diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6311fa0..1400973 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -33,6 +33,12 @@ jobs:
           chmod +x .tools/Godot_v${{ steps.godot-config.outputs.version }}-${{ steps.godot-config.outputs.status }}_linux.x86_64
           ./.tools/Godot_v${{ steps.godot-config.outputs.version }}-${{ steps.godot-config.outputs.status }}_linux.x86_64 --version
 
+      - name: Install Godot system dependencies
+        shell: bash
+        run: |
+          set -euo pipefail
+          sudo apt-get update && sudo apt-get install -y libfontconfig1
+
       - name: Run headless smoke test
         shell: bash
         run: |
diff --git a/scripts/main.gd b/scripts/main.gd
index 7c060b8..8d5f5e8 100644
--- a/scripts/main.gd
+++ b/scripts/main.gd
@@ -16,6 +16,7 @@ const GoalProgression := preload("res://scripts/goal_progression.gd")
 const GoalReward := preload("res://scripts/goal_reward.gd")
 const RESOURCE_TRENDS := Constants.RESOURCE_TRENDS
 const ColonyStance := preload("res://scripts/colony_stance.gd")
+const TileRender := preload("res://scripts/tile_render.gd")
 
 
 @onready var world_grid: GridContainer = %WorldGrid
@@ -2245,39 +2246,29 @@ func worker_texture(name: String, frame: int, carrying: String = "") -> Texture2
 	worker_texture_cache[cache_key] = texture
 	return texture
 
+## Delegates to TileRender.tile_style, passing scene state via context.
 func tile_style(tile: Dictionary, pos: Vector2i) -> StyleBoxFlat:
-	var style := StyleBoxFlat.new()
-	style.corner_radius_top_left = 8
-	style.corner_radius_top_right = 8
-	style.corner_radius_bottom_right = 8
-	style.corner_radius_bottom_left = 8
-	style.border_width_left = 2
-	style.border_width_top = 2
-	style.border_width_right = 2
-	style.border_width_bottom = 2
-	style.content_margin_left = 4
-	style.content_margin_top = 3
-	style.content_margin_right = 4
-	style.content_margin_bottom = 3
-	var kind := "stockpile" if pos == stockpile_pos else String(tile.kind)
-	style.bg_color = TILE_BACKDROPS.get(kind, Color("#1b2128"))
-	style.border_color = tile_accent(tile, pos)
-	style.shadow_color = Color(0, 0, 0, 0.25)
-	style.shadow_size = 2
-	return style
+	var accent := tile_accent(tile, pos)
+	var render_theme := {
+		"TILE_BACKDROPS": TILE_BACKDROPS,
+		"stockpile_pos": stockpile_pos,
+	}
+	return TileRender.tile_style(tile, pos, render_theme, accent)
+
 
+## Delegates to TileRender.tile_accent, passing scene state via context.
 func tile_accent(tile: Dictionary, pos: Vector2i) -> Color:
-	if not pending_build_kind.is_empty() and pos == hovered_tile_pos():
-		return Color("#73d38c") if can_place_at(pos, pending_build_kind) else Color("#d36b6b")
-	if pos == stockpile_pos:
-		return Color("#d4b36f")
-	if RESOURCE_COLORS.has(String(tile.resource)):
-		return RESOURCE_COLORS[String(tile.resource)]
-	if STRUCTURE_COLORS.has(String(tile.kind)):
-		return STRUCTURE_COLORS[String(tile.kind)]
-	if String(tile.kind) == "foundation":
-		return Color("#c7a25e")
-	return Color(1, 1, 1, 0.35)
+	var ctx := {
+		"pending_build_kind": pending_build_kind,
+		"hover_pos": hovered_tile_pos(),
+		"stockpile_pos": stockpile_pos,
+		"can_place_fn": can_place_at,
+	}
+	var render_theme := {
+		"RESOURCE_COLORS": RESOURCE_COLORS,
+		"STRUCTURE_COLORS": STRUCTURE_COLORS,
+	}
+	return TileRender.tile_accent(tile, pos, ctx, render_theme)
 
 func task_name(worker: Dictionary) -> String:
 	if int(worker.get("break_ticks", 0)) > 0:
diff --git a/scripts/tile_render.gd b/scripts/tile_render.gd
new file mode 100644
index 0000000..0d23be1
--- /dev/null
+++ b/scripts/tile_render.gd
@@ -0,0 +1,70 @@
+## Pure tile rendering helpers — no scene references, fully testable.
