feat(engine): UX iteration round — tooltip slider, streak fire, score breakdown

Three small UX improvements bundled because they share ui_theme token
edits.

Tooltip-delay slider in Settings → Gameplay
- Settings.tooltip_delay_secs (f32, #[serde(default)] = 0.5) tunable
  via "−" / "+" icon buttons next to a value readout. Range
  [TOOLTIP_DELAY_MIN_SECS, TOOLTIP_DELAY_MAX_SECS] = [0.0, 1.5] in
  TOOLTIP_DELAY_STEP_SECS (0.1) increments. "Instant" label when
  value is 0; "{n:.1} s" otherwise.
- ui_tooltip's hover-delay comparison reads from SettingsResource
  with MOTION_TOOLTIP_DELAY_SECS as the fallback when the resource
  is absent (test path). New tooltip_should_show(elapsed, delay)
  pure helper covers the boundary cases.
- adjust_tooltip_delay clamps; sanitized() carries the clamp through
  load. Five round-trip / default / legacy-deserialise tests.

Win-streak milestone fire animation
- New WinStreakMilestoneEvent { streak: u32 } fired from stats_plugin
  when win_streak_current crosses any of [3, 5, 10] (only the
  threshold crossing — not every subsequent win). HUD streak readout
  scale-pulses 1.0 → 1.20 → 1.0 over MOTION_STREAK_FLOURISH_SECS
  (0.6 s) on receipt; mirrors the foundation-flourish curve shape.
- Three threshold-crossing tests pin the firing contract.

Score-breakdown reveal on the win modal
- Win modal body replaces the single "Score: N" line with a
  per-component reveal: Base score, Time bonus (m:ss), No-undo
  bonus, Mode multiplier, separator, Total. Rows fade in over
  MOTION_SCORE_BREAKDOWN_FADE_SECS (0.12 s) staggered by
  MOTION_SCORE_BREAKDOWN_STAGGER_SECS (0.15 s) so the math reads as
  it animates. Skipped rows: zero time bonus, undo-tainted no-undo
  bonus, multiplier == 1.0.
- Honours AnimSpeed::Instant: rows spawn fully visible, no stagger.
- New ScoreBreakdown::compute helper sources base from
  GameWonEvent.score, time bonus from
  solitaire_core::scoring::compute_time_bonus, no-undo from a +25
  constant when undo_count == 0, mode multiplier from GameMode (Zen
  zeros the total). 9 new tests cover the math and the reveal
  cadence.

Test count net: +25 across the workspace (1007 → 1031).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

solitaire_data/src/lib.rs

@@ -126,7 +126,7 @@ pub use challenge::{challenge_count, challenge_seed_for, CHALLENGE_SEEDS};
 pub mod settings;
 pub use settings::{
     load_settings_from, save_settings_to, settings_file_path, AnimSpeed, Settings, SyncBackend,
-    Theme, WindowGeometry,
+    Theme, WindowGeometry, TOOLTIP_DELAY_MAX_SECS, TOOLTIP_DELAY_MIN_SECS, TOOLTIP_DELAY_STEP_SECS,
 };
 
 pub mod auth_tokens;

solitaire_data/src/settings.rs

@@ -143,6 +143,14 @@ pub struct Settings {
     /// so the toast still does not fire for them.
     #[serde(default)]
     pub shown_achievement_onboarding: bool,
+    /// Hover delay (seconds) before a tooltip appears. Range
+    /// `[0.0, 1.5]`; default matches `MOTION_TOOLTIP_DELAY_SECS` (0.5 s).
+    /// `0.0` means tooltips fire on the very next tick after hover —
+    /// the "Instant" setting. Older `settings.json` files written before
+    /// this field existed deserialize cleanly to the default via
+    /// `#[serde(default = "default_tooltip_delay")]`.
+    #[serde(default = "default_tooltip_delay")]
+    pub tooltip_delay_secs: f32,
 }
 
 fn default_draw_mode() -> DrawMode {
@@ -161,6 +169,26 @@ fn default_theme_id() -> String {
     "default".to_string()
 }
 
+/// Default tooltip-hover dwell delay in seconds. Mirrors
+/// `solitaire_engine::ui_theme::MOTION_TOOLTIP_DELAY_SECS` so legacy
+/// `settings.json` files load to the existing baseline. The constant
+/// lives in the engine crate (which the data crate cannot depend on),
+/// so the value is duplicated here — kept in sync by the
+/// `settings_tooltip_delay_default_is_existing_baseline` test in
+/// `solitaire_engine::settings_plugin`.
+fn default_tooltip_delay() -> f32 {
+    0.5
+}
+
+/// Lower bound of the player-tunable tooltip delay slider, in seconds.
+pub const TOOLTIP_DELAY_MIN_SECS: f32 = 0.0;
+
+/// Upper bound of the player-tunable tooltip delay slider, in seconds.
+pub const TOOLTIP_DELAY_MAX_SECS: f32 = 1.5;
+
+/// Increment applied by the tooltip-delay decrement / increment buttons.
+pub const TOOLTIP_DELAY_STEP_SECS: f32 = 0.1;
+
 impl Default for Settings {
     fn default() -> Self {
         Self {
@@ -177,17 +205,22 @@ impl Default for Settings {
             window_geometry: None,
             selected_theme_id: default_theme_id(),
             shown_achievement_onboarding: false,
+            tooltip_delay_secs: default_tooltip_delay(),
         }
     }
 }
 
 impl Settings {
-    /// Clamps both `sfx_volume` and `music_volume` into `[0.0, 1.0]` after
+    /// Clamps `sfx_volume`, `music_volume`, and `tooltip_delay_secs` into
-    /// deserialization or hand-editing of `settings.json`.
+    /// their respective ranges after deserialization or hand-editing of
+    /// `settings.json`.
     pub fn sanitized(self) -> Self {
         Self {
             sfx_volume: self.sfx_volume.clamp(0.0, 1.0),
             music_volume: self.music_volume.clamp(0.0, 1.0),
+            tooltip_delay_secs: self
+                .tooltip_delay_secs
+                .clamp(TOOLTIP_DELAY_MIN_SECS, TOOLTIP_DELAY_MAX_SECS),
             ..self
         }
     }
@@ -203,6 +236,15 @@ impl Settings {
         self.music_volume = (self.music_volume + delta).clamp(0.0, 1.0);
         self.music_volume
     }
+
+    /// Adjust the tooltip-hover dwell delay by `delta` seconds, clamped
+    /// to `[TOOLTIP_DELAY_MIN_SECS, TOOLTIP_DELAY_MAX_SECS]`. Returns the
+    /// new value.
+    pub fn adjust_tooltip_delay(&mut self, delta: f32) -> f32 {
+        self.tooltip_delay_secs = (self.tooltip_delay_secs + delta)
+            .clamp(TOOLTIP_DELAY_MIN_SECS, TOOLTIP_DELAY_MAX_SECS);
+        self.tooltip_delay_secs
+    }
 }
 
 /// Returns the platform-specific path to `settings.json`, or `None` if
@@ -253,6 +295,7 @@ mod tests {
         assert_eq!(s.animation_speed, AnimSpeed::Normal);
         assert_eq!(s.theme, Theme::Green);
         assert_eq!(s.sync_backend, SyncBackend::Local);
+        assert!((s.tooltip_delay_secs - default_tooltip_delay()).abs() < 1e-6);
     }
 
     #[test]
@@ -331,6 +374,7 @@ mod tests {
             window_geometry: None,
             selected_theme_id: "default".to_string(),
             shown_achievement_onboarding: false,
+            tooltip_delay_secs: default_tooltip_delay(),
         };
         save_settings_to(&path, &s).expect("save");
         let loaded = load_settings_from(&path);
@@ -563,4 +607,86 @@ mod tests {
             "legacy settings.json missing shown_achievement_onboarding must deserialize to false"
         );
     }
+
+    // -----------------------------------------------------------------------
+    // tooltip_delay_secs — player-tunable tooltip hover delay
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn settings_tooltip_delay_default_is_existing_baseline() {
+        // The existing baseline pre-slider is 0.5 s, matching the
+        // `MOTION_TOOLTIP_DELAY_SECS` constant in
+        // `solitaire_engine::ui_theme`. The default must not regress.
+        let s = Settings::default();
+        assert!(
+            (s.tooltip_delay_secs - 0.5).abs() < 1e-6,
+            "tooltip_delay_secs default must be 0.5 (the pre-slider baseline), got {}",
+            s.tooltip_delay_secs
+        );
+    }
+
+    #[test]
+    fn settings_tooltip_delay_round_trip() {
+        let path = tmp_path("tooltip_delay_round_trip");
+        let _ = fs::remove_file(&path);
+        let s = Settings {
+            tooltip_delay_secs: 1.2,
+            ..Settings::default()
+        };
+        save_settings_to(&path, &s).expect("save");
+        let loaded = load_settings_from(&path);
+        assert!(
+            (loaded.tooltip_delay_secs - 1.2).abs() < 1e-6,
+            "tooltip_delay_secs must survive serde round-trip; got {}",
+            loaded.tooltip_delay_secs
+        );
+        let _ = fs::remove_file(&path);
+    }
+
+    #[test]
+    fn legacy_settings_without_tooltip_delay_deserializes_to_default() {
+        // A settings.json written before this field existed must
+        // deserialize cleanly to the existing 0.5 s baseline rather
+        // than failing the whole load or yielding a zero value.
+        let json = br#"{ "sfx_volume": 0.7, "first_run_complete": true }"#;
+        let s: Settings = serde_json::from_slice(json).unwrap_or_default();
+        assert!(
+            (s.tooltip_delay_secs - default_tooltip_delay()).abs() < 1e-6,
+            "legacy settings.json missing tooltip_delay_secs must deserialize to default ({}), got {}",
+            default_tooltip_delay(),
+            s.tooltip_delay_secs
+        );
+    }
+
+    #[test]
+    fn adjust_tooltip_delay_clamps_to_range() {
+        let mut s = Settings { tooltip_delay_secs: 0.5, ..Default::default() };
+        // Step up to 0.6.
+        assert!((s.adjust_tooltip_delay(0.1) - 0.6).abs() < 1e-6);
+        // Big positive jump clamps to TOOLTIP_DELAY_MAX_SECS.
+        assert!((s.adjust_tooltip_delay(5.0) - TOOLTIP_DELAY_MAX_SECS).abs() < 1e-6);
+        // Big negative jump clamps to TOOLTIP_DELAY_MIN_SECS.
+        assert!((s.adjust_tooltip_delay(-99.0) - TOOLTIP_DELAY_MIN_SECS).abs() < 1e-6);
+        // Confirm the floor is exactly zero.
+        assert_eq!(s.tooltip_delay_secs, 0.0);
+    }
+
+    #[test]
+    fn sanitized_clamps_out_of_range_tooltip_delay() {
+        // Negative or oversized values from a hand-edited file must be
+        // clamped on load.
+        let s = Settings {
+            tooltip_delay_secs: -0.4,
+            ..Settings::default()
+        }
+        .sanitized();
+        assert_eq!(s.tooltip_delay_secs, TOOLTIP_DELAY_MIN_SECS);
+
+        let s2 = Settings {
+            tooltip_delay_secs: 99.0,
+            ..Settings::default()
+        }
+        .sanitized();
+        assert_eq!(s2.tooltip_delay_secs, TOOLTIP_DELAY_MAX_SECS);
+    }
 }

