✨ add demolish mode for buildings (Issue #50)

- New 💥 Demolish button in the action bar
- Red ghost highlights building footprint on hover
- Refund: 100% within 3 min, decays linearly to 0%
- Mine teardown unblocks passability tiles and removes status label
- Nisse inside demolished mine are rescued and reset to idle
- Floor/wall/chest tiles restored to GRASS on demolish
- Build error now shows missing resources instead of generic message
- BuildingState gains builtAt field; old saves default to 0 (no refund)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,25 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+### Added
+- **Demolish Mode** (Issue #50): New 💥 Demolish button in the action bar; hover shows a red ghost over any building with a refund percentage; buildings demolished within 3 minutes return 100% of costs (linear decay to 0%); mine footprint tiles are unblocked on teardown; Nisse working inside a demolished building are rescued and resume idle; tile types are restored where applicable (floor/wall/chest → grass)
+- **Mine Building** (Issue #42): 3×2 building placeable only on resource-free ROCK tiles (costs: 200 wood + 50 stone); Nisse with mine priority walk to the entrance, disappear inside for 15 s, then reappear carrying 2 stone; up to 3 Nisse work simultaneously; ⛏ X/3 status label shown directly on the building in world space; surface rock harvesting remains functional alongside the building
+
+### Fixed
+- **Debug-Panel überlagert Nisse-Info-Panel** (Issue #41): F3-Debug-Panel weicht dynamisch aus — wenn das Nisse-Info-Panel offen ist, erscheint das Debug-Panel unterhalb davon statt darüber
+- **Stockpile-Overlay Transparenz** (Issue #39): `updateStaticPanelOpacity()` verwendete `setAlpha()` statt `setFillStyle()` — dadurch wurde die Opacity quadratisch statt linear angewendet; bei 100 % blieb das Panel sichtbar transparent
+- **Action Bar Transparenz** (Issue #40): Action Bar ignorierte `uiOpacity` komplett — Hintergrund war hardcoded auf 0.92; wird jetzt korrekt mit `uiOpacity` erstellt und per `updateStaticPanelOpacity()` live aktualisiert
+
+### Performance
+- **Event-queue timers** (Issue #36): crops, tree seedlings, and tile-recovery events now use a sorted priority queue with absolute `gameTime` timestamps instead of per-frame countdown iteration — O(due items) per tick instead of O(total items); `WorldState.gameTime` tracks the in-game clock; save migrated from v5 to v6
+
+### Added
+- **Action log in F3 debug panel** (Issue #37): last 15 actions dispatched through the adapter are shown in the F3 overlay under "Last Actions"; ring buffer maintained in `LocalAdapter`
+
+### Fixed
+- **Y-based depth sorting** (Issue #31): trees, rocks, seedlings and buildings now use `tileY + 5` as depth instead of fixed values — objects lower on screen always render in front of objects above them, regardless of spawn order; build ghost moved to depth 1000
+- **Nisse always visible** (Issue #33): Nisse sprites fixed at depth 900, always rendered above world objects
+
 ### Added
 - **Försterkreislauf** (Issue #25):
   - **Setzlinge beim Fällen**: Jeder gefällte Baum gibt 1–2 `tree_seed` in den Stockpile

src/NetworkAdapter.ts

@@ -8,12 +8,42 @@ export interface NetworkAdapter {
   onAction?: (action: GameAction) => void
 }
 
+const ACTION_LOG_SIZE = 15
+
 /** Singleplayer: apply actions immediately and synchronously */
 export class LocalAdapter implements NetworkAdapter {
   onAction?: (action: GameAction) => void
 
+  /** Ring-buffer of the last ACTION_LOG_SIZE dispatched action summaries. */
+  private _actionLog: string[] = []
+
   send(action: GameAction): void {
     stateManager.apply(action)
+    this._recordAction(action)
     this.onAction?.(action)
   }
+
+  /** Returns a copy of the recent action log (oldest first). */
+  getActionLog(): readonly string[] { return this._actionLog }
+
+  /**
+   * Appends a short summary of the action to the ring-buffer.
+   * @param action - The dispatched game action
+   */
+  private _recordAction(action: GameAction): void {
+    let entry = action.type
+    if ('tileX' in action && 'tileY' in action)
+      entry += ` (${(action as any).tileX},${(action as any).tileY})`
+    else if ('villagerId' in action)
+      entry += ` v=…${(action as any).villagerId.slice(-4)}`
+    else if ('resourceId' in action)
+      entry += ` r=…${(action as any).resourceId.slice(-4)}`
+    else if ('cropId' in action)
+      entry += ` c=…${(action as any).cropId.slice(-4)}`
+    else if ('seedlingId' in action)
+      entry += ` s=…${(action as any).seedlingId.slice(-4)}`
+
+    if (this._actionLog.length >= ACTION_LOG_SIZE) this._actionLog.shift()
+    this._actionLog.push(entry)
+  }
 }

src/StateManager.ts

@@ -2,15 +2,42 @@ import { SAVE_KEY, WORLD_TILES, CROP_CONFIGS, TREE_SEEDLING_STAGE_MS, TILE_RECOV
 import type { GameStateData, GameAction, PlayerState, WorldState, ItemId } from './types'
 import { TileType } from './types'
 
+// ─── Internal queue entry types ───────────────────────────────────────────────
+
+/** Scheduled crop-growth entry. Two entries are created per stage (normal + watered path). */
+interface CropEntry {
+  id: string
+  fireAt: number
+  expectedStage: number
+  /** If true this entry only fires when crop.watered === true. */
+  wateredPath: boolean
+}
+
+/** Scheduled seedling-growth entry. One entry per stage. */
+interface SeedlingEntry {
+  id: string
+  fireAt: number
+  expectedStage: number
+}
+
+/** Scheduled tile-recovery entry. One entry per tile. */
+interface RecoveryEntry {
+  key: string
+  fireAt: number
+}
+
+// ─── State factories ───────────────────────────────────────────────────────────
+
 const DEFAULT_PLAYER: PlayerState = {
   id: 'player1',
   x: 8192, y: 8192,
-  inventory: {},  // empty — seeds now in stockpile
+  inventory: {},
 }
 
 function makeEmptyWorld(seed: number): WorldState {
   return {
     seed,
+    gameTime: 0,
     tiles: new Array(WORLD_TILES * WORLD_TILES).fill(3),
     resources: {},
     buildings: {},
@@ -25,21 +52,164 @@ function makeEmptyWorld(seed: number): WorldState {
 
 function makeDefaultState(): GameStateData {
   return {
-    version: 5,
+    version: 6,
     world: makeEmptyWorld(Math.floor(Math.random() * 999999)),
     player: { ...DEFAULT_PLAYER, inventory: { ...DEFAULT_PLAYER.inventory } },
   }
 }
 
+// ─── StateManager ─────────────────────────────────────────────────────────────
+
 class StateManager {
   private state: GameStateData
 
+  // In-memory event queues (not persisted; rebuilt from state on load).
+  private cropQueue:     CropEntry[]     = []
+  private seedlingQueue: SeedlingEntry[] = []
+  private recoveryQueue: RecoveryEntry[] = []
+
   constructor() {
     this.state = this.load() ?? makeDefaultState()
+    this.rebuildQueues()
   }
 
   getState(): Readonly<GameStateData> { return this.state }
 
+  /** Returns the current accumulated in-game time in milliseconds. */
+  getGameTime(): number { return this.state.world.gameTime }
+
+  /**
+   * Advances the in-game clock by delta milliseconds.
+   * Must be called once per frame before any tick methods.
+   * @param delta - Frame delta in milliseconds
+   */
+  advanceTime(delta: number): void {
+    this.state.world.gameTime += delta
+  }
+
+  // ─── Queue helpers ──────────────────────────────────────────────────────────
+
+  /**
+   * Inserts an entry into a sorted queue in ascending fireAt order.
+   * Uses binary search for O(log n) position find; O(n) splice insert.
+   */
+  private static insertSorted<T extends { fireAt: number }>(queue: T[], entry: T): void {
+    let lo = 0, hi = queue.length
+    while (lo < hi) {
+      const mid = (lo + hi) >>> 1
+      if (queue[mid].fireAt <= entry.fireAt) lo = mid + 1
+      else hi = mid
+    }
+    queue.splice(lo, 0, entry)
+  }
+
+  /** Enqueues both growth entries (normal + watered path) for a crop's current stage. */
+  private enqueueCropStage(id: string, expectedStage: number, growsAt: number, growsAtWatered: number): void {
+    StateManager.insertSorted(this.cropQueue, { id, fireAt: growsAt,        expectedStage, wateredPath: false })
+    StateManager.insertSorted(this.cropQueue, { id, fireAt: growsAtWatered, expectedStage, wateredPath: true  })
+  }
+
+  /**
+   * Rebuilds all three event queues from the persisted state.
+   * Called once after construction or load.
+   */
+  private rebuildQueues(): void {
+    this.cropQueue     = []
+    this.seedlingQueue = []
+    this.recoveryQueue = []
+
+    for (const crop of Object.values(this.state.world.crops)) {
+      if (crop.stage >= crop.maxStage) continue
+      this.enqueueCropStage(crop.id, crop.stage, crop.growsAt, crop.growsAtWatered)
+    }
+
+    for (const s of Object.values(this.state.world.treeSeedlings)) {
+      if (s.stage < 2) {
+        StateManager.insertSorted(this.seedlingQueue, { id: s.id, fireAt: s.growsAt, expectedStage: s.stage })
+      }
+    }
+
+    for (const [key, fireAt] of Object.entries(this.state.world.tileRecovery)) {
+      StateManager.insertSorted(this.recoveryQueue, { key, fireAt })
+    }
+  }
+
+  // ─── Tick methods ──────────────────────────────────────────────────────────
+
+  /**
+   * Drains the crop queue up to the current gameTime.
+   * Returns IDs of crops that advanced a stage this frame.
+   */
+  tickCrops(): string[] {
+    const now = this.state.world.gameTime
+    const advanced: string[] = []
+
+    while (this.cropQueue.length > 0 && this.cropQueue[0].fireAt <= now) {
+      const entry = this.cropQueue.shift()!
+      const crop = this.state.world.crops[entry.id]
+      if (!crop || crop.stage !== entry.expectedStage) continue  // already removed or stale stage
+      if (entry.wateredPath && !crop.watered) continue           // fast-path skipped: not watered
+
+      crop.stage++
+      advanced.push(crop.id)
+
+      if (crop.stage < crop.maxStage) {
+        const cfg = CROP_CONFIGS[crop.kind]
+        crop.growsAt        = now + cfg.stageTimeMs
+        crop.growsAtWatered = now + cfg.stageTimeMs / 2
+        this.enqueueCropStage(crop.id, crop.stage, crop.growsAt, crop.growsAtWatered)
+      }
+    }
+    return advanced
+  }
+
+  /**
+   * Drains the seedling queue up to the current gameTime.
+   * Returns IDs of seedlings that advanced a stage this frame.
+   */
+  tickSeedlings(): string[] {
+    const now = this.state.world.gameTime
+    const advanced: string[] = []
+
+    while (this.seedlingQueue.length > 0 && this.seedlingQueue[0].fireAt <= now) {
+      const entry = this.seedlingQueue.shift()!
+      const s = this.state.world.treeSeedlings[entry.id]
+      if (!s || s.stage !== entry.expectedStage) continue  // removed or stale
+
+      s.stage = Math.min(s.stage + 1, 2)
+      advanced.push(s.id)
+
+      if (s.stage < 2) {
+        s.growsAt = now + TREE_SEEDLING_STAGE_MS
+        StateManager.insertSorted(this.seedlingQueue, { id: s.id, fireAt: s.growsAt, expectedStage: s.stage })
+      }
+    }
+    return advanced
+  }
+
+  /**
+   * Drains the tile-recovery queue up to the current gameTime.
+   * Returns keys ("tileX,tileY") of tiles that have reverted to GRASS.
+   */
+  tickTileRecovery(): string[] {
+    const now = this.state.world.gameTime
+    const recovered: string[] = []
+
+    while (this.recoveryQueue.length > 0 && this.recoveryQueue[0].fireAt <= now) {
+      const entry = this.recoveryQueue.shift()!
+      const fireAt = this.state.world.tileRecovery[entry.key]
+      // Skip if the entry was superseded (tile re-planted, resetting its fireAt)
+      if (fireAt === undefined || fireAt > now) continue
+      delete this.state.world.tileRecovery[entry.key]
+      recovered.push(entry.key)
+      const [tx, ty] = entry.key.split(',').map(Number)
+      this.state.world.tiles[ty * WORLD_TILES + tx] = TileType.GRASS
+    }
+    return recovered
+  }
+
+  // ─── State mutations ───────────────────────────────────────────────────────
+
   apply(action: GameAction): void {
     const s = this.state
     const w = s.world
@@ -63,10 +233,9 @@ class StateManager {
         w.tiles[action.tileY * WORLD_TILES + action.tileX] = action.tile; break
 