+## Consumes constants from constants.gd and a context dict from the caller.
+
+class_name TileRender
+
+
+## Returns a StyleBoxFlat for the given tile using the provided theme.
+## `theme` must contain TILE_BACKDROPS (Dictionary of kind → Color).
+static func tile_style(tile: Dictionary, pos: Vector2i, theme: Dictionary, accent_color: Color) -> StyleBoxFlat:
+	var style := StyleBoxFlat.new()
+	style.corner_radius_top_left = 8
+	style.corner_radius_top_right = 8
+	style.corner_radius_bottom_right = 8
+	style.corner_radius_bottom_left = 8
+	style.border_width_left = 2
+	style.border_width_top = 2
+	style.border_width_right = 2
+	style.border_width_bottom = 2
+	style.content_margin_left = 4
+	style.content_margin_top = 3
+	style.content_margin_right = 4
+	style.content_margin_bottom = 3
+
+	var kind := String(tile.kind)
+	if theme.has("stockpile_pos") and pos == theme["stockpile_pos"]:
+		kind = "stockpile"
+
+	style.bg_color = theme.get("TILE_BACKDROPS", {}).get(kind, Color("#1b2128"))
+	style.border_color = accent_color
+	style.shadow_color = Color(0, 0, 0, 0.25)
+	style.shadow_size = 2
+	return style
+
+
+## Returns the accent (border) color for a tile based on context.
+## `context` must contain:
+##   - pending_build_kind: String (empty when not placing)
+##   - hover_pos: Vector2i (-1, -1 when no hover)
+##   - stockpile_pos: Vector2i
+##   - can_place_fn: Callable(pos: Vector2i, kind: String) -> bool
+## `theme` must contain RESOURCE_COLORS and STRUCTURE_COLORS (from constants.gd).
+static func tile_accent(tile: Dictionary, pos: Vector2i, context: Dictionary, theme: Dictionary) -> Color:
+	var pending_build_kind: String = String(context.get("pending_build_kind", ""))
+	var hover_pos: Vector2i = Vector2i(context.get("hover_pos", Vector2i(-1, -1)))
+	var stockpile_pos: Vector2i = Vector2i(context.get("stockpile_pos", Vector2i(-1, -1)))
+	var can_place_fn: Callable = context.get("can_place_fn", func(_p: Vector2i, _k: String): return false)
+
+	# Build placement highlight
+	if not pending_build_kind.is_empty() and pos == hover_pos:
+		return Color("#73d38c") if can_place_fn.call(pos, pending_build_kind) else Color("#d36b6b")
+
+	# Stockpile accent
+	if pos == stockpile_pos:
+		return Color("#d4b36f")
+
+	# Resource accent
+	var resource_colors: Dictionary = theme.get("RESOURCE_COLORS", {})
+	if resource_colors.has(String(tile.resource)):
+		return resource_colors[String(tile.resource)]
+
+	# Structure accent
+	var structure_colors: Dictionary = theme.get("STRUCTURE_COLORS", {})
+	if structure_colors.has(String(tile.kind)):
+		return structure_colors[String(tile.kind)]
+
+	# Foundation accent
+	if String(tile.kind) == "foundation":
+		return Color("#c7a25e")
+
+	return Color(1, 1, 1, 0.35)
diff --git a/smoke.log b/smoke.log
new file mode 100644
index 0000000..9c1ff46
--- /dev/null
+++ b/smoke.log
@@ -0,0 +1,3 @@
+Fontconfig error: Cannot load default config file: No such file: (null)
+Godot Engine v4.2.2.stable.official.15073afe3 - https://godotengine.org
+ 
diff --git a/smoke_ci.log b/smoke_ci.log
new file mode 100644
index 0000000..656d657
--- /dev/null
+++ b/smoke_ci.log
@@ -0,0 +1,3 @@
+libfontconfig.so.1: cannot open shared object file: No such file or directory
+Godot Engine v4.2.2.stable.official.15073afe3 - https://godotengine.org
+ 
diff --git a/tests/test_tile_render.gd b/tests/test_tile_render.gd
new file mode 100644
index 0000000..a5653fd
--- /dev/null
+++ b/tests/test_tile_render.gd
@@ -0,0 +1,316 @@
+## Regression tests for scripts/tile_render.gd.