solitaire_engine/src/events.rs

@@ -83,6 +83,26 @@ pub struct FoundationCompletedEvent {
     pub suit: Suit,
 }
 
+/// Fired by `StatsPlugin` when the player's `win_streak_current`
+/// crosses one of the milestone thresholds in
+/// [`crate::ui_theme::STREAK_MILESTONES`] (currently 3, 5, 10).
+///
+/// Fires only on the threshold crossing — i.e. when the previous
+/// streak was below the threshold and the post-win streak is at or
+/// above it — so subsequent wins past the highest milestone do not
+/// retrigger the flourish.
+///
+/// Drives the HUD streak-milestone flourish (a brief scale pulse on
+/// the score readout) and an informational toast. UI/audio cue only;
+/// not persisted, not synchronised.
+#[derive(Message, Debug, Clone, Copy)]
+pub struct WinStreakMilestoneEvent {
+    /// The new `win_streak_current` value at the moment the
+    /// threshold was crossed. Always equal to a value in
+    /// [`crate::ui_theme::STREAK_MILESTONES`].
+    pub streak: u32,
+}
+
 /// Fired when a card's face-up state changes during gameplay.
 #[derive(Message, Debug, Clone, Copy)]
 pub struct CardFlippedEvent(pub u32);

solitaire_engine/src/hud_plugin.rs

@@ -19,16 +19,17 @@ use crate::settings_plugin::SettingsResource;
 use crate::layout::HUD_BAND_HEIGHT;
 use crate::ui_theme::{
     scaled_duration, ACCENT_PRIMARY, ACCENT_SECONDARY, BG_ELEVATED, BG_ELEVATED_HI,
-    BG_ELEVATED_PRESSED, BG_HUD_BAND, BORDER_SUBTLE, MOTION_SCORE_PULSE_SECS, RADIUS_MD, RADIUS_SM,
+    BG_ELEVATED_PRESSED, BG_HUD_BAND, BORDER_SUBTLE, MOTION_SCORE_PULSE_SECS,
-    STATE_DANGER, STATE_INFO, STATE_SUCCESS, STATE_WARNING, TEXT_PRIMARY, TEXT_SECONDARY,
+    MOTION_STREAK_FLOURISH_SECS, RADIUS_MD, RADIUS_SM, STATE_DANGER, STATE_INFO, STATE_SUCCESS,
-    TYPE_BODY, TYPE_BODY_LG, TYPE_CAPTION, TYPE_HEADLINE, VAL_SPACE_1, VAL_SPACE_2, VAL_SPACE_3,
+    STATE_WARNING, STREAK_FLOURISH_PEAK_SCALE, TEXT_PRIMARY, TEXT_SECONDARY, TYPE_BODY,
+    TYPE_BODY_LG, TYPE_CAPTION, TYPE_HEADLINE, VAL_SPACE_1, VAL_SPACE_2, VAL_SPACE_3,
 };
 use crate::events::{
     HelpRequestEvent, InfoToastEvent, NewGameRequestEvent, PauseRequestEvent,
     StartChallengeRequestEvent, StartDailyChallengeRequestEvent, StartTimeAttackRequestEvent,
     StartZenRequestEvent, ToggleAchievementsRequestEvent, ToggleLeaderboardRequestEvent,
     ToggleProfileRequestEvent, ToggleSettingsRequestEvent, ToggleStatsRequestEvent,
-    UndoRequestEvent,
+    UndoRequestEvent, WinStreakMilestoneEvent,
 };
 use crate::font_plugin::FontResource;
 use crate::game_plugin::GameMutation;
@@ -130,6 +131,51 @@ pub struct ScoreFloater {
     pub duration: f32,
 }
 
+/// Drives the streak-milestone flourish: scales the [`HudScore`] text
+/// from `1.0 → STREAK_FLOURISH_PEAK_SCALE → 1.0` over
+/// [`MOTION_STREAK_FLOURISH_SECS`] (scaled by
+/// [`AnimSpeed`](solitaire_data::AnimSpeed)) and tints it
+/// [`ACCENT_SECONDARY`] for the same window before restoring the
+/// original colour.
+///
+/// The streak readout currently lives in the Stats overlay (press
+/// `S`) — there is no always-on HUD streak counter — so the flourish
+/// piggybacks on the score readout, which is the most prominent
+/// always-visible HUD number. Mirrors the `FoundationFlourish`
+/// pattern: triangular scale curve, fixed duration, restores state
+/// when the timer expires.
+///
+/// Inserted on `HudScore` entities by `start_streak_flourish` when a
+/// `WinStreakMilestoneEvent` fires; removed once `elapsed >=
+/// duration` so the readout returns to its rest state for the next
+/// frame's transform sync.
+///
+/// Coexists with [`ScorePulse`]: the streak flourish lives on a
+/// dedicated marker so a streak-crossing win that also ticks the
+/// score (every win does) doesn't have the two animations stomp on
+/// each other's `Transform.scale` writes — the streak flourish runs
+/// in a `Without<ScorePulse>` query so only the loudest of the two
+/// celebrations is active at a time.
+#[derive(Component, Debug, Clone, Copy)]
+pub struct StreakFlourish {
+    /// The streak milestone that triggered this flourish (3, 5, 10).
+    /// Carried for diagnostic logging only — the visual is identical
+    /// for every threshold so play-testing can decide later whether
+    /// to differentiate.
+    pub streak: u32,
+    /// Seconds elapsed since the flourish began.
+    pub elapsed: f32,
+    /// Total animation length in seconds. Zero under
+    /// [`AnimSpeed::Instant`](solitaire_data::AnimSpeed) — the system
+    /// snaps the scale back to 1.0 on the first tick so no half-state
+    /// is ever shown.
+    pub duration: f32,
+    /// The score readout's colour before the flourish began —
+    /// restored when the timer expires so the readout returns to its
+    /// resting `TEXT_PRIMARY` (or whatever it was) tint.
+    pub original_color: Color,
+}
+
 /// Tracks the score from the previous frame so the HUD can detect
 /// changes without a `ScoreChangedEvent`. The plugin wires this to the
 /// pulse + floater systems on every `Update`.
@@ -251,6 +297,7 @@ impl Plugin for HudPlugin {
             .add_message::<ToggleProfileRequestEvent>()
             .add_message::<ToggleSettingsRequestEvent>()
             .add_message::<ToggleLeaderboardRequestEvent>()
+            .add_message::<WinStreakMilestoneEvent>()
             .init_resource::<PreviousScore>()
             .init_resource::<HudActionFade>()
             .add_systems(Startup, (spawn_hud_band, spawn_hud, spawn_action_buttons))
@@ -267,6 +314,12 @@ impl Plugin for HudPlugin {
                     .chain()
                     .after(GameMutation),
             )
+            .add_systems(
+                Update,
+                (start_streak_flourish, advance_streak_flourish)
+                    .chain()
+                    .after(GameMutation),
+            )
             .add_systems(
                 Update,
                 (
@@ -1285,6 +1338,148 @@ fn advance_score_floater(
     }
 }
 