       case 'PLACE_BUILDING': {
-        w.buildings[action.building.id] = action.building
+        w.buildings[action.building.id] = { ...action.building, builtAt: w.gameTime }
         for (const [k, v] of Object.entries(action.costs))
           w.stockpile[k as ItemId] = Math.max(0, (w.stockpile[k as ItemId] ?? 0) - (v ?? 0))
-        // Automatically create an empty forester zone when a forester hut is placed
         if (action.building.kind === 'forester_hut') {
           w.foresterZones[action.building.id] = { buildingId: action.building.id, tiles: [] }
         }
@@ -74,7 +243,6 @@ class StateManager {
       }
 
       case 'REMOVE_BUILDING':
-        // Remove associated forester zone when the hut is demolished
         if (w.buildings[action.buildingId]?.kind === 'forester_hut') {
           delete w.foresterZones[action.buildingId]
         }
@@ -90,22 +258,24 @@ class StateManager {
         w.crops[action.crop.id] = { ...action.crop }
         const have = w.stockpile[action.seedItem] ?? 0
         w.stockpile[action.seedItem] = Math.max(0, have - 1)
+        // Enqueue growth timers for both normal and watered paths
+        this.enqueueCropStage(action.crop.id, 0, action.crop.growsAt, action.crop.growsAtWatered)
         break
       }
 
       case 'WATER_CROP': {
         const c = w.crops[action.cropId]; if (c) c.watered = true; break
+        // No queue change needed — the wateredPath entry was enqueued at planting time
       }
 
       case 'HARVEST_CROP': {
         delete w.crops[action.cropId]
         for (const [k, v] of Object.entries(action.rewards))
           w.stockpile[k as ItemId] = (w.stockpile[k as ItemId] ?? 0) + (v ?? 0)
+        // Stale queue entries will be skipped automatically (crop no longer exists)
         break
       }
 
-      // ── Villager actions ──────────────────────────────────────────────────
-
       case 'SPAWN_VILLAGER':
         w.villagers[action.villager.id] = { ...action.villager }; break
 
@@ -163,22 +333,30 @@ class StateManager {
       case 'PLANT_TREE_SEED': {
         w.treeSeedlings[action.seedling.id] = { ...action.seedling }
         w.stockpile.tree_seed = Math.max(0, (w.stockpile.tree_seed ?? 0) - 1)
-        // Cancel any tile recovery on this tile
         delete w.tileRecovery[`${action.seedling.tileX},${action.seedling.tileY}`]
+        // Enqueue growth timer
+        StateManager.insertSorted(this.seedlingQueue, {
+          id: action.seedling.id, fireAt: action.seedling.growsAt, expectedStage: 0
+        })
         break
       }
 
       case 'REMOVE_TREE_SEEDLING':
         delete w.treeSeedlings[action.seedlingId]
+        // Stale queue entries will be skipped automatically
         break
 
       case 'SPAWN_RESOURCE':
         w.resources[action.resource.id] = { ...action.resource }
         break
 
-      case 'TILE_RECOVERY_START':
+      case 'TILE_RECOVERY_START': {
-        w.tileRecovery[`${action.tileX},${action.tileY}`] = TILE_RECOVERY_MS
+        const fireAt = w.gameTime + TILE_RECOVERY_MS
+        const key = `${action.tileX},${action.tileY}`
+        w.tileRecovery[key] = fireAt
+        StateManager.insertSorted(this.recoveryQueue, { key, fireAt })
         break
+      }
 
       case 'FORESTER_ZONE_UPDATE': {
         const zone = w.foresterZones[action.buildingId]
@@ -188,60 +366,7 @@ class StateManager {
     }
   }
 
-  tickCrops(delta: number): string[] {
+  // ─── Persistence ───────────────────────────────────────────────────────────
-    const advanced: string[] = []
-    for (const crop of Object.values(this.state.world.crops)) {
-      if (crop.stage >= crop.maxStage) continue
-      crop.stageTimerMs -= delta * (crop.watered ? 2 : 1)
-      if (crop.stageTimerMs <= 0) {
-        crop.stage = Math.min(crop.stage + 1, crop.maxStage)
-        crop.stageTimerMs = CROP_CONFIGS[crop.kind].stageTimeMs
-        advanced.push(crop.id)
-      }
-    }
-    return advanced
-  }
-
-  /**
-   * Advances all tree-seedling growth timers.
-   * Returns IDs of seedlings that have reached stage 2 (ready to mature into a tree).
-   * @param delta - Frame delta in milliseconds
-   * @returns Array of seedling IDs that are now mature
-   */
-  tickSeedlings(delta: number): string[] {
-    const advanced: string[] = []
-    for (const s of Object.values(this.state.world.treeSeedlings)) {
-      s.stageTimerMs -= delta
-      if (s.stageTimerMs <= 0) {
-        s.stage = Math.min(s.stage + 1, 2)
-        s.stageTimerMs = TREE_SEEDLING_STAGE_MS
-        advanced.push(s.id)
-      }
-    }
-    return advanced
-  }
-
-  /**
-   * Ticks tile-recovery timers.
-   * Returns keys ("tileX,tileY") of tiles that have now recovered back to GRASS.
-   * @param delta - Frame delta in milliseconds
-   * @returns Array of recovered tile keys
-   */
-  tickTileRecovery(delta: number): string[] {
-    const recovered: string[] = []
-    const rec = this.state.world.tileRecovery
-    for (const key of Object.keys(rec)) {
-      rec[key] -= delta
-      if (rec[key] <= 0) {
-        delete rec[key]
-        recovered.push(key)
-        // Update tiles array directly (DARK_GRASS → GRASS)
-        const [tx, ty] = key.split(',').map(Number)
-        this.state.world.tiles[ty * WORLD_TILES + tx] = TileType.GRASS
-      }
-    }
-    return recovered
-  }
 
   save(): void {
     try { localStorage.setItem(SAVE_KEY, JSON.stringify(this.state)) } catch (_) {}
@@ -252,24 +377,46 @@ class StateManager {
       const raw = localStorage.getItem(SAVE_KEY)
       if (!raw) return null
       const p = JSON.parse(raw) as GameStateData
-      if (p.version !== 5) return null
+
+      // ── Migrate v5 → v6: countdown timers → absolute gameTime timestamps ──
+      if ((p.version as number) === 5) {
+        p.world.gameTime = 0
+        for (const crop of Object.values(p.world.crops)) {
+          const old = crop as any
+          const ms = old.stageTimerMs ?? CROP_CONFIGS[crop.kind]?.stageTimeMs ?? 20_000
+          crop.growsAt        = ms
+          crop.growsAtWatered = ms / 2
+          delete old.stageTimerMs
+        }
+        for (const s of Object.values(p.world.treeSeedlings)) {
+          const old = s as any
+          s.growsAt = old.stageTimerMs ?? TREE_SEEDLING_STAGE_MS
+          delete old.stageTimerMs
+        }
+        // tileRecovery values were remaining-ms countdowns; with gameTime=0 they equal fireAt directly
+        p.version = 6
+      }
+
+      if (p.version !== 6) return null
+
       if (!p.world.crops)          p.world.crops          = {}
       if (!p.world.villagers)      p.world.villagers      = {}
       if (!p.world.stockpile)      p.world.stockpile      = {}
       if (!p.world.treeSeedlings)  p.world.treeSeedlings  = {}
       if (!p.world.tileRecovery)   p.world.tileRecovery   = {}
       if (!p.world.foresterZones)  p.world.foresterZones  = {}
-      // Reset in-flight AI states to idle on load so runtime timers start fresh
+      if (!p.world.gameTime)       p.world.gameTime       = 0
+
       for (const v of Object.values(p.world.villagers)) {
         if (v.aiState === 'walking' || v.aiState === 'working') v.aiState = 'idle'
-        // Migrate older saves that don't have the forester priority
         if (typeof (v.priorities as any).forester === 'undefined') v.priorities.forester = 4
       }
-      // Rebuild forester zones for huts that predate the foresterZones field
       for (const b of Object.values(p.world.buildings)) {
         if (b.kind === 'forester_hut' && !p.world.foresterZones[b.id]) {
           p.world.foresterZones[b.id] = { buildingId: b.id, tiles: [] }
         }
+        // Migrate buildings without builtAt (pre-demolish saves): set to 0 = no refund
+        if (typeof (b as any).builtAt === 'undefined') (b as any).builtAt = 0
       }
       return p
     } catch (_) { return null }
@@ -278,6 +425,7 @@ class StateManager {
   reset(): void {
     localStorage.removeItem(SAVE_KEY)
     this.state = makeDefaultState()
+    this.rebuildQueues()
   }
 }
 

src/config.ts

@@ -20,8 +20,18 @@ export const BUILDING_COSTS: Record<BuildingType, Record<string, number>> = {
   bed:           { wood: 6 },
   stockpile_zone:{ wood: 0 },
   forester_hut:  { wood: 50 },
+  mine:          { stone: 50, wood: 200 },
 }
 
+/** Maximum number of Nisse that can work inside a mine simultaneously. */
+export const MINE_CAPACITY = 3
+
+/** Milliseconds a Nisse spends inside a mine per visit. */
+export const MINE_WORK_MS = 15_000
+
+/** Stone yielded per mine visit. */
+export const MINE_STONE_YIELD = 2
+
 /** Max Chebyshev radius (in tiles) that a forester hut's zone can extend. */
 export const FORESTER_ZONE_RADIUS = 5
 
@@ -51,6 +61,9 @@ export const VILLAGER_NAMES = [
   'Orla','Pike','Quinn','Rook','Sera','Tull','Uma','Vex',
 ]
 
+/** Milliseconds after placement during which demolishing gives a full refund (linearly decays to 0%). */
+export const DEMOLISH_REFUND_MS = 180_000   // 3 minutes
+
 export const SAVE_KEY = 'tg_save_v5'
 export const AUTOSAVE_INTERVAL = 30_000
 

src/scenes/GameScene.ts

@@ -1,5 +1,5 @@
 import Phaser from 'phaser'
-import { AUTOSAVE_INTERVAL, TILE_SIZE } from '../config'
+import { AUTOSAVE_INTERVAL, TILE_SIZE, MINE_CAPACITY } from '../config'
 import { TileType } from '../types'
 import type { BuildingType } from '../types'
 import { stateManager } from '../StateManager'
@@ -27,6 +27,8 @@ export class GameScene extends Phaser.Scene {
   foresterZoneSystem!: ForesterZoneSystem
   private autosaveTimer = 0
   private menuOpen = false
+  /** World-space status labels for mine buildings, keyed by building ID. */
+  private mineStatusTexts = new Map<string, Phaser.GameObjects.Text>()
 
   constructor() { super({ key: 'Game' }) }
 
@@ -46,7 +48,7 @@ export class GameScene extends Phaser.Scene {
     this.villagerSystem.init(this.resourceSystem, this.farmingSystem)
     this.treeSeedlingSystem  = new TreeSeedlingSystem(this, this.adapter, this.worldSystem)
     this.foresterZoneSystem  = new ForesterZoneSystem(this, this.adapter)
-    this.debugSystem         = new DebugSystem(this, this.villagerSystem, this.worldSystem)
+    this.debugSystem         = new DebugSystem(this, this.villagerSystem, this.worldSystem, this.adapter)
 