+## Tests pure rendering functions without scene tree instantiation.
+##
+## Run: godot --headless --quit
+## Or:  godot --headless --main-pack windowstead.pck --script tests/test_tile_render.gd
+
+extends SceneTree
+
+const TileRender := preload("res://scripts/tile_render.gd")
+const C := preload("res://scripts/constants.gd")
+
+
+func _initialize() -> void:
+	var pass_count := 0
+	var fail_count := 0
+	var test_count := 0
+
+	# --- tile_style tests ---
+	test_count += 1; pass_count += test("tile_style returns StyleBoxFlat", _test_tile_style_returns_stylebox)
+	test_count += 1; pass_count += test("tile_style sets border color to accent", _test_tile_style_border_color)
+	test_count += 1; pass_count += test("tile_style uses TILE_BACKDROPS for bg", _test_tile_style_bg_from_backdrops)
+	test_count += 1; pass_count += test("tile_style stockpile override", _test_tile_style_stockpile_override)
+	test_count += 1; pass_count += test("tile_style unknown kind default backdrop", _test_tile_style_unknown_kind)
+	test_count += 1; pass_count += test("tile_style corner radius is 8", _test_tile_style_corner_radius)
+	test_count += 1; pass_count += test("tile_style shadow color and size", _test_tile_style_shadow)
+
+	# --- tile_accent tests ---
+	test_count += 1; pass_count += test("tile_accent build placement valid (green)", _test_accent_build_valid)
+	test_count += 1; pass_count += test("tile_accent build placement invalid (red)", _test_accent_build_invalid)
+	test_count += 1; pass_count += test("tile_accent no build placement default", _test_accent_no_build)
+	test_count += 1; pass_count += test("tile_accent stockpile gold", _test_accent_stockpile)
+	test_count += 1; pass_count += test("tile_accent resource color", _test_accent_resource_color)
+	test_count += 1; pass_count += test("tile_accent structure color", _test_accent_structure_color)
+	test_count += 1; pass_count += test("tile_accent foundation accent", _test_accent_foundation)
+	test_count += 1; pass_count += test("tile_accent hover mismatch no highlight", _test_accent_hover_mismatch)
+	test_count += 1; pass_count += test("tile_accent empty context default", _test_accent_empty_context)
+
+	# --- Integration with constants ---
+	test_count += 1; pass_count += test("tile_accent uses real RESOURCE_COLORS", _test_accent_real_resource_colors)
+	test_count += 1; pass_count += test("tile_accent uses real STRUCTURE_COLORS", _test_accent_real_structure_colors)
+
+	fail_count = test_count - pass_count
+	print("\n=== TileRender Regression Tests ===")
+	print("Passed: %d" % pass_count)
+	print("Failed: %d" % fail_count)
+
+	if fail_count > 0:
+		print("REGRESSION FAILURES DETECTED")
+		quit(1)
+	else:
+		print("All tile_render tests passed.")