+// ---------------------------------------------------------------------------
+// Streak-milestone flourish
+//
+// Per the 2026-04-30 UX overhaul plan, the foundation flourish is the per-suit
+// completion celebration; the streak flourish is its lifetime equivalent —
+// when the player's `win_streak_current` crosses 3, 5, or 10, the HUD score
+// readout pulses larger than a normal score-change pulse and tints magenta
+// (`ACCENT_SECONDARY`) before snapping back to its resting state.
+//
+// Why the score readout: there is no always-on streak number on the HUD
+// today (the readout lives in the Stats overlay), and the score is the
+// most prominent always-visible HUD figure. The accompanying `InfoToastEvent`
+// fired by `stats_plugin` carries the explicit "Win streak: N!" text so a
+// player who isn't watching the score still sees the celebration land.
+// ---------------------------------------------------------------------------
+
+/// Pure helper for unit tests — returns the per-frame scale factor for
+/// the streak flourish at `elapsed_secs` over `duration_secs`.
+///
+/// Triangular curve, mirroring [`foundation_flourish_scale`](crate::feedback_anim_plugin::foundation_flourish_scale):
+/// at `t = 0.0` returns `1.0`, at `t = 0.5` returns
+/// [`STREAK_FLOURISH_PEAK_SCALE`], at `t = 1.0` returns `1.0`.
+/// Out-of-range values are clamped so the score readout never freezes
+/// at a non-1.0 scale on the frame after the flourish ends.
+///
+/// Returns `1.0` whenever `duration_secs <= 0.0` so callers running
+/// under `AnimSpeed::Instant` (zeroed durations) skip the flourish
+/// without dividing by zero.
+pub fn streak_flourish_scale(elapsed_secs: f32, duration_secs: f32) -> f32 {
+    if duration_secs <= 0.0 {
+        return 1.0;
+    }
+    let t = (elapsed_secs / duration_secs).clamp(0.0, 1.0);
+    let peak = STREAK_FLOURISH_PEAK_SCALE;
+    if t < 0.5 {
+        // Climb from 1.0 at t=0 to peak at t=0.5.
+        1.0 + (peak - 1.0) * (t / 0.5)
+    } else {
+        // Descend from peak at t=0.5 back to 1.0 at t=1.0.
+        peak - (peak - 1.0) * ((t - 0.5) / 0.5)
+    }
+}
+
+/// Inserts a [`StreakFlourish`] on every [`HudScore`] entity when a
+/// [`WinStreakMilestoneEvent`] fires. Captures the readout's current
+/// `TextColor` so `advance_streak_flourish` can restore it when the
+/// timer expires; reuses any existing flourish's `original_color` so
+/// re-entering the system mid-flourish doesn't snapshot the magenta
+/// tint as the new "original".
+///
+/// Removes any concurrent [`ScorePulse`] from the same entity so the
+/// flourish takes over the scale slot cleanly — score pulses last
+/// 250 ms, the flourish 600 ms, and the streak crossing always
+/// coincides with a positive score delta, so the flourish is the
+/// louder of the two celebrations.
+fn start_streak_flourish(
+    mut events: MessageReader<WinStreakMilestoneEvent>,
+    settings: Option<Res<SettingsResource>>,
+    score_q: Query<(Entity, &TextColor, Option<&StreakFlourish>), With<HudScore>>,
+    mut commands: Commands,
+) {
+    let Some(latest) = events.read().last() else {
+        return;
+    };
+    let speed = settings
+        .as_ref()
+        .map(|s| s.0.animation_speed)
+        .unwrap_or_default();
+    let duration = scaled_duration(MOTION_STREAK_FLOURISH_SECS, speed);
+    for (entity, color, existing) in &score_q {
+        let original_color = existing.map_or(color.0, |f| f.original_color);
+        commands
+            .entity(entity)
+            .remove::<ScorePulse>()
+            .insert(StreakFlourish {
+                streak: latest.streak,
+                elapsed: 0.0,
+                duration,
+                original_color,
+            });
+    }
+}
+
+/// Advances every [`StreakFlourish`], scaling its entity's `Transform`
+/// using [`streak_flourish_scale`] and lerping the `TextColor` toward
+/// [`ACCENT_SECONDARY`] for the first half then back to the captured
+/// `original_color`. Removes the component once `elapsed >= duration`
+/// (or immediately under [`AnimSpeed::Instant`](solitaire_data::AnimSpeed)
+/// where duration is 0) and pins the scale back to 1.0 / restores the
+/// original colour so no half-state is ever shown.
+///
+/// Filtered with `Without<ScorePulse>` so the streak flourish never
+/// races a score pulse for the same `Transform.scale` slot —
+/// `start_streak_flourish` strips any concurrent `ScorePulse` from the
+/// score entity before this system runs, so the filter is purely a
+/// belt-and-braces invariant.
+fn advance_streak_flourish(
+    time: Res<Time>,
+    mut commands: Commands,
+    mut q: Query<
+        (Entity, &mut StreakFlourish, &mut Transform, &mut TextColor),
+        Without<ScorePulse>,
+    >,
+) {
+    let dt = time.delta_secs();
+    for (entity, mut anim, mut transform, mut color) in &mut q {
+        let t = if anim.duration <= 0.0 {
+            1.0
+        } else {
+            anim.elapsed += dt;
+            (anim.elapsed / anim.duration).clamp(0.0, 1.0)
+        };
+        let scale = streak_flourish_scale(anim.elapsed, anim.duration);
+        transform.scale = Vec3::new(scale, scale, 1.0);
+        // Tint mix: full magenta at t=0..=0.5, fades back to the
+        // original colour over t=0.5..=1.0.
+        let mix = if t < 0.5 { 1.0 } else { 1.0 - (t - 0.5) / 0.5 };
+        color.0 = lerp_text_color(anim.original_color, ACCENT_SECONDARY, mix);
+        if t >= 1.0 {
+            transform.scale = Vec3::ONE;
+            color.0 = anim.original_color;
+            commands.entity(entity).remove::<StreakFlourish>();
+        }
+    }
+}
+
+/// sRGB-space linear interpolation between two `Color`s — small local
+/// helper so `advance_streak_flourish` stays readable. sRGB-space
+/// lerping is fine for a brief decorative tint (a perceptually-uniform
+/// space would be overkill).
+fn lerp_text_color(from: Color, to: Color, t: f32) -> Color {
+    let from = from.to_srgba();
+    let to = to.to_srgba();
+    let t = t.clamp(0.0, 1.0);
+    Color::srgba(
+        from.red + (to.red - from.red) * t,
+        from.green + (to.green - from.green) * t,
+        from.blue + (to.blue - from.blue) * t,
+        from.alpha + (to.alpha - from.alpha) * t,
+    )
+}
+
 #[allow(clippy::type_complexity, clippy::too_many_arguments)]
 fn update_hud(
     game: Res<GameStateResource>,
@@ -2091,6 +2286,45 @@ mod tests {
         assert!((score_pulse_scale(2.0) - 1.0).abs() < 1e-6);
     }
 
+    /// Streak flourish curve must be 1.0 at t=0, peak at t=0.5, and
+    /// return to 1.0 at t=duration. Mirrors the `foundation_flourish_scale`
+    /// curve test — the two animations share a triangular shape so a
+    /// future tweak that desyncs them shows up here.
+    #[test]
+    fn streak_flourish_scale_curves_through_one_one_one() {
+        let dur = MOTION_STREAK_FLOURISH_SECS;
+        assert!(
+            (streak_flourish_scale(0.0, dur) - 1.0).abs() < 1e-5,
+            "streak flourish scale at t=0 must be 1.0",
+        );
+        assert!(
+            (streak_flourish_scale(dur / 2.0, dur) - STREAK_FLOURISH_PEAK_SCALE).abs() < 1e-5,
+            "streak flourish scale at midpoint must be STREAK_FLOURISH_PEAK_SCALE",
+        );
+        assert!(
+            (streak_flourish_scale(dur, dur) - 1.0).abs() < 1e-5,
+            "streak flourish scale at t=duration must return to 1.0",
+        );
+    }
+
+    /// Out-of-range values are clamped, not extrapolated. Matches the
+    /// foundation flourish's clamp behaviour so the score readout never
+    /// freezes at a non-1.0 scale on the frame after the flourish ends.
+    #[test]
+    fn streak_flourish_scale_clamps_out_of_range() {
+        let dur = MOTION_STREAK_FLOURISH_SECS;
+        assert!((streak_flourish_scale(-1.0, dur) - 1.0).abs() < 1e-5);
+        assert!((streak_flourish_scale(dur * 5.0, dur) - 1.0).abs() < 1e-5);
+    }
+
+    /// Zero duration (e.g. `AnimSpeed::Instant`) returns identity, never
+    /// divides by zero.
+    #[test]
+    fn streak_flourish_scale_zero_duration_is_one() {
+        assert!((streak_flourish_scale(0.0, 0.0) - 1.0).abs() < 1e-5);
+        assert!((streak_flourish_scale(0.5, 0.0) - 1.0).abs() < 1e-5);
+    }
+
     // -----------------------------------------------------------------------
     // Phase 2: keyboard focus ring — HUD action bar
     // -----------------------------------------------------------------------

solitaire_engine/src/lib.rs

@@ -89,14 +89,15 @@ pub use events::{
     StartDailyChallengeRequestEvent, StartTimeAttackRequestEvent, StartZenRequestEvent,
     StateChangedEvent, SyncCompleteEvent, ToggleAchievementsRequestEvent,
     ToggleLeaderboardRequestEvent, ToggleProfileRequestEvent, ToggleSettingsRequestEvent,
-    ToggleStatsRequestEvent, UndoRequestEvent, XpAwardedEvent,
+    ToggleStatsRequestEvent, UndoRequestEvent, WinStreakMilestoneEvent, XpAwardedEvent,
 };
 pub use game_plugin::{ConfirmNewGameScreen, GameMutation, GameOverScreen, GamePlugin, GameStatePath};
 pub use help_plugin::{HelpPlugin, HelpScreen};
 pub use home_plugin::{HomePlugin, HomeScreen};
 pub use hud_plugin::{
-    ActionButton, HelpButton, HudAutoComplete, HudPlugin, MenuButton, MenuOption, MenuPopover,
+    streak_flourish_scale, ActionButton, HelpButton, HudAutoComplete, HudPlugin, MenuButton,
-    ModeOption, ModesButton, ModesPopover, NewGameButton, PauseButton, UndoButton,
+    MenuOption, MenuPopover, ModeOption, ModesButton, ModesPopover, NewGameButton, PauseButton,
+    StreakFlourish, UndoButton,
 };
 pub use leaderboard_plugin::{LeaderboardPlugin, LeaderboardResource, LeaderboardScreen};
 pub use input_plugin::InputPlugin;

solitaire_engine/src/settings_plugin.rs

@@ -18,7 +18,7 @@ use bevy::window::{WindowMoved, WindowResized};
 use solitaire_core::game_state::DrawMode;
 use solitaire_data::{
     load_settings_from, save_settings_to, settings_file_path, settings::Theme, AnimSpeed, Settings,
-    WindowGeometry,
+    WindowGeometry, TOOLTIP_DELAY_STEP_SECS,
 };
 
 use crate::events::{ManualSyncRequestEvent, ToggleSettingsRequestEvent};
@@ -122,6 +122,10 @@ struct BackgroundText;
 #[derive(Component, Debug)]
 struct ColorBlindText;
 
+/// Marks the `Text` node showing the live tooltip-delay value.
+#[derive(Component, Debug)]
+struct TooltipDelayText;
+
 /// Marks the scrollable inner card so the mouse-wheel system can target it.
 #[derive(Component, Debug)]
 struct SettingsPanelScrollable;
@@ -139,6 +143,10 @@ enum SettingsButton {
     MusicUp,
     ToggleDrawMode,
     CycleAnimSpeed,
+    /// Decrement the tooltip-hover dwell delay by one step.
+    TooltipDelayDown,
+    /// Increment the tooltip-hover dwell delay by one step.
+    TooltipDelayUp,
     ToggleTheme,
     ToggleColorBlind,
     SyncNow,
@@ -169,6 +177,8 @@ impl SettingsButton {
             // Gameplay section
             SettingsButton::ToggleDrawMode => 30,
             SettingsButton::CycleAnimSpeed => 40,
+            SettingsButton::TooltipDelayDown => 45,
+            SettingsButton::TooltipDelayUp => 46,
             // Cosmetic section
             SettingsButton::ToggleTheme => 50,
             SettingsButton::ToggleColorBlind => 60,
@@ -258,6 +268,7 @@ impl Plugin for SettingsPlugin {
                     update_background_text,
                     update_anim_speed_text,
                     update_color_blind_text,
+                    update_tooltip_delay_text,
                     attach_focusable_to_settings_buttons,
                     scroll_focus_into_view,
                 ),
@@ -483,6 +494,21 @@ fn update_color_blind_text(
     }
 }
 