     this.worldSystem.create()
     this.renderPersistentObjects()
@@ -62,6 +64,31 @@ export class GameScene extends Phaser.Scene {
       this.events.emit('toast', msg)
       this.renderPersistentObjects()
     }
+    this.buildingSystem.onDemolishModeChange = (active) => this.events.emit('demolishModeChanged', active)
+    this.buildingSystem.onDemolished = (building, refund) => {
+      // Remove the building sprite
+      this.children.getByName(`bobj_${building.id}`)?.destroy()
+
+      // Mine-specific cleanup: unblock the 5 passability tiles and remove status label
+      if (building.kind === 'mine') {
+        for (let dy = 0; dy < 2; dy++) {
+          for (let dx = 0; dx < 3; dx++) {
+            if (dx === 1 && dy === 1) continue  // entrance tile was never blocked
+            this.worldSystem.removeResourceTile(building.tileX + dx, building.tileY + dy)
+          }
+        }
+        this.mineStatusTexts.get(building.id)?.destroy()
+        this.mineStatusTexts.delete(building.id)
+      }
+
+      // Rescue any Nisse working in or walking to this building
+      this.villagerSystem.rescueNisseFromBuilding(building.id)
+
+      const refundMsg = Object.keys(refund).length
+        ? ` (+${Object.entries(refund).map(([k, v]) => `${v} ${k}`).join(', ')})`
+        : ' (no refund)'
+      this.events.emit('toast', `Demolished ${building.kind}${refundMsg}`)
+    }
 
     this.farmingSystem.create()
     this.farmingSystem.onMessage     = (msg)         => this.events.emit('toast', msg)
@@ -100,7 +127,7 @@ export class GameScene extends Phaser.Scene {
     // Detect left-clicks on forester huts to open the zone panel
     this.input.on('pointerdown', (ptr: Phaser.Input.Pointer) => {
       if (ptr.rightButtonDown() || this.menuOpen) return
-      if (this.buildingSystem.isActive()) return
+      if (this.buildingSystem.isActive() || this.buildingSystem.isDemolishActive()) return
       const tileX = Math.floor(ptr.worldX / TILE_SIZE)
       const tileY = Math.floor(ptr.worldY / TILE_SIZE)
       const state = stateManager.getState()
@@ -114,7 +141,9 @@ export class GameScene extends Phaser.Scene {
 
     this.scene.launch('UI')
 
-    this.events.on('selectBuilding', (kind: BuildingType) => this.buildingSystem.selectBuilding(kind))
+    this.events.on('selectBuilding',    (kind: BuildingType) => this.buildingSystem.selectBuilding(kind))
+    this.events.on('activateDemolish',  () => this.buildingSystem.activateDemolish())
+    this.events.on('deactivateDemolish', () => this.buildingSystem.deactivateDemolish())
     this.events.on('uiMenuOpen',  () => { this.menuOpen = true })
     this.events.on('uiMenuClose', () => { this.menuOpen = false })
     this.events.on('uiRequestBuildMenu', () => {
@@ -145,6 +174,9 @@ export class GameScene extends Phaser.Scene {
   update(_time: number, delta: number): void {
     if (this.menuOpen) return
 
+    // Advance the in-game clock first so all tick methods see the updated time
+    stateManager.advanceTime(delta)
+
     this.cameraSystem.update(delta)
 
     this.resourceSystem.update(delta)
@@ -153,8 +185,8 @@ export class GameScene extends Phaser.Scene {
     this.villagerSystem.update(delta)
     this.debugSystem.update()
 
-    // Tick tile-recovery timers; refresh canvas for any tiles that reverted to GRASS
+    // Drain tile-recovery queue; refresh canvas for any tiles that reverted to GRASS
-    const recovered = stateManager.tickTileRecovery(delta)
+    const recovered = stateManager.tickTileRecovery()
     for (const key of recovered) {
       const [tx, ty] = key.split(',').map(Number)
       this.worldSystem.refreshTerrainTile(tx, ty, TileType.GRASS)
@@ -162,6 +194,7 @@ export class GameScene extends Phaser.Scene {
 
     this.events.emit('cameraMoved', this.cameraSystem.getCenterTile())
     this.buildingSystem.update()
+    this.updateMineStatusLabels()
 
     this.autosaveTimer -= delta
     if (this.autosaveTimer <= 0) {
@@ -179,18 +212,19 @@ export class GameScene extends Phaser.Scene {
       const name = `bobj_${building.id}`
       if (this.children.getByName(name)) continue
 
+      const worldDepth = building.tileY + 5
       if (building.kind === 'chest') {
-        const g = this.add.graphics().setName(name).setDepth(8)
+        const g = this.add.graphics().setName(name).setDepth(worldDepth)
         g.fillStyle(0x8B4513); g.fillRect(wx - 10, wy - 7, 20, 14)
         g.fillStyle(0xCD853F); g.fillRect(wx - 9, wy - 6, 18, 6)
         g.lineStyle(1, 0x5C3317); g.strokeRect(wx - 10, wy - 7, 20, 14)
       } else if (building.kind === 'bed') {
-        this.add.image(wx, wy, 'bed_obj').setName(name).setDepth(8)
+        this.add.image(wx, wy, 'bed_obj').setName(name).setDepth(worldDepth)
       } else if (building.kind === 'stockpile_zone') {
         this.add.image(wx, wy, 'stockpile_obj').setName(name).setDepth(4).setAlpha(0.8)
       } else if (building.kind === 'forester_hut') {
         // Draw a simple log-cabin silhouette for the forester hut
-        const g = this.add.graphics().setName(name).setDepth(8)
+        const g = this.add.graphics().setName(name).setDepth(worldDepth)
         // Body
         g.fillStyle(0x6B3F16); g.fillRect(wx - 12, wy - 9, 24, 18)
         // Roof
@@ -199,10 +233,105 @@ export class GameScene extends Phaser.Scene {
         g.fillStyle(0x2a1500); g.fillRect(wx - 4, wy + 1, 8, 8)
         // Tree symbol on the roof
         g.fillStyle(0x228B22); g.fillTriangle(wx - 6, wy - 11, wx + 6, wy - 11, wx, wy - 20)
+      } else if (building.kind === 'mine') {
+        this.renderMineBuilding(building)
       }
     }
   }
 
+  /**
+   * Draws a mine building (3×2 tiles) at the given building position.
+   * Blocks the 5 non-entrance tiles in the WorldSystem passability index and
+   * creates a world-space status label showing current / max workers.
+   * @param building - The mine building state to render
+   */
+  private renderMineBuilding(building: ReturnType<typeof stateManager.getState>['world']['buildings'][string]): void {
+    const name  = `bobj_${building.id}`
+    const left  = building.tileX * TILE_SIZE
+    const top   = building.tileY * TILE_SIZE
+    const W = TILE_SIZE * 3   // 96 px
+    const H = TILE_SIZE * 2   // 64 px
+
+    const g = this.add.graphics().setName(name).setDepth(building.tileY + 6)
+
+    // Rocky stone face
+    g.fillStyle(0x424242); g.fillRect(left, top, W, H)
+
+    // Stone texture highlights — top row
+    g.fillStyle(0x5a5a5a, 0.7)
+    g.fillRect(left + 4,  top + 3,  20, 10)
+    g.fillRect(left + 28, top + 5,  18,  9)
+    g.fillRect(left + 52, top + 3,  22, 11)
+    g.fillRect(left + 76, top + 5,  14, 10)
+
+    // Stone highlights — bottom row sides (left of entrance, right of entrance)
+    g.fillRect(left + 4,  top + 36, 16, 10)
+    g.fillRect(left + 70, top + 37, 18, 10)
+    g.fillStyle(0x3a3a3a, 0.5)
+    g.fillRect(left + 6,  top + 50, 18,  8)
+    g.fillRect(left + 68, top + 51, 16,  8)
+
+    // Wooden support posts flanking entrance
+    g.fillStyle(0x8B4513)
+    g.fillRect(left + 30, top + 22, 8, H - 22)   // left post
+    g.fillRect(left + 58, top + 22, 8, H - 22)   // right post
+
+    // Lintel beam across top of entrance
+    g.fillStyle(0x6B3311)
+    g.fillRect(left + 28, top + 20, 40, 10)
+
+    // Horizontal wood grain lines on posts
+    g.lineStyle(1, 0x5C2A00, 0.4)
+    for (let yy = top + 28; yy < top + H; yy += 7) {
+      g.lineBetween(left + 30, yy, left + 38, yy)
+      g.lineBetween(left + 58, yy, left + 66, yy)
+    }
+
+    // Mine shaft (dark entrance opening)
+    g.fillStyle(0x0d0d0d); g.fillRect(left + 38, top + 30, 20, H - 30)
+    g.fillStyle(0x000000, 0.5); g.fillRect(left + 38, top + 30, 4, H - 30)   // left shadow
+
+    // Rail track at entrance floor
+    g.fillStyle(0x888888); g.fillRect(left + 42, top + H - 5, 12, 2)
+    g.fillStyle(0x777777)
+    g.fillRect(left + 44, top + H - 8, 2, 6)
+    g.fillRect(left + 50, top + H - 8, 2, 6)
+
+    // Block the 5 non-entrance tiles in the passability index.
+    // Entrance = (tileX+1, tileY+1) — stays passable.
+    for (let dy = 0; dy < 2; dy++) {
+      for (let dx = 0; dx < 3; dx++) {
+        if (dx === 1 && dy === 1) continue   // entrance tile: skip
+        this.worldSystem.addResourceTile(building.tileX + dx, building.tileY + dy)
+      }
+    }
+
+    // Create the ⛏ X/3 status label above the building (only once)
+    if (!this.mineStatusTexts.has(building.id)) {
+      const cx = left + W / 2
+      const st = this.add.text(cx, top - 4, `⛏ 0/${MINE_CAPACITY}`, {
+        fontSize: '10px', color: '#ffdd88', fontFamily: 'monospace',
+        backgroundColor: '#00000088', padding: { x: 2, y: 1 },
+      }).setOrigin(0.5, 1).setDepth(building.tileY + 7)
+      this.mineStatusTexts.set(building.id, st)
+    }
+  }
+
+  /**
+   * Updates the ⛏ X/3 status label for every mine building each frame.
+   * Counts Nisse currently working (inside) the mine from the game state.
+   */
+  private updateMineStatusLabels(): void {
+    const state = stateManager.getState()
+    const villagers = Object.values(state.world.villagers)
+    for (const [buildingId, text] of this.mineStatusTexts) {
+      const count = villagers.filter(
+        v => v.job?.targetId === buildingId && v.aiState === 'working'
+      ).length
+      text.setText(`⛏ ${count}/${MINE_CAPACITY}`)
+    }
+  }
+
   /** Saves game state and destroys all systems cleanly on scene shutdown. */
   shutdown(): void {
     stateManager.save()

src/scenes/UIScene.ts

@@ -67,9 +67,11 @@ export class UIScene extends Phaser.Scene {
   private actionBuildLabel!: Phaser.GameObjects.Text
   private actionNisseBtn!: Phaser.GameObjects.Rectangle
   private actionNisseLabel!: Phaser.GameObjects.Text
+  private actionDemolishBtn!: Phaser.GameObjects.Rectangle
+  private actionDemolishLabel!: Phaser.GameObjects.Text
   private actionTrayGroup!: Phaser.GameObjects.Group
   private actionTrayVisible = false
-  private activeCategory: 'build' | 'nisse' | null = null
+  private activeCategory: 'build' | 'nisse' | 'demolish' | null = null
 
   constructor() { super({ key: 'UI' }) }
 
@@ -89,10 +91,16 @@ export class UIScene extends Phaser.Scene {
     this.createActionBar()
 
     const gameScene = this.scene.get('Game')
-    gameScene.events.on('buildModeChanged', (a: boolean, b: BuildingType) => this.onBuildModeChanged(a, b))
+    gameScene.events.on('buildModeChanged',   (a: boolean, b: BuildingType) => this.onBuildModeChanged(a, b))
-    gameScene.events.on('farmToolChanged',  (t: FarmingTool, l: string) => this.onFarmToolChanged(t, l))
+    gameScene.events.on('farmToolChanged',    (t: FarmingTool, l: string) => this.onFarmToolChanged(t, l))
-    gameScene.events.on('toast',            (m: string) => this.showToast(m))
+    gameScene.events.on('toast',              (m: string) => this.showToast(m))
-    gameScene.events.on('openBuildMenu',    () => this.toggleBuildMenu())
+    gameScene.events.on('openBuildMenu',      () => this.toggleBuildMenu())
+    gameScene.events.on('demolishModeChanged', (active: boolean) => {
+      if (!active && this.activeCategory === 'demolish') {
+        this.activeCategory = null
+        this.updateCategoryHighlights()
+      }
+    })
 
     this.input.keyboard!.addKey(Phaser.Input.Keyboard.KeyCodes.B)
       .on('down', () => gameScene.events.emit('uiRequestBuildMenu'))
@@ -229,9 +237,10 @@ export class UIScene extends Phaser.Scene {
       { kind: 'bed',            label: '🛏 Bed',          cost: '6 wood  (+1 villager)' },
       { kind: 'stockpile_zone', label: '📦 Stockpile',   cost: 'free  (workers deliver here)' },
       { kind: 'forester_hut',   label: '🌲 Forester Hut', cost: '50 wood' },
+      { kind: 'mine',           label: '⛏ Mine',          cost: '200 wood + 50 stone  (place on ROCK)' },
     ]
-    const menuX = this.scale.width / 2 - 150, menuY = this.scale.height / 2 - 168
+    const menuX = this.scale.width / 2 - 150, menuY = this.scale.height / 2 - 186
-    const bg = this.add.rectangle(menuX, menuY, 300, 326, 0x000000, this.uiOpacity).setOrigin(0,0).setScrollFactor(0).setDepth(200)
+    const bg = this.add.rectangle(menuX, menuY, 300, 372, 0x000000, this.uiOpacity).setOrigin(0,0).setScrollFactor(0).setDepth(200)
     this.buildMenuGroup.add(bg)
     this.buildMenuGroup.add(this.add.text(menuX + 150, menuY + 14, 'BUILD MENU  [B/ESC]', { fontSize: '11px', color: '#aaaaaa', fontFamily: 'monospace' }).setOrigin(0.5,0).setScrollFactor(0).setDepth(201))
 
