() {
+    let mods = Modifiers::SHIFT | Modifiers::CMD;
+    assert!(mods.contains(Modifiers::SHIFT));
+    assert!(mods.contains(Modifiers::CMD));
+    assert!(!mods.contains(Modifiers::CTRL));
+
+    let buttons = MouseButtons::LEFT | MouseButtons::RIGHT;
+    assert!(buttons.contains(MouseButtons::LEFT));
+    assert!(buttons.contains(MouseButtons::RIGHT));
+    assert!(!buttons.contains(MouseButtons::MIDDLE));
+}
+
+#[test]
+fn key_event_is_re_exported_from_jian() {
+    let event = KeyEvent {
+        key: KeyValue::Named(NamedKey::Enter),
+        code: KeyCode::Enter,
+        location: KeyLocation::Standard,
+        modifiers: Modifiers::empty(),
+        state: KeyState::Pressed,
+        repeat: false,
+        is_composing: false,
+    };
+    let _: jian_core::gesture::KeyEvent = event.clone();
+    assert_eq!(event.key, KeyValue::Named(NamedKey::Enter));
+}
+
+#[test]
+fn ime_event_is_re_exported_from_jian() {
+    let event = ImeEvent {
+        kind: ImeKind::CompositionUpdate {
+            selection: Some(0..6),
+        },
+        text: "你好".to_string(),
+    };
+    let _: jian_core::gesture::ImeEvent = event.clone();
+    match event.kind {
+        ImeKind::CompositionUpdate { selection } => assert_eq!(selection, Some(0..6)),
+        _ => panic!("expected CompositionUpdate"),
+    }
+}
+
+#[test]
+fn focus_event_is_re_exported_from_jian() {
+    let event = FocusEvent {
+        gained: true,
+        node_id_hint: Some(11),
+        related_node_id_hint: Some(7),
+    };
+    let _: jian_core::gesture::FocusEvent = event;
+    assert!(event.gained);
+}
+
+#[test]
+fn wheel_event_is_re_exported_from_jian() {
+    let event = WheelEvent::simple(
+        jian_core::geometry::Point::new(0.0, 0.0),
+        jian_core::geometry::Point::new(0.0, 120.0),
+    );
+    assert_eq!(event.mode, ScrollMode::Pixel);
+    assert_eq!(event.delta_z, 0.0);
+}