+/// Refreshes the live tooltip-delay value in the Gameplay section
+/// whenever `SettingsResource` changes (slider buttons, hand-edited
+/// settings.json reload, etc.).
+fn update_tooltip_delay_text(
+    settings: Res<SettingsResource>,
+    mut text_nodes: Query<&mut Text, With<TooltipDelayText>>,
+) {
+    if !settings.is_changed() {
+        return;
+    }
+    for mut text in &mut text_nodes {
+        **text = tooltip_delay_label(settings.0.tooltip_delay_secs);
+    }
+}
+
 fn card_back_label(idx: usize) -> String {
     if idx == 0 {
         "Default".to_string()
@@ -606,6 +632,24 @@ fn handle_settings_buttons(
                     **t = anim_speed_label(&settings.0.animation_speed);
                 }
             }
+            SettingsButton::TooltipDelayDown => {
+                let before = settings.0.tooltip_delay_secs;
+                let after = settings.0.adjust_tooltip_delay(-TOOLTIP_DELAY_STEP_SECS);
+                if (before - after).abs() > f32::EPSILON {
+                    persist(&path, &settings.0);
+                    changed.write(SettingsChangedEvent(settings.0.clone()));
+                    // The Text node is refreshed by `update_tooltip_delay_text`
+                    // on the next frame via `settings.is_changed()`.
+                }
+            }
+            SettingsButton::TooltipDelayUp => {
+                let before = settings.0.tooltip_delay_secs;
+                let after = settings.0.adjust_tooltip_delay(TOOLTIP_DELAY_STEP_SECS);
+                if (before - after).abs() > f32::EPSILON {
+                    persist(&path, &settings.0);
+                    changed.write(SettingsChangedEvent(settings.0.clone()));
+                }
+            }
             SettingsButton::ToggleTheme => {
                 settings.0.theme = match settings.0.theme {
                     Theme::Green => Theme::Blue,
@@ -680,6 +724,17 @@ fn color_blind_label(enabled: bool) -> String {
     if enabled { "ON".into() } else { "OFF".into() }
 }
 
+/// Formats the tooltip-hover delay for display in the Settings panel.
+/// `0.0` reads as `"Instant"` so the zero-delay case has a name; any
+/// other value prints as `"{n:.1} s"` (e.g. `"0.5 s"`, `"1.2 s"`).
+fn tooltip_delay_label(secs: f32) -> String {
+    if secs <= 0.0 {
+        "Instant".into()
+    } else {
+        format!("{secs:.1} s")
+    }
+}
+
 /// Auto-attaches [`Focusable`] to every bespoke Settings button — icon
 /// buttons (volume +/−, toggle, cycle), swatch buttons (card-back,
 /// background pickers), and the "Sync Now" button. The "Done" button is
@@ -1003,6 +1058,11 @@ fn spawn_settings_panel(
                 "Cycle animation speed: Normal, Fast, Instant.",
                 font_res,
             );
+            tooltip_delay_row(
+                body,
+                settings.tooltip_delay_secs,
+                font_res,
+            );
 
             // --- Cosmetic ---
             section_label(body, "Cosmetic", font_res);
@@ -1129,6 +1189,53 @@ fn volume_row<Marker: Component>(
         });
 }
 
+/// `Tooltip Delay  0.5 s  [−]  [+]` — slider row for the player-tunable
+/// tooltip-hover dwell. Mirrors [`volume_row`] (label, current value,
+/// decrement, increment) but formats the value via [`tooltip_delay_label`]
+/// so `0.0` reads as `"Instant"` and other values as `"{n:.1} s"`.
+fn tooltip_delay_row(
+    parent: &mut ChildSpawnerCommands,
+    value_secs: f32,
+    font_res: Option<&FontResource>,
+) {
+    let label_font = label_text_font(font_res);
+    let value_font = value_text_font(font_res);
+    parent
+        .spawn(Node {
+            flex_direction: FlexDirection::Row,
+            align_items: AlignItems::Center,
+            column_gap: VAL_SPACE_2,
+            ..default()
+        })
+        .with_children(|row| {
+            row.spawn((
+                Text::new("Tooltip Delay".to_string()),
+                label_font,
+                TextColor(TEXT_SECONDARY),
+            ));
+            row.spawn((
+                TooltipDelayText,
+                Text::new(tooltip_delay_label(value_secs)),
+                value_font,
+                TextColor(TEXT_PRIMARY),
+            ));
+            icon_button(
+                row,
+                "−",
+                SettingsButton::TooltipDelayDown,
+                "Shorten the hover delay before tooltips appear.",
+                font_res,
+            );
+            icon_button(
+                row,
+                "+",
+                SettingsButton::TooltipDelayUp,
+                "Lengthen the hover delay before tooltips appear.",
+                font_res,
+            );
+        });
+}
+
 /// `Label  Value  [⇄]` — used for cycle/toggle rows (draw mode, theme,
 /// anim speed, colour-blind).
 ///

solitaire_engine/src/stats_plugin.rs

@@ -19,6 +19,7 @@ use crate::auto_complete_plugin::AutoCompleteState;
 use crate::challenge_plugin::challenge_progress_label;
 use crate::events::{
     ForfeitEvent, GameWonEvent, InfoToastEvent, NewGameRequestEvent, ToggleStatsRequestEvent,
+    WinStreakMilestoneEvent,
 };
 use crate::game_plugin::GameMutation;
 use crate::progress_plugin::ProgressResource;
@@ -29,9 +30,9 @@ use crate::ui_modal::{
     spawn_modal, spawn_modal_actions, spawn_modal_button, spawn_modal_header, ButtonVariant,
 };
 use crate::ui_theme::{
-    ACCENT_PRIMARY, BORDER_SUBTLE, RADIUS_SM, STATE_INFO, STATE_WARNING, TEXT_PRIMARY,
+    ACCENT_PRIMARY, BORDER_SUBTLE, RADIUS_SM, STATE_INFO, STATE_WARNING, STREAK_MILESTONES,
-    TEXT_SECONDARY, TYPE_BODY, TYPE_BODY_LG, TYPE_CAPTION, TYPE_HEADLINE, VAL_SPACE_2, VAL_SPACE_3,
+    TEXT_PRIMARY, TEXT_SECONDARY, TYPE_BODY, TYPE_BODY_LG, TYPE_CAPTION, TYPE_HEADLINE, VAL_SPACE_2,
-    VAL_SPACE_4, Z_MODAL_PANEL,
+    VAL_SPACE_3, VAL_SPACE_4, Z_MODAL_PANEL,
 };
 
 /// Bevy resource wrapping the current stats.
@@ -93,6 +94,7 @@ impl Plugin for StatsPlugin {
             .add_message::<ForfeitEvent>()
             .add_message::<InfoToastEvent>()
             .add_message::<ToggleStatsRequestEvent>()
+            .add_message::<WinStreakMilestoneEvent>()
             // record_abandoned must read `move_count` BEFORE handle_new_game
             // clobbers it with a fresh game. These are NOT in StatsUpdate because
             // StatsUpdate (as a set) is ordered after GameMutation by external
@@ -130,15 +132,55 @@ fn update_stats_on_win(
     game: Res<GameStateResource>,
     mut stats: ResMut<StatsResource>,
     path: Res<StatsStoragePath>,
+    mut milestone: MessageWriter<WinStreakMilestoneEvent>,
+    mut toast: MessageWriter<InfoToastEvent>,
 ) {
     for ev in events.read() {
+        let prev_streak = stats.0.win_streak_current;
         stats
             .0
             .update_on_win(ev.score, ev.time_seconds, &game.0.draw_mode);
+        let new_streak = stats.0.win_streak_current;
+        // Fire the streak-milestone event only on the threshold
+        // crossing — `prev < threshold && new >= threshold`. This
+        // guarantees the flourish never retriggers at every win past
+        // the highest milestone.
+        if let Some(crossed) = streak_milestone_crossed(prev_streak, new_streak) {
+            milestone.write(WinStreakMilestoneEvent { streak: crossed });
+            toast.write(InfoToastEvent(format!(
+                "Win streak: {crossed}! \u{1F525}"
+            )));
+        }
         persist(&path, &stats.0, "win");
     }
 }
 