@@ -405,7 +414,7 @@ export class UIScene extends Phaser.Scene {
   /** Creates the debug panel text object (initially hidden). */
   private createDebugPanel(): void {
     const hexAlpha = Math.round(this.uiOpacity * 255).toString(16).padStart(2, '0')
-    this.debugPanelText = this.add.text(10, 80, '', {
+    this.debugPanelText = this.add.text(10, 10, '', {
       fontSize: '12px',
       color: '#cccccc',
       backgroundColor: `#000000${hexAlpha}`,
@@ -419,9 +428,20 @@ export class UIScene extends Phaser.Scene {
   private toggleDebugPanel(): void {
     this.debugActive = !this.debugActive
     this.debugPanelText.setVisible(this.debugActive)
+    this.repositionDebugPanel()
     this.scene.get('Game').events.emit('debugToggle')
   }
 
+  /**
+   * Repositions the debug panel to avoid overlapping the Nisse info panel.
+   * When the Nisse info panel is open, the debug panel shifts below it.
+   */
+  private repositionDebugPanel(): void {
+    const NISSE_PANEL_H = 120 + 10 * 14 + 16  // matches buildNisseInfoPanel: 276px
+    const debugY = this.nisseInfoVisible ? 10 + NISSE_PANEL_H + 10 : 10
+    this.debugPanelText.setY(debugY)
+  }
+
   /**
    * Reads current debug data from DebugSystem and updates the panel text.
    * Called every frame while debug mode is active.
@@ -463,6 +483,9 @@ export class UIScene extends Phaser.Scene {
       '',
       `Paths: ${data.activePaths} (cyan lines in world)`,
       '',
+      '── Last Actions ───────────────',
+      ...(data.actionLog.length > 0 ? data.actionLog : ['—']),
+      '',
       '[F3] close',
     ])
   }
@@ -548,9 +571,9 @@ export class UIScene extends Phaser.Scene {
     if (this.nisseInfoVisible)     { this.closeNisseInfoPanel();                      return }
     if (this.settingsVisible)      { this.closeSettings();                            return }
     if (this.escMenuVisible)       { this.closeEscMenu();                             return }
-    // Build/farm mode: let BuildingSystem / FarmingSystem handle their own ESC key.
+    // Build/farm/demolish mode: let their systems handle ESC. Skip opening the ESC menu.
-    // We only skip opening the ESC menu while those modes are active.
     if (this.inBuildMode || this.inFarmMode) return
+    if (this.activeCategory === 'demolish') { this.deactivateCategory(); return }
     this.openEscMenu()
   }
 
@@ -780,11 +803,13 @@ export class UIScene extends Phaser.Scene {
 
   /**
    * Applies the current uiOpacity to all static UI elements that are not
-   * rebuilt on open (stockpile panel, debug panel background).
+   * rebuilt on open (stockpile panel, action bar, debug panel background).
    * Called whenever uiOpacity changes.
    */
   private updateStaticPanelOpacity(): void {
-    this.stockpilePanel.setAlpha(this.uiOpacity)
+    this.stockpilePanel.setFillStyle(0x000000, this.uiOpacity)
+    this.actionBarBg.setFillStyle(0x080808, this.uiOpacity)
+    this.updateCategoryHighlights()
     const hexAlpha = Math.round(this.uiOpacity * 255).toString(16).padStart(2, '0')
     this.debugPanelText.setStyle({ backgroundColor: `#000000${hexAlpha}` })
   }
@@ -874,6 +899,7 @@ export class UIScene extends Phaser.Scene {
     this.nisseInfoId = villagerId
     this.nisseInfoVisible = true
     this.buildNisseInfoPanel()
+    this.repositionDebugPanel()
   }
 
   /** Closes and destroys the Nisse info panel. */
@@ -883,6 +909,7 @@ export class UIScene extends Phaser.Scene {
     this.nisseInfoId = null
     this.nisseInfoGroup.destroy(true)
     this.nisseInfoGroup = this.add.group()
+    this.repositionDebugPanel()
   }
 
   /**
@@ -1166,16 +1193,16 @@ export class UIScene extends Phaser.Scene {
     const { width, height } = this.scale
     const barY = height - UIScene.BAR_H
 
-    this.actionBarBg = this.add.rectangle(0, barY, width, UIScene.BAR_H, 0x080808, 0.92)
+    this.actionBarBg = this.add.rectangle(0, barY, width, UIScene.BAR_H, 0x080808, this.uiOpacity)
       .setOrigin(0, 0).setScrollFactor(0).setDepth(300)
 
-    this.actionBuildBtn = this.add.rectangle(8, barY + 8, 88, 32, 0x1a3a1a, 0.9)
+    this.actionBuildBtn = this.add.rectangle(8, barY + 8, 88, 32, 0x1a3a1a, this.uiOpacity)
       .setOrigin(0, 0).setScrollFactor(0).setDepth(301).setInteractive()
     this.actionBuildBtn.on('pointerover', () => {
-      if (this.activeCategory !== 'build') this.actionBuildBtn.setFillStyle(0x2a5a2a, 0.9)
+      if (this.activeCategory !== 'build') this.actionBuildBtn.setFillStyle(0x2a5a2a, this.uiOpacity)
     })
     this.actionBuildBtn.on('pointerout', () => {
-      if (this.activeCategory !== 'build') this.actionBuildBtn.setFillStyle(0x1a3a1a, 0.9)
+      if (this.activeCategory !== 'build') this.actionBuildBtn.setFillStyle(0x1a3a1a, this.uiOpacity)
     })
     this.actionBuildBtn.on('pointerdown', () => this.toggleCategory('build'))
 
@@ -1183,27 +1210,41 @@ export class UIScene extends Phaser.Scene {
       fontSize: '12px', color: '#cccccc', fontFamily: 'monospace',
     }).setOrigin(0.5, 0.5).setScrollFactor(0).setDepth(302)
 
-    this.actionNisseBtn = this.add.rectangle(104, barY + 8, 88, 32, 0x1a1a3a, 0.9)
+    this.actionNisseBtn = this.add.rectangle(104, barY + 8, 88, 32, 0x1a1a3a, this.uiOpacity)
       .setOrigin(0, 0).setScrollFactor(0).setDepth(301).setInteractive()
     this.actionNisseBtn.on('pointerover', () => {
-      if (this.activeCategory !== 'nisse') this.actionNisseBtn.setFillStyle(0x2a2a5a, 0.9)
+      if (this.activeCategory !== 'nisse') this.actionNisseBtn.setFillStyle(0x2a2a5a, this.uiOpacity)
     })
     this.actionNisseBtn.on('pointerout', () => {
-      if (this.activeCategory !== 'nisse') this.actionNisseBtn.setFillStyle(0x1a1a3a, 0.9)
+      if (this.activeCategory !== 'nisse') this.actionNisseBtn.setFillStyle(0x1a1a3a, this.uiOpacity)
     })
     this.actionNisseBtn.on('pointerdown', () => this.toggleCategory('nisse'))
 
     this.actionNisseLabel = this.add.text(148, barY + UIScene.BAR_H / 2, '👥 Nisse', {
       fontSize: '12px', color: '#cccccc', fontFamily: 'monospace',
     }).setOrigin(0.5, 0.5).setScrollFactor(0).setDepth(302)
+
+    this.actionDemolishBtn = this.add.rectangle(200, barY + 8, 88, 32, 0x3a1a1a, this.uiOpacity)
+      .setOrigin(0, 0).setScrollFactor(0).setDepth(301).setInteractive()
+    this.actionDemolishBtn.on('pointerover', () => {
+      if (this.activeCategory !== 'demolish') this.actionDemolishBtn.setFillStyle(0x5a2a2a, this.uiOpacity)
+    })
+    this.actionDemolishBtn.on('pointerout', () => {
+      if (this.activeCategory !== 'demolish') this.actionDemolishBtn.setFillStyle(0x3a1a1a, this.uiOpacity)
+    })
+    this.actionDemolishBtn.on('pointerdown', () => this.toggleCategory('demolish'))
+
+    this.actionDemolishLabel = this.add.text(244, barY + UIScene.BAR_H / 2, '💥 Demolish', {
+      fontSize: '12px', color: '#cccccc', fontFamily: 'monospace',
+    }).setOrigin(0.5, 0.5).setScrollFactor(0).setDepth(302)
   }
 
   /**
    * Toggles the given action bar category on or off.
    * Selecting the active category deselects it; selecting a new one closes the previous.
-   * @param cat - The category to toggle ('build' or 'nisse')
+   * @param cat - The category to toggle
    */
-  private toggleCategory(cat: 'build' | 'nisse'): void {
+  private toggleCategory(cat: 'build' | 'nisse' | 'demolish'): void {
     if (this.activeCategory === cat) {
       this.deactivateCategory()
       return
@@ -1211,14 +1252,17 @@ export class UIScene extends Phaser.Scene {
     // Close whatever was open before
     if (this.activeCategory === 'build') this.closeActionTray()
     if (this.activeCategory === 'nisse' && this.villagerPanelVisible) this.closeVillagerPanel()
+    if (this.activeCategory === 'demolish') this.scene.get('Game').events.emit('deactivateDemolish')
 
     this.activeCategory = cat
     this.updateCategoryHighlights()
 
     if (cat === 'build') {
       this.openActionTray()
-    } else {
+    } else if (cat === 'nisse') {
       this.openVillagerPanel()
+    } else {
+      this.scene.get('Game').events.emit('activateDemolish')
     }
   }
 
@@ -1228,17 +1272,19 @@ export class UIScene extends Phaser.Scene {
   private deactivateCategory(): void {
     if (this.activeCategory === 'build') this.closeActionTray()
     if (this.activeCategory === 'nisse' && this.villagerPanelVisible) this.closeVillagerPanel()
+    if (this.activeCategory === 'demolish') this.scene.get('Game').events.emit('deactivateDemolish')
     this.activeCategory = null
     this.updateCategoryHighlights()
   }
 
   /**
-   * Updates the visual highlight of the Build and Nisse buttons
+   * Updates the visual highlight of the Build, Nisse, and Demolish buttons
    * to reflect the current active category.
    */
   private updateCategoryHighlights(): void {
-    this.actionBuildBtn.setFillStyle(this.activeCategory === 'build' ? 0x3d7a3d : 0x1a3a1a, 0.9)
+    this.actionBuildBtn.setFillStyle(this.activeCategory === 'build' ? 0x3d7a3d : 0x1a3a1a, this.uiOpacity)
-    this.actionNisseBtn.setFillStyle(this.activeCategory === 'nisse' ? 0x3d3d7a : 0x1a1a3a, 0.9)
+    this.actionNisseBtn.setFillStyle(this.activeCategory === 'nisse' ? 0x3d3d7a : 0x1a1a3a, this.uiOpacity)
+    this.actionDemolishBtn.setFillStyle(this.activeCategory === 'demolish' ? 0x7a3d3d : 0x3a1a1a, this.uiOpacity)
   }
 