+		quit(0)
+
+
+func test(name: String, fn: Callable) -> int:
+	var ok := true
+	var error_msg := ""
+	var result: Variant = fn.call()
+	if result is Dictionary:
+		ok = result.get("ok", false)
+		error_msg = result.get("msg", "no detail")
+	elif result == false:
+		ok = false
+		error_msg = "returned false"
+
+	if ok:
+		print("  ✓ %s" % name)
+		return 1
+	else:
+		print("  ✗ %s: %s" % [name, error_msg])
+		return 0
+
+
+# --- tile_style tests ---
+
+func _test_tile_style_returns_stylebox() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var theme := {"TILE_BACKDROPS": {"ground": Color("#1b2128")}}
+	var accent := Color(1, 1, 1, 0.35)
+	var style := TileRender.tile_style(tile, pos, theme, accent)
+	return style is StyleBoxFlat
+
+
+func _test_tile_style_border_color() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var theme := {"TILE_BACKDROPS": {}}
+	var accent := Color(0.5, 0.3, 0.1, 1.0)
+	var style := TileRender.tile_style(tile, pos, theme, accent)
+	return style.border_color == accent
+
+
+func _test_tile_style_bg_from_backdrops() -> bool:
+	var tile := {"kind": "tree", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var theme := {"TILE_BACKDROPS": {"tree": Color("#2d4a2d")}}
+	var accent := Color(1, 1, 1, 0.35)
+	var style := TileRender.tile_style(tile, pos, theme, accent)
+	return style.bg_color == Color("#2d4a2d")
+
+
+func _test_tile_style_stockpile_override() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(5, 3)
+	var theme := {
+		"TILE_BACKDROPS": {"ground": Color("#1b2128"), "stockpile": Color("#d4b36f")},
+		"stockpile_pos": Vector2i(5, 3),
+	}
+	var accent := Color(1, 1, 1, 0.35)
+	var style := TileRender.tile_style(tile, pos, theme, accent)
+	return style.bg_color == Color("#d4b36f")
+
+
+func _test_tile_style_unknown_kind() -> bool:
+	var tile := {"kind": "unknown", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var theme := {"TILE_BACKDROPS": {}}
+	var accent := Color(1, 1, 1, 0.35)
+	var style := TileRender.tile_style(tile, pos, theme, accent)
+	return style.bg_color == Color("#1b2128")
+
+
+func _test_tile_style_corner_radius() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var theme := {"TILE_BACKDROPS": {}}
+	var accent := Color(1, 1, 1, 0.35)
+	var style := TileRender.tile_style(tile, pos, theme, accent)
+	return (style.corner_radius_top_left == 8 and
+			style.corner_radius_top_right == 8 and
+			style.corner_radius_bottom_right == 8 and
+			style.corner_radius_bottom_left == 8)
+
+
+func _test_tile_style_shadow() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var theme := {"TILE_BACKDROPS": {}}
+	var accent := Color(1, 1, 1, 0.35)
+	var style := TileRender.tile_style(tile, pos, theme, accent)
+	return style.shadow_color == Color(0, 0, 0, 0.25) and style.shadow_size == 2
+
+
+# --- tile_accent tests ---
+
+func _test_accent_build_valid() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(2, 2)
+	var can_place_fn := func(_p: Vector2i, _k: String): return true
+	var context := {
+		"pending_build_kind": "house",
+		"hover_pos": Vector2i(2, 2),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": can_place_fn,
+	}
+	var theme := {"RESOURCE_COLORS": {}, "STRUCTURE_COLORS": {}}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color("#73d38c")
+
+
+func _test_accent_build_invalid() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(2, 2)
+	var can_place_fn := func(_p: Vector2i, _k: String): return false
+	var context := {
+		"pending_build_kind": "house",
+		"hover_pos": Vector2i(2, 2),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": can_place_fn,
+	}
+	var theme := {"RESOURCE_COLORS": {}, "STRUCTURE_COLORS": {}}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color("#d36b6b")
+
+
+func _test_accent_no_build() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(2, 2)
+	var context := {
+		"pending_build_kind": "",
+		"hover_pos": Vector2i(2, 2),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": func(_p: Vector2i, _k: String): return true,
+	}
+	var theme := {"RESOURCE_COLORS": {}, "STRUCTURE_COLORS": {}}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color(1, 1, 1, 0.35)
+
+
+func _test_accent_stockpile() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(5, 3)
+	var context := {
+		"pending_build_kind": "",
+		"hover_pos": Vector2i(-1, -1),
+		"stockpile_pos": Vector2i(5, 3),