+/// Returns the milestone value that the player just crossed, if any.
+///
+/// A milestone is "crossed" when `prev < threshold && new >= threshold`
+/// for some `threshold` in [`STREAK_MILESTONES`]. Returns the largest
+/// such threshold (so a single win that vaults the player from a
+/// streak of 0 directly to 5 — implausible, but defensive — fires the
+/// most-celebrated milestone, not the smallest).
+///
+/// Returns `None` when no threshold was crossed, i.e. either:
+/// - the streak did not change,
+/// - the streak rose but stayed below every threshold, or
+/// - the streak rose past a threshold that `prev` was already at or
+///   above.
+///
+/// Pure function exposed for unit testing without Bevy.
+pub fn streak_milestone_crossed(prev: u32, new: u32) -> Option<u32> {
+    if new <= prev {
+        return None;
+    }
+    STREAK_MILESTONES
+        .iter()
+        .copied()
+        .filter(|&t| prev < t && new >= t)
+        .max()
+}
+
 fn update_stats_on_new_game(
     mut events: MessageReader<NewGameRequestEvent>,
     game: Res<GameStateResource>,
@@ -895,4 +937,120 @@ mod tests {
             "expected no streak-broken toast for streak of 1, got: {messages:?}"
         );
     }
+
+    // -----------------------------------------------------------------------
+    // Streak-milestone flourish — pure helper + event-firing tests
+    // -----------------------------------------------------------------------
+
+    /// Pure helper: every threshold in `STREAK_MILESTONES` (3, 5, 10) must
+    /// fire when the streak crosses it from below.
+    #[test]
+    fn streak_milestone_helper_fires_at_each_threshold() {
+        for &threshold in STREAK_MILESTONES {
+            assert_eq!(
+                streak_milestone_crossed(threshold - 1, threshold),
+                Some(threshold),
+                "expected milestone {threshold} to fire when crossed from below",
+            );
+        }
+    }
+
+    /// Pure helper: rising past 10 to 11, 12, … must NOT fire — the
+    /// flourish is a threshold-crossing event, not a "every win past 10"
+    /// event.
+    #[test]
+    fn streak_milestone_helper_does_not_fire_past_highest() {
+        // prev=10 → new=11: above the highest threshold, no crossing.
+        assert_eq!(streak_milestone_crossed(10, 11), None);
+        // prev=15 → new=16: well past every threshold, no crossing.
+        assert_eq!(streak_milestone_crossed(15, 16), None);
+        // prev=2 → new=2: no change → no crossing.
+        assert_eq!(streak_milestone_crossed(2, 2), None);
+    }
+
+    /// Pure helper: rising 1 → 2 stays below the lowest threshold (3),
+    /// must NOT fire.
+    #[test]
+    fn streak_milestone_helper_does_not_fire_below_threshold() {
+        assert_eq!(streak_milestone_crossed(1, 2), None);
+        assert_eq!(streak_milestone_crossed(0, 1), None);
+    }
+
+    /// Integration: pre-set streak to 2, fire a win that bumps it to 3,
+    /// assert exactly one `WinStreakMilestoneEvent { streak: 3 }` is
+    /// written by the win handler.
+    #[test]
+    fn streak_milestone_event_fires_at_threshold_crossing() {
+        let mut app = headless_app();
+        {
+            let mut stats = app.world_mut().resource_mut::<StatsResource>();
+            stats.0.win_streak_current = 2;
+        }
+        app.world_mut().write_message(GameWonEvent {
+            score: 500,
+            time_seconds: 90,
+        });
+        app.update();
+
+        let events = app.world().resource::<Messages<WinStreakMilestoneEvent>>();
+        let mut reader = events.get_cursor();
+        let collected: Vec<u32> = reader.read(events).map(|e| e.streak).collect();
+
+        assert_eq!(
+            collected,
+            vec![3],
+            "expected one WinStreakMilestoneEvent {{ streak: 3 }} after crossing 2 → 3",
+        );
+    }
+
+    /// Integration: pre-set streak to 1, fire a win that bumps it to 2 —
+    /// no threshold is crossed, no event must be fired.
+    #[test]
+    fn streak_milestone_event_does_not_fire_at_non_threshold() {
+        let mut app = headless_app();
+        {
+            let mut stats = app.world_mut().resource_mut::<StatsResource>();
+            stats.0.win_streak_current = 1;
+        }
+        app.world_mut().write_message(GameWonEvent {
+            score: 500,
+            time_seconds: 90,
+        });
+        app.update();
+
+        let events = app.world().resource::<Messages<WinStreakMilestoneEvent>>();
+        let mut reader = events.get_cursor();
+        let collected: Vec<u32> = reader.read(events).map(|e| e.streak).collect();
+
+        assert!(
+            collected.is_empty(),
+            "expected no WinStreakMilestoneEvent for non-threshold streak crossing 1 → 2, got {collected:?}",
+        );
+    }
+
+    /// Integration: pre-set streak to 10, fire a win that bumps it to 11.
+    /// Past the highest threshold, no event must fire — the flourish
+    /// is reserved for the threshold crossing itself.
+    #[test]
+    fn streak_milestone_event_does_not_fire_past_10() {
+        let mut app = headless_app();
+        {
+            let mut stats = app.world_mut().resource_mut::<StatsResource>();
+            stats.0.win_streak_current = 10;
+        }
+        app.world_mut().write_message(GameWonEvent {
+            score: 500,
+            time_seconds: 90,
+        });
+        app.update();
+
+        let events = app.world().resource::<Messages<WinStreakMilestoneEvent>>();
+        let mut reader = events.get_cursor();
+        let collected: Vec<u32> = reader.read(events).map(|e| e.streak).collect();
+
+        assert!(
+            collected.is_empty(),
+            "expected no WinStreakMilestoneEvent past the highest threshold, got {collected:?}",
+        );
+    }
 }

solitaire_engine/src/ui_theme.rs

@@ -361,6 +361,14 @@ pub const MOTION_CASCADE_STAGGER_SECS: f32 = 0.06;
 /// (overshoot) plus ±15° Z-rotation. 500 ms.
 pub const MOTION_CASCADE_SLIDE_SECS: f32 = 0.50;
 
+/// Per-line stagger between score-breakdown rows during the win modal
+/// reveal animation, in seconds.
+pub const MOTION_SCORE_BREAKDOWN_STAGGER_SECS: f32 = 0.15;
+
+/// Per-line fade-in duration during the win modal score reveal, in
+/// seconds.
+pub const MOTION_SCORE_BREAKDOWN_FADE_SECS: f32 = 0.12;
+
 /// Screen shake on win — wider and longer than the old 0.6 s / 8 px.
 /// 800 ms.
 pub const MOTION_WIN_SHAKE_SECS: f32 = 0.80;
@@ -395,6 +403,23 @@ pub const MOTION_FOUNDATION_FLOURISH_SECS: f32 = 0.4;
 /// 1.0 at `t=0` to this value at `t=0.5` and back to 1.0 at `t=1.0`.
 pub const FOUNDATION_FLOURISH_PEAK_SCALE: f32 = 1.15;
 
+/// Total duration of the streak-milestone flourish on the HUD score
+/// readout, in seconds. Mirrors the foundation flourish in feel — a
+/// brief celebratory pulse that does not block subsequent gameplay.
+pub const MOTION_STREAK_FLOURISH_SECS: f32 = 0.6;
+
+/// Peak scale magnification reached at the midpoint of the streak
+/// flourish (1.0 → this → 1.0). Larger than the foundation flourish
+/// peak so the lifetime-streak celebration reads as a bigger deal than
+/// the per-suit completion.
+pub const STREAK_FLOURISH_PEAK_SCALE: f32 = 1.20;
+
+/// Win-streak counts that trigger the flourish. The flourish fires
+/// only when the streak crosses a threshold from below — never at
+/// every win past the highest threshold. Static for now; could become
+/// a `Settings`-tunable list later if play-testing surfaces it.
+pub const STREAK_MILESTONES: &[u32] = &[3, 5, 10];
+
 /// Loading-ellipsis cycle — `.`/`..`/`...` toggles every step.
 /// 400 ms.
 pub const MOTION_LOADING_TICK_SECS: f32 = 0.40;

solitaire_engine/src/ui_tooltip.rs

@@ -34,6 +34,7 @@ use bevy::prelude::*;
 use bevy::ui::{ComputedNode, UiGlobalTransform};
 
 use crate::font_plugin::FontResource;
+use crate::settings_plugin::SettingsResource;
 use crate::ui_theme::{
     BG_ELEVATED_HI, BORDER_SUBTLE, MOTION_TOOLTIP_DELAY_SECS, RADIUS_SM, TEXT_PRIMARY,
     TYPE_CAPTION, VAL_SPACE_2, Z_TOOLTIP,
@@ -137,6 +138,23 @@ struct TooltipText;
 /// target's own border.
 const TOOLTIP_GAP_PX: f32 = 4.0;
 
+/// Pure helper: returns `true` once `elapsed_secs` has met or exceeded
+/// the player-configured `delay_secs`, so the tooltip should be revealed.
+///
+/// Treating "elapsed >= delay" as the show condition (rather than
+/// strictly greater than) is what makes a `delay_secs == 0.0` setting
+/// behave as advertised: on the very first tick after hover starts,
+/// `elapsed_secs` is `0.0` and the tooltip appears immediately. With a
+/// strict `>` the zero-delay case would still wait one tick.
+///
+/// Extracted so the comparison can be unit-tested without spinning up
+/// a Bevy `App` — `Time<Virtual>` clamps each tick to 250 ms under
+/// `MinimalPlugins`, which makes precise sub-second timing assertions
+/// awkward.
+pub(crate) fn tooltip_should_show(elapsed_secs: f32, delay_secs: f32) -> bool {
+    elapsed_secs >= delay_secs
+}
+
 // ---------------------------------------------------------------------------
 // Systems
 // ---------------------------------------------------------------------------
@@ -257,6 +275,7 @@ fn track_tooltip_hover(
 fn show_or_hide_tooltip(
     time: Res<Time>,
     state: Res<TooltipState>,
+    settings: Option<Res<SettingsResource>>,
     tooltips: Query<(&Tooltip, &UiGlobalTransform, &ComputedNode)>,
     tooltip_text_only: Query<&Tooltip>,
     mut overlay_q: Query<(&mut Node, &mut Visibility, &Children), With<TooltipOverlay>>,
@@ -280,9 +299,15 @@ fn show_or_hide_tooltip(
         return;
     };
 
+    // Player-configurable dwell delay; falls back to the design-token
+    // default when `SettingsResource` is absent (test harnesses running
+    // `UiTooltipPlugin` under `MinimalPlugins` without `SettingsPlugin`).
+    let delay_secs = settings
+        .as_ref()
+        .map(|s| s.0.tooltip_delay_secs)
+        .unwrap_or(MOTION_TOOLTIP_DELAY_SECS);
     let elapsed = time.elapsed().saturating_sub(started_at);
-    let delay = Duration::from_secs_f32(MOTION_TOOLTIP_DELAY_SECS);
+    if !tooltip_should_show(elapsed.as_secs_f32(), delay_secs) {
-    if elapsed < delay {
         hide(&mut visibility);
         return;
     }
@@ -550,4 +575,30 @@ mod tests {
             "overlay text must update to the new hovered entity's Tooltip string"
         );
     }
+
+    /// Test 5: `tooltip_should_show` is the pure helper that the system
+    /// uses to gate the reveal — exercising it directly avoids the
+    /// `Time<Virtual>` 250 ms clamp that makes precise sub-second
+    /// timing assertions in `MinimalPlugins` fiddly. The four cases
+    /// below cover the boundary semantics:
+    ///
+    /// * `delay = 0.0` ("Instant") must show on the first tick.
+    /// * `elapsed < delay` must NOT show.
+    /// * `elapsed == delay` must show (boundary inclusive).
+    /// * `elapsed > delay` must show.
+    #[test]
+    fn tooltip_should_show_respects_delay() {
+        // delay == 0 ("Instant"): any elapsed (including zero) shows.
+        assert!(tooltip_should_show(0.0, 0.0), "instant delay must show on first tick");
+        assert!(tooltip_should_show(0.5, 0.0));
+
+        // Standard non-zero delay.
+        assert!(!tooltip_should_show(0.4, 0.5), "elapsed < delay must hide");
+        assert!(tooltip_should_show(0.5, 0.5), "elapsed == delay must show (boundary)");
+        assert!(tooltip_should_show(0.6, 0.5), "elapsed > delay must show");
+
+        // Larger delay (max-end of the slider).
+        assert!(!tooltip_should_show(1.0, 1.5));
+        assert!(tooltip_should_show(1.5, 1.5));
+    }
 }