   /**
@@ -1250,12 +1296,13 @@ export class UIScene extends Phaser.Scene {
     this.actionTrayVisible = true
     this.actionTrayGroup.destroy(true)
     this.actionTrayGroup = this.add.group()
+    this.actionBarBg.setAlpha(0)
 
     const { width, height } = this.scale
     const trayY = height - UIScene.BAR_H - UIScene.TRAY_H
 
-    const bg = this.add.rectangle(0, trayY, width, UIScene.TRAY_H, 0x0d0d0d, 0.88)
+    const bg = this.add.rectangle(0, trayY, width, UIScene.TRAY_H + UIScene.BAR_H, 0x080808, this.uiOpacity)
-      .setOrigin(0, 0).setScrollFactor(0).setDepth(300)
+      .setOrigin(0, 0).setScrollFactor(0).setDepth(299)
     this.actionTrayGroup.add(bg)
 
     const buildings: { kind: BuildingType; emoji: string; label: string }[] = [
@@ -1265,15 +1312,16 @@ export class UIScene extends Phaser.Scene {
       { kind: 'bed',            emoji: '🛏',  label: 'Bed'         },
       { kind: 'stockpile_zone', emoji: '📦', label: 'Stockpile'  },
       { kind: 'forester_hut',   emoji: '🌲', label: 'Forester'   },
+      { kind: 'mine',           emoji: '⛏',  label: 'Mine'        },
     ]
 
     const itemW = 84
     buildings.forEach((b, i) => {
       const bx = 8 + i * (itemW + 4)
-      const btn = this.add.rectangle(bx, trayY + 4, itemW, UIScene.TRAY_H - 8, 0x1a2a1a, 0.9)
+      const btn = this.add.rectangle(bx, trayY + 4, itemW, UIScene.TRAY_H - 8, 0x1a2a1a, this.uiOpacity)
         .setOrigin(0, 0).setScrollFactor(0).setDepth(301).setInteractive()
-      btn.on('pointerover', () => btn.setFillStyle(0x2d4a2d, 0.9))
+      btn.on('pointerover', () => btn.setFillStyle(0x2d4a2d, this.uiOpacity))
-      btn.on('pointerout',  () => btn.setFillStyle(0x1a2a1a, 0.9))
+      btn.on('pointerout',  () => btn.setFillStyle(0x1a2a1a, this.uiOpacity))
       btn.on('pointerdown', () => {
         this.closeActionTray()
         this.deactivateCategory()
@@ -1300,6 +1348,7 @@ export class UIScene extends Phaser.Scene {
     this.actionTrayVisible = false
     this.actionTrayGroup.destroy(true)
     this.actionTrayGroup = this.add.group()
+    this.actionBarBg.setAlpha(1)
   }
 
   // ─── Resize ───────────────────────────────────────────────────────────────
@@ -1330,7 +1379,9 @@ export class UIScene extends Phaser.Scene {
     this.actionBuildBtn.setPosition(8,   height - UIScene.BAR_H + 8)
     this.actionBuildLabel.setPosition(48, height - UIScene.BAR_H + UIScene.BAR_H / 2)
     this.actionNisseBtn.setPosition(104, height - UIScene.BAR_H + 8)
-    this.actionNisseLabel.setPosition(144, height - UIScene.BAR_H + UIScene.BAR_H / 2)
+    this.actionNisseLabel.setPosition(148, height - UIScene.BAR_H + UIScene.BAR_H / 2)
+    this.actionDemolishBtn.setPosition(200, height - UIScene.BAR_H + 8)
+    this.actionDemolishLabel.setPosition(244, height - UIScene.BAR_H + UIScene.BAR_H / 2)
     if (this.actionTrayVisible) this.closeActionTray()
     // Close centered panels — their position is calculated on open, so they
     // would be off-center if left open during a resize

src/systems/BuildingSystem.ts

@@ -1,7 +1,7 @@
 import Phaser from 'phaser'
-import { TILE_SIZE, BUILDING_COSTS } from '../config'
+import { TILE_SIZE, BUILDING_COSTS, DEMOLISH_REFUND_MS } from '../config'
 import { TileType, IMPASSABLE } from '../types'
-import type { BuildingType } from '../types'
+import type { BuildingType, BuildingState, ItemId } from '../types'
 import { stateManager } from '../StateManager'
 import type { LocalAdapter } from '../NetworkAdapter'
 
@@ -12,10 +12,18 @@ const BUILDING_TILE: Partial<Record<BuildingType, TileType>> = {
   // bed and stockpile_zone do NOT change the underlying tile
 }
 
+/** Tile type to restore when a building that changed its tile is demolished. */
+const DEMOLISH_RESTORE_TILE: Partial<Record<BuildingType, TileType>> = {
+  floor: TileType.GRASS,
+  wall:  TileType.GRASS,
+  chest: TileType.GRASS,
+}
+
 export class BuildingSystem {
   private scene: Phaser.Scene
   private adapter: LocalAdapter
   private active = false
+  private demolishActive = false
   private selectedBuilding: BuildingType = 'floor'
   private ghost!: Phaser.GameObjects.Rectangle
   private ghostLabel!: Phaser.GameObjects.Text
@@ -24,15 +32,26 @@ export class BuildingSystem {
 
   onModeChange?: (active: boolean, building: BuildingType) => void
   onPlaced?: (msg: string) => void
+  onDemolishModeChange?: (active: boolean) => void
+  /**
+   * Called after a building is demolished with the removed building data and the refund items.
+   * @param building - The BuildingState that was removed
+   * @param refund   - Items returned to stockpile
+   */
+  onDemolished?: (building: BuildingState, refund: Partial<Record<ItemId, number>>) => void
 
   constructor(scene: Phaser.Scene, adapter: LocalAdapter) {
     this.scene = scene
     this.adapter = adapter
   }
 
+  /**
+   * Initialises ghost sprite, label, and keyboard/pointer handlers for
+   * both build mode and demolish mode.
+   */
   create(): void {
     this.ghost = this.scene.add.rectangle(0, 0, TILE_SIZE, TILE_SIZE, 0x00FF00, 0.35)
-    this.ghost.setDepth(20)
+    this.ghost.setDepth(1000)
     this.ghost.setVisible(false)
     this.ghost.setStrokeStyle(2, 0x00FF00, 0.8)
 
@@ -40,27 +59,71 @@ export class BuildingSystem {
       fontSize: '10px', color: '#ffffff', fontFamily: 'monospace',
       backgroundColor: '#000000aa', padding: { x: 3, y: 2 }
     })
-    this.ghostLabel.setDepth(21)
+    this.ghostLabel.setDepth(1001)
     this.ghostLabel.setVisible(false)
     this.ghostLabel.setOrigin(0.5, 1)
 
     this.buildKey  = this.scene.input.keyboard!.addKey(Phaser.Input.Keyboard.KeyCodes.B)
     this.cancelKey = this.scene.input.keyboard!.addKey(Phaser.Input.Keyboard.KeyCodes.ESC)
 
-    // Click to place
+    // Click to place (build mode) or demolish (demolish mode)
     this.scene.input.on('pointerdown', (ptr: Phaser.Input.Pointer) => {
-      if (!this.active) return
       if (ptr.rightButtonDown()) {
-        this.deactivate()
+        if (this.active) this.deactivate()
+        if (this.demolishActive) this.deactivateDemolish()
         return
       }
-      this.tryPlace(ptr)
+      if (this.active) this.tryPlace(ptr)
+      else if (this.demolishActive) this.tryDemolish(ptr)
     })
   }
 
+  /**
+   * Returns the tile footprint dimensions for the given building type.
+   * @param kind - The building type to query
+   * @returns Width and height in tiles
+   */
+  private getFootprint(kind: BuildingType): { w: number; h: number } {
+    if (kind === 'mine') return { w: 3, h: 2 }
+    return { w: 1, h: 1 }
+  }
+
+  /**
+   * Returns all tile positions occupied by the given building,
+   * expanding multi-tile buildings (e.g. mine: 3×2) to their full footprint.
+   * @param b - The building state to expand
+   * @returns Array of tile positions in the building's footprint
+   */
+  private getBuildingFootprintTiles(b: BuildingState): Array<{ tileX: number; tileY: number }> {
+    if (b.kind === 'mine') {
+      const result: Array<{ tileX: number; tileY: number }> = []
+      for (let dy = 0; dy < 2; dy++)
+        for (let dx = 0; dx < 3; dx++)
+          result.push({ tileX: b.tileX + dx, tileY: b.tileY + dy })
+      return result
+    }
+    return [{ tileX: b.tileX, tileY: b.tileY }]
+  }
+
+  /**
+   * Finds the building whose footprint contains the given tile, if any.
+   * @param tileX - Tile column to check
+   * @param tileY - Tile row to check
+   * @returns The matching BuildingState, or undefined
+   */
+  private findBuildingAtTile(tileX: number, tileY: number): BuildingState | undefined {
+    const buildings = Object.values(stateManager.getState().world.buildings)
+    return buildings.find(b =>
+      this.getBuildingFootprintTiles(b).some(t => t.tileX === tileX && t.tileY === tileY)
+    )
+  }
+
   /** Select a building type and activate build mode */
   selectBuilding(kind: BuildingType): void {
+    if (this.demolishActive) this.deactivateDemolish()
     this.selectedBuilding = kind
+    const { w, h } = this.getFootprint(kind)
+    this.ghost.setSize(w * TILE_SIZE, h * TILE_SIZE)
     this.activate()
   }
 
@@ -80,6 +143,37 @@ export class BuildingSystem {
 
   isActive(): boolean { return this.active }
 
+  /**
+   * Activates demolish mode. Deactivates build mode if currently active.
+   * In demolish mode the ghost turns red and clicking a building removes it.
+   */
+  activateDemolish(): void {
+    if (this.active) this.deactivate()
+    this.demolishActive = true
+    this.ghost.setSize(TILE_SIZE, TILE_SIZE)
+    this.ghost.setFillStyle(0xFF2222, 0.35)
+    this.ghost.setStrokeStyle(2, 0xFF2222, 0.9)
+    this.ghost.setVisible(true)
+    this.ghostLabel.setVisible(true)
+    this.onDemolishModeChange?.(true)
+  }
+
+  /**
+   * Deactivates demolish mode and hides the ghost.
+   */
+  deactivateDemolish(): void {
+    this.demolishActive = false
+    this.ghost.setVisible(false)
+    this.ghostLabel.setVisible(false)
+    this.onDemolishModeChange?.(false)
+  }
+
+  /** Returns true if demolish mode is currently active. */
+  isDemolishActive(): boolean { return this.demolishActive }
+
+  /**
+   * Updates ghost position and label each frame for both build and demolish modes.
+   */
   update(): void {
     if (Phaser.Input.Keyboard.JustDown(this.buildKey)) {
       if (this.active) this.deactivate()
@@ -87,23 +181,30 @@ export class BuildingSystem {
     }
     if (Phaser.Input.Keyboard.JustDown(this.cancelKey)) {
       this.deactivate()
+      this.deactivateDemolish()
     }
 
-    if (!this.active) return
+    if (this.active) {
+      this.updateBuildGhost()
+    } else if (this.demolishActive) {
+      this.updateDemolishGhost()
+    }
+  }
 