+		"can_place_fn": func(_p: Vector2i, _k: String): return true,
+	}
+	var theme := {"RESOURCE_COLORS": {}, "STRUCTURE_COLORS": {}}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color("#d4b36f")
+
+
+func _test_accent_resource_color() -> bool:
+	var tile := {"kind": "ground", "resource": "wood"}
+	var pos := Vector2i(0, 0)
+	var context := {
+		"pending_build_kind": "",
+		"hover_pos": Vector2i(-1, -1),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": func(_p: Vector2i, _k: String): return true,
+	}
+	var theme := {
+		"RESOURCE_COLORS": {"wood": Color("#8b5e3c")},
+		"STRUCTURE_COLORS": {},
+	}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color("#8b5e3c")
+
+
+func _test_accent_structure_color() -> bool:
+	var tile := {"kind": "house", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var context := {
+		"pending_build_kind": "",
+		"hover_pos": Vector2i(-1, -1),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": func(_p: Vector2i, _k: String): return true,
+	}
+	var theme := {
+		"RESOURCE_COLORS": {},
+		"STRUCTURE_COLORS": {"house": Color("#6b8cce")},
+	}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color("#6b8cce")
+
+
+func _test_accent_foundation() -> bool:
+	var tile := {"kind": "foundation", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var context := {
+		"pending_build_kind": "",
+		"hover_pos": Vector2i(-1, -1),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": func(_p: Vector2i, _k: String): return true,
+	}
+	var theme := {"RESOURCE_COLORS": {}, "STRUCTURE_COLORS": {}}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color("#c7a25e")
+
+
+func _test_accent_hover_mismatch() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(3, 3)
+	var context := {
+		"pending_build_kind": "house",
+		"hover_pos": Vector2i(2, 2),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": func(_p: Vector2i, _k: String): return true,
+	}
+	var theme := {"RESOURCE_COLORS": {}, "STRUCTURE_COLORS": {}}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color(1, 1, 1, 0.35)
+
+
+func _test_accent_empty_context() -> bool:
+	var tile := {"kind": "ground", "resource": ""}
+	var pos := Vector2i(0, 0)
+	var context := {}
+	var theme := {}
+	return TileRender.tile_accent(tile, pos, context, theme) == Color(1, 1, 1, 0.35)
+
+
+# --- Integration with real constants ---
+
+func _test_accent_real_resource_colors() -> bool:
+	# Verify tile_accent uses RESOURCE_COLORS from constants.gd
+	var wood_tile := {"kind": "ground", "resource": "wood"}
+	var stone_tile := {"kind": "ground", "resource": "stone"}
+	var food_tile := {"kind": "ground", "resource": "food"}
+	var context := {
+		"pending_build_kind": "",
+		"hover_pos": Vector2i(-1, -1),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": func(_p: Vector2i, _k: String): return true,
+	}
+	var theme := {
+		"RESOURCE_COLORS": C.RESOURCE_COLORS,
+		"STRUCTURE_COLORS": {},
+	}
+
+	var wood_color := TileRender.tile_accent(wood_tile, Vector2i(0, 0), context, theme)
+	var stone_color := TileRender.tile_accent(stone_tile, Vector2i(0, 0), context, theme)
+	var food_color := TileRender.tile_accent(food_tile, Vector2i(0, 0), context, theme)
+
+	return (wood_color == C.RESOURCE_COLORS["wood"] and
+			stone_color == C.RESOURCE_COLORS["stone"] and
+			food_color == C.RESOURCE_COLORS["food"])
+
+
+func _test_accent_real_structure_colors() -> bool:
+	# Verify tile_accent uses STRUCTURE_COLORS from constants.gd
+	var hut_tile := {"kind": "hut", "resource": ""}
+	var workshop_tile := {"kind": "workshop", "resource": ""}
+	var garden_tile := {"kind": "garden", "resource": ""}
+	var context := {
+		"pending_build_kind": "",
+		"hover_pos": Vector2i(-1, -1),
+		"stockpile_pos": Vector2i(-1, -1),
+		"can_place_fn": func(_p: Vector2i, _k: String): return true,
+	}
+	var theme := {
+		"RESOURCE_COLORS": {},
+		"STRUCTURE_COLORS": C.STRUCTURE_COLORS,
+	}
+
+	var hut_color := TileRender.tile_accent(hut_tile, Vector2i(0, 0), context, theme)
+	var workshop_color := TileRender.tile_accent(workshop_tile, Vector2i(0, 0), context, theme)
+	var garden_color := TileRender.tile_accent(garden_tile, Vector2i(0, 0), context, theme)
+
+	return (hut_color == C.STRUCTURE_COLORS["hut"] and
+			workshop_color == C.STRUCTURE_COLORS["workshop"] and
+			garden_color == C.STRUCTURE_COLORS["garden"])