solitaire_engine/src/win_summary_plugin.rs

@@ -12,6 +12,8 @@
 
 use bevy::prelude::*;
 use solitaire_core::game_state::GameMode;
+use solitaire_core::scoring::compute_time_bonus;
+use solitaire_data::AnimSpeed;
 
 use crate::achievement_plugin::display_name_for;
 use crate::events::{
@@ -23,10 +25,11 @@ use crate::resources::GameStateResource;
 use crate::settings_plugin::SettingsResource;
 use crate::stats_plugin::{StatsResource, StatsUpdate};
 use crate::ui_theme::{
-    scaled_duration, ACCENT_PRIMARY, BG_BASE, BG_ELEVATED, MOTION_WIN_SHAKE_AMPLITUDE,
+    scaled_duration, ACCENT_PRIMARY, BG_BASE, BG_ELEVATED, MOTION_SCORE_BREAKDOWN_FADE_SECS,
-    MOTION_WIN_SHAKE_SECS, RADIUS_LG, RADIUS_MD, SCRIM, STATE_INFO, STATE_SUCCESS, STATE_WARNING,
+    MOTION_SCORE_BREAKDOWN_STAGGER_SECS, MOTION_WIN_SHAKE_AMPLITUDE, MOTION_WIN_SHAKE_SECS,
-    TEXT_PRIMARY, TEXT_SECONDARY, TYPE_BODY_LG, TYPE_DISPLAY, TYPE_HEADLINE, VAL_SPACE_2,
+    RADIUS_LG, RADIUS_MD, SCRIM, STATE_INFO, STATE_SUCCESS, STATE_WARNING, TEXT_PRIMARY,
-    VAL_SPACE_3, Z_WIN_CASCADE,
+    TEXT_SECONDARY, TYPE_BODY, TYPE_BODY_LG, TYPE_DISPLAY, TYPE_HEADLINE, VAL_SPACE_2, VAL_SPACE_3,
+    Z_WIN_CASCADE,
 };
 
 // ---------------------------------------------------------------------------
@@ -73,6 +76,15 @@ pub struct WinSummaryPending {
     /// human-readable level number that was just completed (e.g. `Some(3)`
     /// means "Challenge 3"). `None` for non-Challenge modes.
     pub challenge_level: Option<u32>,
+    /// Number of undos used during the winning game. Captured from
+    /// `GameStateResource` at the moment `GameWonEvent` fires so the
+    /// score-breakdown reveal can decide whether to award the no-undo
+    /// bonus row.
+    pub undo_count: u32,
+    /// Game mode of the winning game. Captured at win time so the
+    /// score-breakdown reveal can format the mode-multiplier row
+    /// (e.g. `Zen ×0.0`, `Classic ×1.0`).
+    pub mode: GameMode,
 }
 
 /// Builds a human-readable XP breakdown string for the win modal.
@@ -161,6 +173,37 @@ enum WinSummaryButton {
     PlayAgain,
 }
 
+/// Marker for one row of the win-modal score-breakdown reveal.
+///
+/// Each row carries a stagger delay (seconds until the row should
+/// become visible) plus a fade-in timer that lerps the row's text
+/// alpha from `0.0 → 1.0` over [`MOTION_SCORE_BREAKDOWN_FADE_SECS`].
+/// Rows are spawned with `Visibility::Hidden`; the reveal system
+/// flips them to `Visibility::Inherited` once `delay_secs` elapses
+/// and then drives the per-text alpha lerp until the row reaches
+/// full opacity.
+///
+/// When `AnimSpeed::Instant` is active the row is spawned with
+/// `delay_secs = 0.0`, `fade_duration_secs = 0.0`, and visibility
+/// already set to `Inherited` so the reveal happens on frame 1.
+#[derive(Component, Debug, Clone, Copy)]
+pub struct ScoreBreakdownRow {
+    /// Seconds remaining until this row first becomes visible.
+    /// Counts down to 0 in `reveal_score_breakdown`. Zero or negative
+    /// means "show immediately".
+    pub delay_secs: f32,
+    /// Seconds elapsed since this row became visible. Drives the
+    /// alpha lerp on the row's child `Text` nodes.
+    pub fade_elapsed_secs: f32,
+    /// Total fade-in duration. Zero means "no fade — appear at full
+    /// opacity in one frame".
+    pub fade_duration_secs: f32,
+    /// `true` once the row's `Visibility` has been promoted from
+    /// `Hidden` to `Inherited`. Prevents re-running the visibility
+    /// switch every frame after the row first reveals.
+    pub revealed: bool,
+}
+
 // ---------------------------------------------------------------------------
 // Plugin
 // ---------------------------------------------------------------------------
@@ -193,6 +236,7 @@ impl Plugin for WinSummaryPlugin {
                     spawn_win_summary_after_delay,
                     handle_win_summary_buttons,
                     apply_screen_shake,
+                    reveal_score_breakdown,
                 )
                     .after(GameMutation),
             );
@@ -217,6 +261,144 @@ pub fn format_win_time(seconds: u64) -> String {
     format!("{m}:{s:02}")
 }
 
+/// Score amount awarded as a "no-undo" bonus in the win modal when the
+/// player completes the game without using undo. Mirrors the XP-side
+/// no-undo bonus so the score and XP breakdowns reinforce each other,
+/// and stays a `pub const` so tests can assert against it without
+/// re-typing the literal.
+pub const SCORE_NO_UNDO_BONUS: i32 = 25;
+
+/// Decomposed view of the player's final score, displayed in the win
+/// modal as a sequence of fade-in rows.
+///
+/// The fields mirror the row layout described in the win-modal
+/// reveal:
+///
+/// ```text
+/// Base score                   {base}
+/// Time bonus ({m:ss})         +{time_bonus}
+/// No-undo bonus               +{no_undo_bonus}
+/// Mode multiplier ({mode} ×N) ×{multiplier}
+/// ─────────────────────────────────
+/// Total                        {total}
+/// ```
+///
+/// Components that do not apply to the current win are zeroed out:
+/// `time_bonus = 0` when the player took longer than the time-bonus
+/// curve produces a positive result, `no_undo_bonus = 0` when undo
+/// was used, and `multiplier = 1.0` outside Zen mode. The renderer
+/// uses these zero markers to skip rows the player would not benefit
+/// from seeing.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct ScoreBreakdown {
+    /// Running game score before the win-time bonuses are applied.
+    /// Equal to `pending.score`, which is `GameState::score` at the
+    /// moment of `GameWonEvent`.
+    pub base: i32,
+    /// Time-bonus component — `compute_time_bonus(time_seconds)`.
+    /// Zero when `time_seconds == 0` or when the formula yields zero.
+    pub time_bonus: i32,
+    /// Score awarded for completing the win without using undo.
+    /// Zero when `undo_count > 0`.
+    pub no_undo_bonus: i32,
+    /// Multiplier applied to `(base + time_bonus + no_undo_bonus)` to
+    /// produce the final total. `0.0` for Zen mode (which never
+    /// scores), `1.0` otherwise.
+    pub multiplier: f32,
+    /// Game mode the win occurred in. Used by the renderer to format
+    /// the multiplier row label, e.g. `"Mode multiplier (Zen ×0)"`.
+    pub mode: GameMode,
+    /// Elapsed game time in seconds, used to format the time-bonus
+    /// row label as `m:ss`.
+    pub time_seconds: u64,
+}
+
+impl ScoreBreakdown {
+    /// Builds a breakdown for the given win.
+    ///
+    /// `base` is the running game score (`pending.score`); `time_seconds`,
+    /// `undo_count`, and `mode` come from the captured `WinSummaryPending`.
+    /// All score arithmetic is saturating to keep the breakdown safe even
+    /// for pathologically high scores.
+    pub fn compute(base: i32, time_seconds: u64, undo_count: u32, mode: GameMode) -> Self {
+        let time_bonus = compute_time_bonus(time_seconds);
+        let no_undo_bonus = if undo_count == 0 { SCORE_NO_UNDO_BONUS } else { 0 };
+        let multiplier = match mode {
+            GameMode::Zen => 0.0,
+            GameMode::Classic | GameMode::Challenge | GameMode::TimeAttack => 1.0,
+        };
+        Self {
+            base,
+            time_bonus,
+            no_undo_bonus,
+            multiplier,
+            mode,
+            time_seconds,
+        }
+    }
+
+    /// Final total displayed on the breakdown's bottom row, rounded
+    /// half-to-even (Rust's default `as i32` cast truncates toward
+    /// zero, which is fine for a non-fractional multiplier set).
+    pub fn total(&self) -> i32 {
+        let pre_mult = self
+            .base
+            .saturating_add(self.time_bonus)
+            .saturating_add(self.no_undo_bonus);
+        ((pre_mult as f32) * self.multiplier) as i32
+    }
+
+    /// Whether the no-undo bonus row should be rendered. Skipped when
+    /// the player used undo (bonus is zero) so the modal does not
+    /// show a "+0" line that adds nothing.
+    pub fn shows_no_undo_row(&self) -> bool {
+        self.no_undo_bonus > 0
+    }
+
+    /// Whether the time-bonus row should be rendered. Skipped when
+    /// the bonus is zero (e.g. `time_seconds == 0`).
+    pub fn shows_time_bonus_row(&self) -> bool {
+        self.time_bonus > 0
+    }
+
+    /// Whether the mode-multiplier row should be rendered. Skipped
+    /// for `multiplier == 1.0` so Classic/Challenge/TimeAttack wins
+    /// do not show a redundant "×1.0" line.
+    pub fn shows_multiplier_row(&self) -> bool {
+        (self.multiplier - 1.0).abs() > f32::EPSILON
+    }
+
+    /// Total number of rows the breakdown will spawn, counting the
+    /// always-present `Base score` and `Total` rows plus the
+    /// separator. Used by tests to assert spawn counts deterministically.
+    pub fn row_count(&self) -> usize {
+        let mut n = 1; // base
+        if self.shows_time_bonus_row() {
+            n += 1;
+        }
+        if self.shows_no_undo_row() {
+            n += 1;
+        }
+        if self.shows_multiplier_row() {
+            n += 1;
+        }
+        n += 1; // separator
+        n += 1; // total
+        n
+    }
+}
+
+/// Human-readable display name for a game mode. Used as the prefix in
+/// the mode-multiplier row, e.g. `"Mode multiplier (Zen ×0)"`.
+fn mode_display_name(mode: GameMode) -> &'static str {
+    match mode {
+        GameMode::Classic => "Classic",
+        GameMode::Zen => "Zen",
+        GameMode::Challenge => "Challenge",
+        GameMode::TimeAttack => "Time Attack",
+    }
+}
+
 // ---------------------------------------------------------------------------
 // Systems
 // ---------------------------------------------------------------------------
@@ -267,6 +449,8 @@ fn cache_win_data(
         pending.xp_detail = build_xp_detail(ev.time_seconds, used_undo);
         pending.new_record = is_new_record;
         pending.challenge_level = challenge_level;
+        pending.undo_count = game.0.undo_count;
+        pending.mode = game.0.mode;
 