-    // Update ghost to follow mouse (snapped to tile grid)
+  /**
+   * Updates the green/red build-mode ghost to follow the mouse, snapped to the tile grid.
+   */
+  private updateBuildGhost(): void {
     const ptr    = this.scene.input.activePointer
-    const worldX = ptr.worldX
+    const tileX = Math.floor(ptr.worldX / TILE_SIZE)
-    const worldY = ptr.worldY
+    const tileY = Math.floor(ptr.worldY / TILE_SIZE)
-    const tileX = Math.floor(worldX / TILE_SIZE)
+    const { w, h } = this.getFootprint(this.selectedBuilding)
-    const tileY = Math.floor(worldY / TILE_SIZE)
+    const snapX = tileX * TILE_SIZE + (w * TILE_SIZE) / 2
-    const snapX = tileX * TILE_SIZE + TILE_SIZE / 2
+    const snapY = tileY * TILE_SIZE + (h * TILE_SIZE) / 2
-    const snapY = tileY * TILE_SIZE + TILE_SIZE / 2
 
     this.ghost.setPosition(snapX, snapY)
-    this.ghostLabel.setPosition(snapX, snapY - TILE_SIZE / 2 - 2)
+    this.ghostLabel.setPosition(snapX, snapY - (h * TILE_SIZE) / 2 - 2)
 
-    // Color ghost based on can-build
     const canBuild = this.canBuildAt(tileX, tileY)
     const color = canBuild ? 0x00FF00 : 0xFF4444
     this.ghost.setFillStyle(color, 0.35)
@@ -114,8 +215,62 @@ export class BuildingSystem {
     this.ghostLabel.setText(`${this.selectedBuilding} [${costStr}]`)
   }
 
+  /**
+   * Updates the red demolish ghost to follow the mouse. Highlights the hovered building's
+   * footprint and shows the refund percentage in the label.
+   */
+  private updateDemolishGhost(): void {
+    const ptr   = this.scene.input.activePointer
+    const tileX = Math.floor(ptr.worldX / TILE_SIZE)
+    const tileY = Math.floor(ptr.worldY / TILE_SIZE)
+
+    const building = this.findBuildingAtTile(tileX, tileY)
+    if (building) {
+      const { w, h } = this.getFootprint(building.kind)
+      const snapX = building.tileX * TILE_SIZE + (w * TILE_SIZE) / 2
+      const snapY = building.tileY * TILE_SIZE + (h * TILE_SIZE) / 2
+      this.ghost.setSize(w * TILE_SIZE, h * TILE_SIZE)
+      this.ghost.setPosition(snapX, snapY)
+      this.ghostLabel.setPosition(snapX, snapY - (h * TILE_SIZE) / 2 - 2)
+      this.ghost.setFillStyle(0xFF2222, 0.45)
+      this.ghost.setStrokeStyle(2, 0xFF2222, 1)
+
+      const refundPct = this.calcRefundPct(building)
+      const label = refundPct > 0
+        ? `${building.kind} [refund ${Math.round(refundPct * 100)}%]`
+        : `${building.kind} [no refund]`
+      this.ghostLabel.setText(label)
+    } else {
+      // No building under cursor — small neutral ghost
+      const snapX = tileX * TILE_SIZE + TILE_SIZE / 2
+      const snapY = tileY * TILE_SIZE + TILE_SIZE / 2
+      this.ghost.setSize(TILE_SIZE, TILE_SIZE)
+      this.ghost.setPosition(snapX, snapY)
+      this.ghostLabel.setPosition(snapX, snapY - TILE_SIZE / 2 - 2)
+      this.ghost.setFillStyle(0x444444, 0.2)
+      this.ghost.setStrokeStyle(1, 0x666666, 0.5)
+      this.ghostLabel.setText('')
+    }
+  }
+
+  /**
+   * Calculates the refund fraction (0–1) for a building based on how long ago it was built.
+   * Returns 1.0 within the first 3 minutes, decaying linearly to 0.
+   * @param building - The building to evaluate
+   * @returns Refund fraction between 0 and 1
+   */
+  private calcRefundPct(building: BuildingState): number {
+    const elapsed = stateManager.getGameTime() - (building.builtAt ?? 0)
+    return Math.max(0, 1 - elapsed / DEMOLISH_REFUND_MS)
+  }
+
   private canBuildAt(tileX: number, tileY: number): boolean {
     const state = stateManager.getState()
+
+    if (this.selectedBuilding === 'mine') {
+      return this.canPlaceMineAt(tileX, tileY)
+    }
+
     const tile = state.world.tiles[tileY * 512 + tileX] as TileType  // 512 = WORLD_TILES
 
     // Can only build on passable ground tiles (not water, not existing buildings)
@@ -141,6 +296,40 @@ export class BuildingSystem {
     return true
   }
 
+  /**
+   * Checks whether a 3×2 mine can be placed with top-left at (tileX, tileY).
+   * All 6 tiles must be ROCK with no resources and no overlapping buildings.
+   * @param tileX - Top-left tile column
+   * @param tileY - Top-left tile row
+   */
+  private canPlaceMineAt(tileX: number, tileY: number): boolean {
+    const state = stateManager.getState()
+
+    // Check costs
+    const costs = BUILDING_COSTS.mine
+    for (const [item, qty] of Object.entries(costs)) {
+      const have = state.world.stockpile[item as keyof typeof state.world.stockpile] ?? 0
+      if (have < qty) return false
+    }
+
+    const resources = Object.values(state.world.resources)
+    const buildings = Object.values(state.world.buildings)
+
+    for (let dy = 0; dy < 2; dy++) {
+      for (let dx = 0; dx < 3; dx++) {
+        const tx = tileX + dx, ty = tileY + dy
+        // Must be ROCK
+        if ((state.world.tiles[ty * 512 + tx] as TileType) !== TileType.ROCK) return false
+        // No resource on this tile
+        if (resources.some(r => r.tileX === tx && r.tileY === ty)) return false
+        // No existing building footprint overlapping this tile
+        if (buildings.some(b => this.getBuildingFootprintTiles(b).some(t => t.tileX === tx && t.tileY === ty))) return false
+      }
+    }
+
+    return true
+  }
+
   private tryPlace(ptr: Phaser.Input.Pointer): void {
     const worldX = ptr.worldX
     const worldY = ptr.worldY
@@ -148,33 +337,92 @@ export class BuildingSystem {
     const tileY = Math.floor(worldY / TILE_SIZE)
 
     if (!this.canBuildAt(tileX, tileY)) {
-      this.onPlaced?.('Cannot build here!')
+      const missing = this.getMissingResources(tileX, tileY)
+      this.onPlaced?.(missing.length ? `Need: ${missing}` : 'Cannot build here!')
       return
     }
 
     const costs = BUILDING_COSTS[this.selectedBuilding] ?? {}
-    const building = {
+    const building: BuildingState = {
       id: `building_${tileX}_${tileY}_${Date.now()}`,
       tileX,
       tileY,
       kind: this.selectedBuilding,
       ownerId: stateManager.getState().player.id,
+      builtAt: stateManager.getGameTime(),
     }
 
     this.adapter.send({ type: 'PLACE_BUILDING', building, costs })
-    // Only change the tile type for buildings that have a floor/wall tile mapping
+    // Mine keeps its ROCK tile type; footprint blocking is handled in renderPersistentObjects.
-    const tileMapped = BUILDING_TILE[this.selectedBuilding]
+    // Other buildings change tile type where applicable.
-    if (tileMapped !== undefined) {
+    if (this.selectedBuilding !== 'mine') {
-      this.adapter.send({
+      const tileMapped = BUILDING_TILE[this.selectedBuilding]
-        type: 'CHANGE_TILE',
+      if (tileMapped !== undefined) {
-        tileX,
+        this.adapter.send({ type: 'CHANGE_TILE', tileX, tileY, tile: tileMapped })
-        tileY,
+      }
-        tile: tileMapped,
-      })
     }
     this.onPlaced?.(`Placed ${this.selectedBuilding}!`)
   }
 
+  /**
+   * Returns a human-readable string describing which resources are missing
+   * to build the currently selected building at the given tile.
+   * @param tileX - Tile column
+   * @param tileY - Tile row
+   * @returns Comma-separated missing resource string, or empty string if nothing is missing
+   */
+  private getMissingResources(tileX: number, tileY: number): string {
+    const state = stateManager.getState()
+    const costs = BUILDING_COSTS[this.selectedBuilding] ?? {}
+    const parts: string[] = []
+    for (const [item, qty] of Object.entries(costs)) {
+      const have = state.world.stockpile[item as keyof typeof state.world.stockpile] ?? 0
+      if (have < qty) parts.push(`${qty - have} ${item}`)
+    }
+    return parts.join(', ')
+  }
+
+  /**
+   * Attempts to demolish the building at the clicked tile.
+   * Calculates the time-based refund, removes the building from state,
+   * restores the tile type if applicable, and fires onDemolished.
+   * @param ptr - The pointer that was clicked
+   */
+  private tryDemolish(ptr: Phaser.Input.Pointer): void {
+    const tileX = Math.floor(ptr.worldX / TILE_SIZE)
+    const tileY = Math.floor(ptr.worldY / TILE_SIZE)
+
+    const building = this.findBuildingAtTile(tileX, tileY)
+    if (!building) return
+
+    // Calculate refund
+    const costs = BUILDING_COSTS[building.kind] ?? {}
+    const refundPct = this.calcRefundPct(building)
+    const refund: Partial<Record<ItemId, number>> = {}
+    for (const [item, qty] of Object.entries(costs)) {
+      const amount = Math.floor((qty ?? 0) * refundPct)
+      if (amount > 0) refund[item as ItemId] = amount
+    }
+
+    this.adapter.send({ type: 'REMOVE_BUILDING', buildingId: building.id })
+
+    // Restore tile type for buildings that changed it on placement
+    const restoreTile = DEMOLISH_RESTORE_TILE[building.kind]
+    if (restoreTile !== undefined) {
+      this.adapter.send({ type: 'CHANGE_TILE', tileX: building.tileX, tileY: building.tileY, tile: restoreTile })
+    }
+
+    // Return resources to stockpile
+    if (Object.keys(refund).length > 0) {
+      this.adapter.send({ type: 'ADD_ITEMS', items: refund })
+    }
+
+    this.onDemolished?.(building, refund)
+  }
+
+  /**
+   * Cleans up ghost sprites on scene shutdown.
+   */
   destroy(): void {
     this.ghost.destroy()
     this.ghostLabel.destroy()

src/systems/DebugSystem.ts

@@ -2,6 +2,7 @@ import Phaser from 'phaser'
 import { TILE_SIZE } from '../config'
 import { TileType } from '../types'
 import { stateManager } from '../StateManager'
+import type { LocalAdapter } from '../NetworkAdapter'
 import type { VillagerSystem } from './VillagerSystem'
 import type { WorldSystem } from './WorldSystem'
 
@@ -18,6 +19,8 @@ export interface DebugData {
   nisseByState: { idle: number; walking: number; working: number; sleeping: number }
   jobsByType:   { chop: number; mine: number; farm: number }
   activePaths:  number
+  /** Recent actions dispatched through the adapter (newest last). */
+  actionLog: readonly string[]
 }
 
 /** Human-readable names for TileType enum values. */
@@ -39,6 +42,7 @@ export class DebugSystem {
   private scene:          Phaser.Scene
   private villagerSystem: VillagerSystem
   private worldSystem:    WorldSystem
+  private adapter:        LocalAdapter
   private pathGraphics!:  Phaser.GameObjects.Graphics
   private active = false
 
@@ -46,11 +50,13 @@ export class DebugSystem {
    * @param scene          - The Phaser scene this system belongs to
    * @param villagerSystem - Used to read active paths for visualization
    * @param worldSystem    - Used to read tile types under the mouse
+   * @param adapter        - Used to read the recent action log
    */
-  constructor(scene: Phaser.Scene, villagerSystem: VillagerSystem, worldSystem: WorldSystem) {
+  constructor(scene: Phaser.Scene, villagerSystem: VillagerSystem, worldSystem: WorldSystem, adapter: LocalAdapter) {
     this.scene          = scene
     this.villagerSystem = villagerSystem
     this.worldSystem    = worldSystem
+    this.adapter        = adapter
   }
 
   /**
@@ -159,6 +165,7 @@ export class DebugSystem {
       nisseByState,
       jobsByType,
       activePaths:    this.villagerSystem.getActivePaths().length,
+      actionLog:      this.adapter.getActionLog(),
     }
   }
 }

src/systems/FarmingSystem.ts

@@ -74,8 +74,8 @@ export class FarmingSystem {
       this.setTool(TOOL_CYCLE[(idx + 1) % TOOL_CYCLE.length])
     }
 
-    // Tick crop growth
+    // Drain crop growth queue (no delta — gameTime is advanced by GameScene)
-    const leveled = stateManager.tickCrops(delta)
+    const leveled = stateManager.tickCrops()
     for (const id of leveled) this.refreshCropSprite(id)
   }
 
@@ -151,11 +151,13 @@ export class FarmingSystem {
     }
 
     const cfg = CROP_CONFIGS[kind]
+    const now = stateManager.getGameTime()
     const crop: CropState = {
       id: `crop_${tileX}_${tileY}_${Date.now()}`,
       tileX, tileY, kind,
       stage: 0, maxStage: cfg.stages,
-      stageTimerMs: cfg.stageTimeMs,
+      growsAt:        now + cfg.stageTimeMs,
+      growsAtWatered: now + cfg.stageTimeMs / 2,
       watered: tile === TileType.WATERED_SOIL,
     }
     this.adapter.send({ type: 'PLANT_CROP', crop, seedItem })

src/systems/ResourceSystem.ts

@@ -47,10 +47,10 @@ export class ResourceSystem {
       sprite.setOrigin(0.5, 0.75)
     }
 
-    sprite.setDepth(5)
+    sprite.setDepth(node.tileY + 5)
 
     const healthBar = this.scene.add.graphics()
-    healthBar.setDepth(6)
+    healthBar.setDepth(node.tileY + 6)
     healthBar.setVisible(false)
 
     this.sprites.set(node.id, { sprite, node, healthBar })

src/systems/TreeSeedlingSystem.ts

@@ -38,7 +38,8 @@ export class TreeSeedlingSystem {
    * @param delta - Frame delta in milliseconds
    */
   update(delta: number): void {
-    const advanced = stateManager.tickSeedlings(delta)
+    // Drain seedling growth queue (no delta — gameTime is advanced by GameScene)
+    const advanced = stateManager.tickSeedlings()
     for (const id of advanced) {
       const state = stateManager.getState()
       const seedling = state.world.treeSeedlings[id]
@@ -91,7 +92,7 @@ export class TreeSeedlingSystem {
     const seedling: TreeSeedlingState = {
       id, tileX, tileY,
       stage: 0,
-      stageTimerMs: TREE_SEEDLING_STAGE_MS,
+      growsAt: stateManager.getGameTime() + TREE_SEEDLING_STAGE_MS,
       underlyingTile,
     }
 
@@ -110,7 +111,7 @@ export class TreeSeedlingSystem {
     const key = `seedling_${Math.min(s.stage, 2)}`
     const sprite = this.scene.add.image(x, y, key)
       .setOrigin(0.5, 0.85)
-      .setDepth(5)
+      .setDepth(s.tileY + 5)
     this.sprites.set(s.id, sprite)
   }
 

src/systems/VillagerSystem.ts

@@ -1,5 +1,5 @@
 import Phaser from 'phaser'
-import { TILE_SIZE, VILLAGER_SPEED, VILLAGER_SPAWN_INTERVAL, VILLAGER_WORK_TIMES, VILLAGER_NAMES, WORLD_TILES } from '../config'
+import { TILE_SIZE, VILLAGER_SPEED, VILLAGER_SPAWN_INTERVAL, VILLAGER_WORK_TIMES, VILLAGER_NAMES, WORLD_TILES, MINE_CAPACITY, MINE_WORK_MS, MINE_STONE_YIELD } from '../config'
 import { TileType, PLANTABLE_TILES } from '../types'
 import type { VillagerState, VillagerJob, JobType, AIState, ItemId } from '../types'
 import { stateManager } from '../StateManager'
@@ -13,6 +13,9 @@ const ARRIVAL_PX = 3
 
 const WORK_LOG_MAX = 20
 
+/** Job-type → display icon mapping; defined once at module level to avoid per-frame allocation. */
+const JOB_ICONS: Record<string, string> = { chop: '🪓', mine: '⛏', farm: '🌾', forester: '🌲', '': '' }
+
 interface VillagerRuntime {
   sprite: Phaser.GameObjects.Image
   nameLabel: Phaser.GameObjects.Text
@@ -34,7 +37,8 @@ export class VillagerSystem {
   private farmingSystem!: FarmingSystem
 
   private runtime = new Map<string, VillagerRuntime>()
-  private claimed = new Set<string>()   // target IDs currently claimed by a villager
+  private claimed = new Set<string>()           // target IDs currently claimed (resources, crops, etc.)
+  private mineClaimsMap = new Map<string, number>()  // mine building ID → number of claimed slots
   private spawnTimer = 0
   private nameIndex = 0
 
@@ -69,6 +73,48 @@ export class VillagerSystem {
     this.farmingSystem  = farmingSystem
   }
 
+  // ─── Claim helpers ────────────────────────────────────────────────────────
+
+  /**
+   * Claims a job target. Mine buildings use a capacity counter (up to MINE_CAPACITY);
+   * all other targets use the exclusive claimed Set.
+   * @param targetId - The resource, crop, or building ID being claimed
+   */
+  private claimTarget(targetId: string): void {
+    if (stateManager.getState().world.buildings[targetId]?.kind === 'mine') {
+      this.mineClaimsMap.set(targetId, (this.mineClaimsMap.get(targetId) ?? 0) + 1)
+    } else {
+      this.claimed.add(targetId)
+    }
+  }
+
+  /**
+   * Releases a job target claim.
+   * @param targetId - The previously claimed target ID
+   */
+  private releaseTarget(targetId: string): void {
+    if (stateManager.getState().world.buildings[targetId]?.kind === 'mine') {
+      const n = this.mineClaimsMap.get(targetId) ?? 0
+      if (n <= 1) this.mineClaimsMap.delete(targetId)
+      else this.mineClaimsMap.set(targetId, n - 1)
+    } else {
+      this.claimed.delete(targetId)
+    }
+  }
+
+  /**
+   * Returns true if the given target is fully claimed.
+   * Mine buildings are claimed when their worker count reaches MINE_CAPACITY.
+   * All other targets are claimed exclusively.
+   * @param targetId - The target ID to check
+   */
+  private isTargetClaimed(targetId: string): boolean {
+    if (stateManager.getState().world.buildings[targetId]?.kind === 'mine') {
+      return (this.mineClaimsMap.get(targetId) ?? 0) >= MINE_CAPACITY
+    }
+    return this.claimed.has(targetId)
+  }
+
   /**
    * Spawns sprites for all Nisse that exist in the saved state
    * and re-claims any active job targets.
@@ -78,7 +124,7 @@ export class VillagerSystem {
     for (const v of Object.values(state.world.villagers)) {
       this.spawnSprite(v)
       // Re-claim any active job targets
-      if (v.job) this.claimed.add(v.job.targetId)
+      if (v.job) this.claimTarget(v.job.targetId)
     }
   }
 
@@ -118,15 +164,15 @@ export class VillagerSystem {
       case 'sleeping':this.tickSleeping(v, rt, delta);      break
     }
 
-    // Sync sprite to state position
+    // Nisse always render above world objects
     rt.sprite.setPosition(v.x, v.y)
+
     rt.nameLabel.setPosition(v.x, v.y - 22)
     rt.energyBar.setPosition(0, 0)
     this.drawEnergyBar(rt.energyBar, v.x, v.y, v.energy)
 
     // Job icon
-    const icons: Record<string, string> = { chop: '🪓', mine: '⛏', farm: '🌾', forester: '🌲', '': '' }
+    const jobType = v.aiState === 'sleeping' ? '💤' : (v.job ? (JOB_ICONS[v.job.type] ?? '') : '')
-    const jobType = v.aiState === 'sleeping' ? '💤' : (v.job ? (icons[v.job.type] ?? '') : '')
     rt.jobIcon.setText(jobType).setPosition(v.x + 10, v.y - 18)
   }
 
@@ -170,7 +216,7 @@ export class VillagerSystem {
     // Find a job
     const job = this.pickJob(v)
     if (job) {
-      this.claimed.add(job.targetId)
+      this.claimTarget(job.targetId)
       this.adapter.send({
         type: 'VILLAGER_SET_JOB', villagerId: v.id,
         job: { type: job.type, targetId: job.targetId, tileX: job.tileX, tileY: job.tileY, carrying: {} },
@@ -229,10 +275,20 @@ export class VillagerSystem {
    */
   private onArrived(v: VillagerState, rt: VillagerRuntime): void {
     switch (rt.destination) {
-      case 'job':
+      case 'job': {
-        rt.workTimer = VILLAGER_WORK_TIMES[v.job?.type ?? 'chop'] ?? 3000
+        // Mine buildings take longer than surface-rock mining and hide the Nisse sprite.
+        const isMineBuilding = v.job?.type === 'mine' &&
+          stateManager.getState().world.buildings[v.job.targetId]?.kind === 'mine'
+        rt.workTimer = isMineBuilding ? MINE_WORK_MS : (VILLAGER_WORK_TIMES[v.job?.type ?? 'chop'] ?? 3000)
+        if (isMineBuilding) {
+          rt.sprite.setVisible(false)
+          rt.nameLabel.setVisible(false)
+          rt.energyBar.setVisible(false)
+          rt.jobIcon.setVisible(false)
+        }
         this.adapter.send({ type: 'VILLAGER_SET_AI', villagerId: v.id, aiState: 'working' })
         break
+      }
 
       case 'stockpile':
         this.adapter.send({ type: 'VILLAGER_DEPOSIT', villagerId: v.id })
@@ -273,7 +329,7 @@ export class VillagerSystem {
     const job = v.job
     if (!job) { this.adapter.send({ type: 'VILLAGER_SET_AI', villagerId: v.id, aiState: 'idle' }); return }
 
-    this.claimed.delete(job.targetId)
+    this.releaseTarget(job.targetId)
     const state = stateManager.getState()
 
     if (job.type === 'chop') {
@@ -290,13 +346,27 @@ export class VillagerSystem {
         this.addLog(v.id, `✓ Chopped tree (+2 wood, +${seeds} tree seed)`)
       }
     } else if (job.type === 'mine') {
-      const res = state.world.resources[job.targetId]
+      const building = state.world.buildings[job.targetId]
-      if (res) {
+      if (building?.kind === 'mine') {
-        this.adapter.send({ type: 'VILLAGER_HARVEST_RESOURCE', villagerId: v.id, resourceId: job.targetId })
+        // Mine building: yield stone directly into carrying, then show the Nisse again
-        this.adapter.send({ type: 'CHANGE_TILE', tileX: res.tileX, tileY: res.tileY, tile: TileType.GRASS })
+        const mutableJob = v.job as { carrying: Partial<Record<'stone', number>> }
-        this.worldSystem.removeResourceTile(res.tileX, res.tileY)
+        mutableJob.carrying.stone = (mutableJob.carrying.stone ?? 0) + MINE_STONE_YIELD
-        this.resourceSystem.removeResource(job.targetId)
+        rt.sprite.setVisible(true)
-        this.addLog(v.id, '✓ Mined rock (+2 stone)')
+        rt.nameLabel.setVisible(true)
+        rt.energyBar.setVisible(true)
+        rt.jobIcon.setVisible(true)
+        this.addLog(v.id, `✓ Mined (+${MINE_STONE_YIELD} stone) at mine`)
+      } else {
+        // Surface rock: ROCK tile stays ROCK after mining
+        const res = state.world.resources[job.targetId]
+        if (res) {
+          this.adapter.send({ type: 'VILLAGER_HARVEST_RESOURCE', villagerId: v.id, resourceId: job.targetId })
+          // ROCK tile stays ROCK after mining — empty rocky ground remains passable
+          // and valid for mine building placement.
+          this.worldSystem.removeResourceTile(res.tileX, res.tileY)
+          this.resourceSystem.removeResource(job.targetId)
+          this.addLog(v.id, '✓ Mined rock (+2 stone)')
+        }
       }
     } else if (job.type === 'farm') {
       const crop = state.world.crops[job.targetId]
@@ -376,21 +446,28 @@ export class VillagerSystem {
     const vTY   = Math.floor(v.y / TILE_SIZE)
     const dist  = (tx: number, ty: number) => Math.abs(tx - vTX) + Math.abs(ty - vTY)
 