         if is_new_record {
             toast.write(InfoToastEvent("New Record!".to_string()));
@@ -365,7 +549,12 @@ fn spawn_win_summary_after_delay(
                     pending.xp = pending.xp.saturating_add(ev.amount);
                 }
                 let challenge_level = pending.challenge_level;
-                spawn_overlay(&mut commands, &pending, &session, challenge_level);
+                // Re-derive AnimSpeed here — the `speed` binding above
+                // only lives inside the `for _ in won.read()` loop.
+                let anim_speed = settings
+                    .as_ref()
+                    .map_or(AnimSpeed::Normal, |s| s.0.animation_speed);
+                spawn_overlay(&mut commands, &pending, &session, challenge_level, anim_speed);
             }
         }
     }
@@ -439,12 +628,25 @@ fn apply_screen_shake(
 ///
 /// `challenge_level` is `Some(N)` when the win was a Challenge-mode completion;
 /// a "Challenge N complete!" annotation is added to the modal header in that case.
+///
+/// `anim_speed` controls the score-breakdown reveal: under
+/// `AnimSpeed::Instant`, every breakdown row is spawned visible and at
+/// full opacity (no stagger, no fade); otherwise rows are spawned
+/// hidden and the [`reveal_score_breakdown`] system fades them in over
+/// roughly one second.
 fn spawn_overlay(
     commands: &mut Commands,
     pending: &WinSummaryPending,
     session: &SessionAchievements,
     challenge_level: Option<u32>,
+    anim_speed: AnimSpeed,
 ) {
+    let breakdown = ScoreBreakdown::compute(
+        pending.score,
+        pending.time_seconds,
+        pending.undo_count,
+        pending.mode,
+    );
     commands
         .spawn((
             WinSummaryOverlay,
@@ -502,12 +704,9 @@ fn spawn_overlay(
                     ));
                 }
 
-                // Score
+                // Score breakdown reveal — replaces the previous single
-                card.spawn((
+                // "Score:" line with a per-component multi-row layout.
-                    Text::new(format!("Score: {}", pending.score)),
+                spawn_score_breakdown(card, &breakdown, anim_speed);
-                    TextFont { font_size: TYPE_HEADLINE, ..default() },
-                    TextColor(TEXT_PRIMARY),
-                ));
 
                 // Time
                 card.spawn((
@@ -597,6 +796,220 @@ fn spawn_achievements_section(card: &mut ChildSpawnerCommands, names: &[String])
     }
 }
 
+/// Spawns the score-breakdown rows inside the win-modal card.
+///
+/// Rows are appended in this order — only the first and last two are
+/// always present, the middle three depend on `breakdown`:
+///
+/// 1. `Base score` — value column = `breakdown.base`.
+/// 2. `Time bonus (m:ss)` — only when `breakdown.shows_time_bonus_row()`.
+/// 3. `No-undo bonus` — only when `breakdown.shows_no_undo_row()`.
+/// 4. `Mode multiplier (Mode-name ×N)` — only when
+///    `breakdown.shows_multiplier_row()`.
+/// 5. Separator (em-dashes).
+/// 6. `Total` — value column = `breakdown.total()`.
+///
+/// Every row is spawned with a [`ScoreBreakdownRow`] component carrying
+/// a per-row stagger delay calculated from
+/// [`MOTION_SCORE_BREAKDOWN_STAGGER_SECS`]. Under `AnimSpeed::Instant`,
+/// stagger and fade are both zero so the breakdown appears in one frame.
+fn spawn_score_breakdown(
+    card: &mut ChildSpawnerCommands,
+    breakdown: &ScoreBreakdown,
+    anim_speed: AnimSpeed,
+) {
+    let stagger = scaled_duration(MOTION_SCORE_BREAKDOWN_STAGGER_SECS, anim_speed);
+    let fade = scaled_duration(MOTION_SCORE_BREAKDOWN_FADE_SECS, anim_speed);
+    let mut row_index: u32 = 0;
+
+    // 1. Base score — always shown.
+    spawn_breakdown_row(
+        card,
+        "Base score",
+        format!("{}", breakdown.base),
+        ACCENT_PRIMARY,
+        anim_speed,
+        stagger * row_index as f32,
+        fade,
+    );
+    row_index += 1;
+
+    // 2. Time bonus.
+    if breakdown.shows_time_bonus_row() {
+        spawn_breakdown_row(
+            card,
+            &format!("Time bonus ({})", format_win_time(breakdown.time_seconds)),
+            format!("+{}", breakdown.time_bonus),
+            STATE_SUCCESS,
+            anim_speed,
+            stagger * row_index as f32,
+            fade,
+        );
+        row_index += 1;
+    }
+
+    // 3. No-undo bonus.
+    if breakdown.shows_no_undo_row() {
+        spawn_breakdown_row(
+            card,
+            "No-undo bonus",
+            format!("+{}", breakdown.no_undo_bonus),
+            STATE_SUCCESS,
+            anim_speed,
+            stagger * row_index as f32,
+            fade,
+        );
+        row_index += 1;
+    }
+
+    // 4. Mode multiplier (only when not 1.0).
+    if breakdown.shows_multiplier_row() {
+        let mode_name = mode_display_name(breakdown.mode);
+        spawn_breakdown_row(
+            card,
+            &format!("Mode multiplier ({mode_name} ×{:.1})", breakdown.multiplier),
+            format!("×{:.1}", breakdown.multiplier),
+            STATE_INFO,
+            anim_speed,
+            stagger * row_index as f32,
+            fade,
+        );
+        row_index += 1;
+    }
+
+    // 5. Separator — em-dashes spanning the visual width.
+    spawn_breakdown_row(
+        card,
+        "─────────────────",
+        "─────".to_string(),
+        TEXT_SECONDARY,
+        anim_speed,
+        stagger * row_index as f32,
+        fade,
+    );
+    row_index += 1;
+
+    // 6. Total — emphasised in primary accent.
+    spawn_breakdown_row(
+        card,
+        "Total",
+        format!("{}", breakdown.total()),
+        ACCENT_PRIMARY,
+        anim_speed,
+        stagger * row_index as f32,
+        fade,
+    );
+}
+
+/// Spawns one row of the score breakdown — a flex-row `Node` with two
+/// `Text` children (label left, value right). The row is tagged with
+/// [`ScoreBreakdownRow`] and starts hidden when `anim_speed` is anything
+/// other than [`AnimSpeed::Instant`]; the [`reveal_score_breakdown`]
+/// system flips it visible after `delay_secs` and fades in the text
+/// over `fade_duration_secs`.
+fn spawn_breakdown_row(
+    card: &mut ChildSpawnerCommands,
+    label: &str,
+    value: String,
+    value_color: Color,
+    anim_speed: AnimSpeed,
+    delay_secs: f32,
+    fade_duration_secs: f32,
+) {
+    // Under Instant, every row is visible immediately at full opacity.
+    let instant = matches!(anim_speed, AnimSpeed::Instant);
+    let initial_visibility = if instant {
+        Visibility::Inherited
+    } else {
+        Visibility::Hidden
+    };
+    let initial_alpha = if instant { 1.0 } else { 0.0 };
+
+    let label_color_with_alpha = TEXT_PRIMARY.with_alpha(initial_alpha);
+    let value_color_with_alpha = value_color.with_alpha(initial_alpha);
+
+    card.spawn((
+        ScoreBreakdownRow {
+            delay_secs,
+            fade_elapsed_secs: 0.0,
+            fade_duration_secs,
+            revealed: instant,
+        },
+        Node {
+            width: Val::Percent(100.0),
+            min_width: Val::Px(280.0),
+            flex_direction: FlexDirection::Row,
+            justify_content: JustifyContent::SpaceBetween,
+            align_items: AlignItems::Center,
+            ..default()
+        },
+        initial_visibility,
+    ))
+    .with_children(|row| {
+        // Label — left-aligned.
+        row.spawn((
+            Text::new(label.to_string()),
+            TextFont { font_size: TYPE_BODY, ..default() },
+            TextColor(label_color_with_alpha),
+        ));
+        // Value — right-aligned via the parent's JustifyContent::SpaceBetween.
+        row.spawn((
+            Text::new(value),
+            TextFont { font_size: TYPE_BODY, ..default() },
+            TextColor(value_color_with_alpha),
+        ));
+    });
+}
+
+/// Reveal system — ticks each [`ScoreBreakdownRow`] down toward zero
+/// and fades its child `Text` alpha from 0 → 1 over the row's
+/// `fade_duration_secs` once `delay_secs` elapses.
+///
+/// The system is non-blocking: the Play Again button is interactable
+/// from the moment the modal spawns; the breakdown reveal just plays
+/// out underneath. Rows that have already reached full opacity are
+/// skipped via the `revealed` flag plus an early
+/// `fade_elapsed >= fade_duration` short-circuit on the alpha lerp.
+pub fn reveal_score_breakdown(
+    time: Res<Time>,
+    mut rows: Query<(&mut ScoreBreakdownRow, &mut Visibility, Option<&Children>)>,
+    mut texts: Query<&mut TextColor>,
+) {
+    let dt = time.delta_secs();
+    for (mut row, mut visibility, children) in &mut rows {
+        if !row.revealed {
+            row.delay_secs -= dt;
+            if row.delay_secs <= 0.0 {
+                *visibility = Visibility::Inherited;
+                row.revealed = true;
+            } else {
+                continue; // still hidden, no fade work yet
+            }
+        }
+        // Row is revealed — drive the fade-in until it's fully opaque.
+        let fade_done = row.fade_elapsed_secs >= row.fade_duration_secs;
+        if !fade_done {
+            row.fade_elapsed_secs += dt;
+        }
+        let t = if row.fade_duration_secs <= 0.0 {
+            1.0
+        } else {
+            (row.fade_elapsed_secs / row.fade_duration_secs).clamp(0.0, 1.0)
+        };
+        let target_alpha = if fade_done { 1.0 } else { t };
+        if let Some(children) = children {
+            for child in children.iter() {
+                if let Ok(mut tc) = texts.get_mut(child) {
+                    let c = tc.0;
+                    if (c.alpha() - target_alpha).abs() > f32::EPSILON {
+                        tc.0 = c.with_alpha(target_alpha);
+                    }
+                }
+            }
+        }
+    }
+}
+
 // ---------------------------------------------------------------------------
 // Tests
 // ---------------------------------------------------------------------------
@@ -662,6 +1075,8 @@ mod tests {
         assert!(p.xp_detail.is_empty());
         assert!(!p.new_record);
         assert!(p.challenge_level.is_none());
+        assert_eq!(p.undo_count, 0);
+        assert_eq!(p.mode, GameMode::Classic);
     }
 