+    // Extract state collections once — avoids repeated Object.values() allocation per branch/loop.
+    const resources   = Object.values(state.world.resources)
+    const buildings   = Object.values(state.world.buildings)
+    const crops       = Object.values(state.world.crops)
+    const seedlings   = Object.values(state.world.treeSeedlings)
+    const zones       = Object.values(state.world.foresterZones)
+
     type C = { type: JobType; targetId: string; tileX: number; tileY: number; dist: number; pri: number }
     const candidates: C[] = []
 
     if (p.chop > 0) {
       // Build the set of all tiles belonging to forester zones for chop priority
       const zoneTiles = new Set<string>()
-      for (const zone of Object.values(state.world.foresterZones)) {
+      for (const zone of zones) {
         for (const key of zone.tiles) zoneTiles.add(key)
       }
 
       const zoneChop: C[]    = []
       const naturalChop: C[] = []
 
-      for (const res of Object.values(state.world.resources)) {
+      for (const res of resources) {
-        if (res.kind !== 'tree' || this.claimed.has(res.id)) continue
+        if (res.kind !== 'tree' || this.isTargetClaimed(res.id)) continue
         // Skip trees with no reachable neighbour — A* cannot reach them.
         if (!this.hasAdjacentPassable(res.tileX, res.tileY)) continue
         const c: C = { type: 'chop', targetId: res.id, tileX: res.tileX, tileY: res.tileY, dist: dist(res.tileX, res.tileY), pri: p.chop }
@@ -405,8 +482,15 @@ export class VillagerSystem {
     }
 
     if (p.mine > 0) {
-      for (const res of Object.values(state.world.resources)) {
+      // Mine buildings: walk to entrance tile (tileX+1, tileY+1) and work inside
-        if (res.kind !== 'rock' || this.claimed.has(res.id)) continue
+      for (const b of buildings) {
+        if (b.kind !== 'mine' || this.isTargetClaimed(b.id)) continue
+        const eTileX = b.tileX + 1, eTileY = b.tileY + 1
+        candidates.push({ type: 'mine', targetId: b.id, tileX: eTileX, tileY: eTileY, dist: dist(eTileX, eTileY), pri: p.mine })
+      }
+      // Surface rocks (still valid without a mine building)
+      for (const res of resources) {
+        if (res.kind !== 'rock' || this.isTargetClaimed(res.id)) continue
         // Same reachability guard for rock tiles.
         if (!this.hasAdjacentPassable(res.tileX, res.tileY)) continue
         candidates.push({ type: 'mine', targetId: res.id, tileX: res.tileX, tileY: res.tileY, dist: dist(res.tileX, res.tileY), pri: p.mine })
@@ -414,28 +498,28 @@ export class VillagerSystem {
     }
 
     if (p.farm > 0) {
-      for (const crop of Object.values(state.world.crops)) {
+      for (const crop of crops) {
-        if (crop.stage < crop.maxStage || this.claimed.has(crop.id)) continue
+        if (crop.stage < crop.maxStage || this.isTargetClaimed(crop.id)) continue
         candidates.push({ type: 'farm', targetId: crop.id, tileX: crop.tileX, tileY: crop.tileY, dist: dist(crop.tileX, crop.tileY), pri: p.farm })
       }
     }
 
     if (p.forester > 0 && (state.world.stockpile.tree_seed ?? 0) > 0) {
       // Find empty plantable zone tiles to seed
-      for (const zone of Object.values(state.world.foresterZones)) {
+      for (const zone of zones) {
         for (const key of zone.tiles) {
           const [tx, ty] = key.split(',').map(Number)
           const targetId = `forester_tile_${tx}_${ty}`
-          if (this.claimed.has(targetId)) continue
+          if (this.isTargetClaimed(targetId)) continue
           // Skip if tile is not plantable
           const tileType = state.world.tiles[ty * WORLD_TILES + tx] as TileType
           if (!PLANTABLE_TILES.has(tileType)) continue
-          // Skip if something occupies this tile
+          // Skip if something occupies this tile — reuse already-extracted arrays
           const occupied =
-            Object.values(state.world.resources).some(r => r.tileX === tx && r.tileY === ty) ||
+            resources.some(r => r.tileX === tx && r.tileY === ty) ||
-            Object.values(state.world.buildings).some(b => b.tileX === tx && b.tileY === ty) ||
+            buildings.some(b => b.tileX === tx && b.tileY === ty) ||
-            Object.values(state.world.crops).some(c => c.tileX === tx && c.tileY === ty) ||
+            crops.some(c => c.tileX === tx && c.tileY === ty) ||
-            Object.values(state.world.treeSeedlings).some(s => s.tileX === tx && s.tileY === ty)
+            seedlings.some(s => s.tileX === tx && s.tileY === ty)
           if (occupied) continue
           candidates.push({ type: 'forester', targetId, tileX: tx, tileY: ty, dist: dist(tx, ty), pri: p.forester })
         }
@@ -444,8 +528,9 @@ export class VillagerSystem {
 
     if (candidates.length === 0) return null
 
-    // Lowest priority number wins; ties broken by distance
+    // Lowest priority number wins; ties broken by distance — avoid spread+map allocation
-    const bestPri = Math.min(...candidates.map(c => c.pri))
+    let bestPri = candidates[0].pri
+    for (let i = 1; i < candidates.length; i++) if (candidates[i].pri < bestPri) bestPri = candidates[i].pri
     return candidates
       .filter(c => c.pri === bestPri)
       .sort((a, b) => a.dist - b.dist)[0] ?? null
@@ -469,7 +554,7 @@ export class VillagerSystem {
 
     if (!path) {
       if (v.job) {
-        this.claimed.delete(v.job.targetId)
+        this.releaseTarget(v.job.targetId)
         this.adapter.send({ type: 'VILLAGER_SET_JOB', villagerId: v.id, job: null })
       }
       rt.idleScanTimer = 4000  // longer delay after failed pathfind to avoid tight retry loops
@@ -569,16 +654,23 @@ export class VillagerSystem {
    * for a newly added Nisse.
    * @param v - Villager state to create sprites for
    */
+  /**
+   * Creates and registers all runtime objects (sprite, outline, label, energy bar, icon)
+   * for a newly added Nisse.
+   * @param v - Villager state to create sprites for
+   */
   private spawnSprite(v: VillagerState): void {
-    const sprite = this.scene.add.image(v.x, v.y, 'villager').setDepth(11)
+    // Nisse always render above trees, buildings and other world objects.
+    const sprite = this.scene.add.image(v.x, v.y, 'villager')
+      .setDepth(900)
 
     const nameLabel = this.scene.add.text(v.x, v.y - 22, v.name, {
       fontSize: '8px', color: '#ffffff', fontFamily: 'monospace',
       backgroundColor: '#00000088', padding: { x: 2, y: 1 },
-    }).setOrigin(0.5, 1).setDepth(12)
+    }).setOrigin(0.5, 1).setDepth(901)
 
-    const energyBar = this.scene.add.graphics().setDepth(12)
+    const energyBar = this.scene.add.graphics().setDepth(901)
-    const jobIcon   = this.scene.add.text(v.x, v.y - 18, '', { fontSize: '10px' }).setDepth(13)
+    const jobIcon   = this.scene.add.text(v.x, v.y - 18, '', { fontSize: '10px' }).setDepth(902)
 
     sprite.setInteractive()
     sprite.on('pointerdown', () => this.onNisseClick?.(v.id))
@@ -667,6 +759,41 @@ export class VillagerSystem {
     return result
   }
 
+  /**
+   * Destroys all Nisse sprites and clears the runtime map.
+   * Should be called when the scene shuts down.
+   */
+  /**
+   * Destroys all Nisse sprites and clears the runtime map.
+   * Should be called when the scene shuts down.
+   */
+  /**
+   * Rescues all Nisse that were working inside a demolished building.
+   * Makes hidden sprites visible again, clears their jobs, and resets AI to idle.
+   * Also releases any mine-capacity claims for that building.
+   * @param buildingId - ID of the building that was demolished
+   */
+  rescueNisseFromBuilding(buildingId: string): void {
+    this.mineClaimsMap.delete(buildingId)
+    const state = stateManager.getState()
+    for (const v of Object.values(state.world.villagers)) {
+      if (v.job?.targetId !== buildingId) continue
+      const rt = this.runtime.get(v.id)
+      if (!rt) continue
+      // Make sprite visible in case the Nisse was hidden inside the mine
+      rt.sprite.setVisible(true)
+      rt.nameLabel.setVisible(true)
+      rt.energyBar.setVisible(true)
+      rt.jobIcon.setVisible(true)
+      rt.workTimer = 0
+      rt.idleScanTimer = 0
+      this.claimed.delete(buildingId)
+      this.adapter.send({ type: 'VILLAGER_SET_JOB', villagerId: v.id, job: null })
+      this.adapter.send({ type: 'VILLAGER_SET_AI', villagerId: v.id, aiState: 'idle' })
+      this.addLog(v.id, '! Building demolished — resuming')
+    }
+  }
+
   /**
    * Destroys all Nisse sprites and clears the runtime map.
    * Should be called when the scene shuts down.

src/systems/WorldSystem.ts

@@ -172,6 +172,16 @@ export class WorldSystem {
     this.resourceTiles.delete(tileY * WORLD_TILES + tileX)
   }
 
+  /**
+   * Returns true if a resource (tree or rock) occupies the given tile.
+   * Uses the O(1) resourceTiles index.
+   * @param tileX - Tile column
+   * @param tileY - Tile row
+   */
+  hasResourceAt(tileX: number, tileY: number): boolean {
+    return this.resourceTiles.has(tileY * WORLD_TILES + tileX)
+  }
+
   /**
    * Converts world pixel coordinates to tile coordinates.
    * @param worldX - World X in pixels

src/types.ts

@@ -32,7 +32,7 @@ export const PLANTABLE_TILES = new Set<TileType>([TileType.GRASS, TileType.DARK_
 
 export type ItemId = 'wood' | 'stone' | 'wheat_seed' | 'carrot_seed' | 'wheat' | 'carrot' | 'tree_seed'
 
-export type BuildingType = 'floor' | 'wall' | 'chest' | 'bed' | 'stockpile_zone' | 'forester_hut'
+export type BuildingType = 'floor' | 'wall' | 'chest' | 'bed' | 'stockpile_zone' | 'forester_hut' | 'mine'
 
 export type CropKind = 'wheat' | 'carrot'
 
@@ -81,6 +81,8 @@ export interface BuildingState {
   tileY: number
   kind: BuildingType
   ownerId: string
+  /** In-game time (ms) when the building was placed. Used for demolish refund calculation. */
+  builtAt: number
 }
 
 export interface CropState {
@@ -90,7 +92,11 @@ export interface CropState {
   kind: CropKind
   stage: number
   maxStage: number
-  stageTimerMs: number
+  /** gameTime (ms) when this stage fires at normal (unwatered) speed. */
+  growsAt: number
+  /** gameTime (ms) when this stage fires if the crop is watered (half normal time).
+   *  Both entries are enqueued at plant/stage-advance time; the stale one is skipped. */
+  growsAtWatered: number
   watered: boolean
 }
 
@@ -107,8 +113,8 @@ export interface TreeSeedlingState {
   tileY: number
   /** Growth stage: 0 = sprout, 1 = sapling, 2 = mature (converts to resource). */
   stage: number
-  /** Time remaining until next stage advance, in milliseconds. */
+  /** gameTime (ms) when this seedling advances to the next stage. */
-  stageTimerMs: number
+  growsAt: number
   /** The tile type that was under the seedling when planted (GRASS or DARK_GRASS). */
   underlyingTile: TileType
 }
@@ -125,6 +131,8 @@ export interface ForesterZoneState {
 
 export interface WorldState {
   seed: number
+  /** Accumulated in-game time in milliseconds. Used as the clock for all event-queue timers. */
+  gameTime: number
   tiles: number[]
   resources: Record<string, ResourceNodeState>
   buildings: Record<string, BuildingState>
@@ -134,8 +142,8 @@ export interface WorldState {
   /** Planted tree seedlings, keyed by ID. */
   treeSeedlings: Record<string, TreeSeedlingState>
   /**
-   * Recovery timers for DARK_GRASS tiles, keyed by "tileX,tileY".
+   * Tile recovery fire-times, keyed by "tileX,tileY".
-   * Value is remaining milliseconds until the tile reverts to GRASS.
+   * Value is the gameTime (ms) at which the tile reverts to GRASS.
    */
   tileRecovery: Record<string, number>
   /** Forester zone definitions, keyed by forester_hut building ID. */