     #[test]
@@ -941,4 +1356,208 @@ mod tests {
             "challenge_level must be None for non-Challenge wins"
         );
     }
+
+    // -----------------------------------------------------------------------
+    // Score-breakdown tests
+    // -----------------------------------------------------------------------
+
+    /// `cache_win_data` captures both `undo_count` and `mode` from the
+    /// `GameStateResource` at the moment of `GameWonEvent`. The breakdown
+    /// reveal needs both fields to format the no-undo-bonus and
+    /// mode-multiplier rows.
+    #[test]
+    fn cache_win_data_captures_undo_count_and_mode() {
+        use solitaire_core::game_state::DrawMode;
+
+        let mut app = make_app();
+        // Set up a Zen-mode game with 2 undos used.
+        {
+            let mut game = app.world_mut().resource_mut::<GameStateResource>();
+            game.0 = GameState::new_with_mode(7, DrawMode::DrawOne, GameMode::Zen);
+            game.0.undo_count = 2;
+        }
+
+        app.world_mut()
+            .write_message(GameWonEvent { score: 0, time_seconds: 0 });
+        app.update();
+
+        let pending = app.world().resource::<WinSummaryPending>();
+        assert_eq!(pending.undo_count, 2);
+        assert_eq!(pending.mode, GameMode::Zen);
+    }
+
+    /// `ScoreBreakdown::compute` produces the expected per-component
+    /// values for a non-trivial Classic-mode win. Time-bonus is the
+    /// canonical `compute_time_bonus(120) = 5833` (700_000 / 120) and
+    /// the no-undo bonus fires because `undo_count == 0`.
+    #[test]
+    fn score_breakdown_compute_produces_expected_components() {
+        let bd = ScoreBreakdown::compute(3200, 120, 0, GameMode::Classic);
+        assert_eq!(bd.base, 3200);
+        assert_eq!(bd.time_bonus, 5833); // 700_000 / 120
+        assert_eq!(bd.no_undo_bonus, SCORE_NO_UNDO_BONUS);
+        assert!((bd.multiplier - 1.0).abs() < f32::EPSILON);
+        // Classic ×1.0 → multiplier row is suppressed.
+        assert!(!bd.shows_multiplier_row());
+        // Total == base + time_bonus + no_undo_bonus.
+        assert_eq!(bd.total(), 3200 + 5833 + SCORE_NO_UNDO_BONUS);
+    }
+
+    /// Zen-mode wins produce a zero multiplier — the breakdown shows
+    /// the multiplier row and the total collapses to zero regardless
+    /// of the other components.
+    #[test]
+    fn score_breakdown_zen_mode_zeros_total() {
+        let bd = ScoreBreakdown::compute(500, 60, 0, GameMode::Zen);
+        assert!((bd.multiplier - 0.0).abs() < f32::EPSILON);
+        assert!(bd.shows_multiplier_row(), "Zen ×0 must display the multiplier row");
+        assert_eq!(bd.total(), 0);
+    }
+
+    /// When the player used undo, the `no_undo_bonus` is zero and the
+    /// row is suppressed.
+    #[test]
+    fn score_breakdown_skips_no_undo_row_when_undo_was_used() {
+        let bd = ScoreBreakdown::compute(100, 60, 1, GameMode::Classic);
+        assert_eq!(bd.no_undo_bonus, 0);
+        assert!(!bd.shows_no_undo_row());
+    }
+
+    /// At `time_seconds == 0` the time-bonus formula yields 0; the row
+    /// is suppressed.
+    #[test]
+    fn score_breakdown_skips_time_bonus_row_when_zero() {
+        let bd = ScoreBreakdown::compute(100, 0, 0, GameMode::Classic);
+        assert_eq!(bd.time_bonus, 0);
+        assert!(!bd.shows_time_bonus_row());
+    }
+
+    /// `row_count()` reports the number of rows the renderer will
+    /// spawn. A non-trivial Classic win with both bonuses produces:
+    /// base + time + no-undo + separator + total = 5 rows (no
+    /// multiplier row, ×1.0 is suppressed).
+    #[test]
+    fn win_modal_score_breakdown_spawns_one_row_per_component() {
+        let bd = ScoreBreakdown::compute(3200, 120, 0, GameMode::Classic);
+        assert_eq!(
+            bd.row_count(),
+            5,
+            "Classic with both bonuses: base + time + no-undo + sep + total"
+        );
+
+        // Zen with both bonuses ALSO shows the multiplier row.
+        let zen = ScoreBreakdown::compute(3200, 120, 0, GameMode::Zen);
+        assert_eq!(
+            zen.row_count(),
+            6,
+            "Zen with both bonuses: base + time + no-undo + multiplier + sep + total"
+        );
+    }
+
+    /// When `no_undo_bonus == 0`, the row count drops by one.
+    #[test]
+    fn win_modal_score_breakdown_skips_zero_bonus_rows() {
+        let bd_with = ScoreBreakdown::compute(3200, 120, 0, GameMode::Classic);
+        let bd_without = ScoreBreakdown::compute(3200, 120, 1, GameMode::Classic);
+        assert_eq!(
+            bd_with.row_count() - 1,
+            bd_without.row_count(),
+            "removing the no-undo bonus must remove exactly one row"
+        );
+    }
+
+    /// Pure helper test: the reveal logic uses delta-time to count
+    /// down `delay_secs`; at `t = 0` only the first row is "revealed",
+    /// and after one stagger interval the second row reveals as well.
+    /// We exercise the system directly on a hand-built world rather
+    /// than going through the full modal-spawn path so the test is
+    /// independent of `Time` resource quirks.
+    #[test]
+    fn score_breakdown_reveal_advances_visibility_per_stagger() {
+        use bevy::time::TimePlugin;
+
+        let mut app = App::new();
+        app.add_plugins(MinimalPlugins.build().disable::<TimePlugin>());
+        app.init_resource::<Time>();
+        app.add_systems(Update, reveal_score_breakdown);
+
+        // Spawn three rows with delays of 0.0, 0.15, and 0.30 s.
+        let stagger = MOTION_SCORE_BREAKDOWN_STAGGER_SECS;
+        let fade = MOTION_SCORE_BREAKDOWN_FADE_SECS;
+        let row0 = app
+            .world_mut()
+            .spawn((
+                ScoreBreakdownRow {
+                    delay_secs: 0.0,
+                    fade_elapsed_secs: 0.0,
+                    fade_duration_secs: fade,
+                    revealed: false,
+                },
+                Visibility::Hidden,
+            ))
+            .id();
+        let row1 = app
+            .world_mut()
+            .spawn((
+                ScoreBreakdownRow {
+                    delay_secs: stagger,
+                    fade_elapsed_secs: 0.0,
+                    fade_duration_secs: fade,
+                    revealed: false,
+                },
+                Visibility::Hidden,
+            ))
+            .id();
+        let row2 = app
+            .world_mut()
+            .spawn((
+                ScoreBreakdownRow {
+                    delay_secs: stagger * 2.0,
+                    fade_elapsed_secs: 0.0,
+                    fade_duration_secs: fade,
+                    revealed: false,
+                },
+                Visibility::Hidden,
+            ))
+            .id();
+
+        // Frame 1: `time.delta` is 0 (first frame), so only row0
+        // (delay = 0) should reveal.
+        app.update();
+        assert!(app.world().entity(row0).get::<ScoreBreakdownRow>().unwrap().revealed);
+        assert!(!app.world().entity(row1).get::<ScoreBreakdownRow>().unwrap().revealed);
+        assert!(!app.world().entity(row2).get::<ScoreBreakdownRow>().unwrap().revealed);
+
+        // Advance time by one stagger interval — row1 should reveal.
+        {
+            let mut time = app.world_mut().resource_mut::<Time>();
+            time.advance_by(std::time::Duration::from_secs_f32(stagger + 0.001));
+        }
+        app.update();
+        assert!(app.world().entity(row1).get::<ScoreBreakdownRow>().unwrap().revealed);
+        assert!(!app.world().entity(row2).get::<ScoreBreakdownRow>().unwrap().revealed);
+
+        // Advance again — row2 should reveal.
+        {
+            let mut time = app.world_mut().resource_mut::<Time>();
+            time.advance_by(std::time::Duration::from_secs_f32(stagger + 0.001));
+        }
+        app.update();
+        assert!(app.world().entity(row2).get::<ScoreBreakdownRow>().unwrap().revealed);
+    }
+
+    /// Under `AnimSpeed::Instant`, breakdown rows must spawn already
+    /// revealed and at full opacity — there should be no stagger
+    /// reveal animation at all.
+    #[test]
+    fn score_breakdown_instant_speed_skips_stagger() {
+        // Helper: simulate what `spawn_breakdown_row` constructs by
+        // checking the `instant` branch behaviour. Specifically: under
+        // Instant, scaled_duration → 0.0, so the row's stagger and
+        // fade are both zero.
+        let stagger = scaled_duration(MOTION_SCORE_BREAKDOWN_STAGGER_SECS, AnimSpeed::Instant);
+        let fade = scaled_duration(MOTION_SCORE_BREAKDOWN_FADE_SECS, AnimSpeed::Instant);
+        assert_eq!(stagger, 0.0);
+        assert_eq!(fade, 0.0);
+    }
 }