Unify action-button states across the UI

- Add UiStyles with explicit normal, hover, pressed, focus and disabled styles and apply it to every action button.
- Disable timeline Previous/Next at the first/last event and keep Close always available.
- Style settings reset-dialog buttons and cover the button-state audit in docs/ui-copy.md.
- Add shared-state and timeline-boundary regression tests.

src/game/ui/event_timeline.gd

@@ -9,12 +9,15 @@ signal closed()
 
 const Strings := preload("res://src/core/strings.gd")
 const UiArt := preload("res://src/game/ui/art.gd")
+const UiStyles := preload("res://src/game/ui/ui_styles.gd")
 
 var events: Array[Dictionary] = []
 var index := 0
 var _list_label: Label = null
 var _detail_label: Label = null
 var _counter_label: Label = null
+var _prev_button: Button = null
+var _next_button: Button = null
 var _root: Control = null
 
 func _init() -> void:
@@ -90,22 +93,25 @@ func _build() -> void:
 	row.add_theme_constant_override("separation", 10)
 	column.add_child(row)
 
-	var prev := Button.new()
-	prev.name = "PrevButton"
-	prev.text = Strings.lookup("timeline.prev")
-	prev.pressed.connect(func(): step(-1))
-	row.add_child(prev)
+	_prev_button = Button.new()
+	_prev_button.name = "PrevButton"
+	_prev_button.text = Strings.lookup("timeline.prev")
+	_prev_button.pressed.connect(func(): step(-1))
+	UiStyles.apply_button(_prev_button, 15, true)
+	row.add_child(_prev_button)
 
-	var next := Button.new()
-	next.name = "NextButton"
-	next.text = Strings.lookup("timeline.next")
-	next.pressed.connect(func(): step(1))
-	row.add_child(next)
+	_next_button = Button.new()
+	_next_button.name = "NextButton"
+	_next_button.text = Strings.lookup("timeline.next")
+	_next_button.pressed.connect(func(): step(1))
+	UiStyles.apply_button(_next_button, 15, true)
+	row.add_child(_next_button)
 
 	var close := Button.new()
 	close.name = "CloseButton"
 	close.text = Strings.lookup("timeline.close")
 	close.pressed.connect(_on_close)
+	UiStyles.apply_button(close, 15, true)
 	row.add_child(close)
 
 	var hint := Label.new()
@@ -154,7 +160,12 @@ func _on_close() -> void:
 	close()
 
 func _refresh() -> void:
-	if events.is_empty():
+	var has_events := not events.is_empty()
+	if _prev_button:
+		_prev_button.disabled = not has_events or index <= 0
+	if _next_button:
+		_next_button.disabled = not has_events or index >= events.size() - 1
+	if not has_events:
 		_counter_label.text = Strings.lookup("timeline.empty")
 		_detail_label.text = ""
 		_list_label.text = ""

src/game/ui/help_overlay.gd

@@ -4,6 +4,7 @@ extends CanvasLayer
 
 const Strings := preload("res://src/core/strings.gd")
 const InputBindings := preload("res://src/core/input_bindings.gd")
+const UiStyles := preload("res://src/game/ui/ui_styles.gd")
 
 signal closed()
 
@@ -70,6 +71,7 @@ func _build() -> void:
 	close.text = Strings.lookup("ui.help_close")
 	close.pressed.connect(func(): close_panel())
 	close.size_flags_horizontal = Control.SIZE_SHRINK_CENTER
+	UiStyles.apply_button(close, 16)
 	column.add_child(close)
 
 func open(policy: String = "") -> void:

src/game/ui/pause_overlay.gd

@@ -10,6 +10,7 @@ signal settings_requested()
 signal quit_to_menu_requested()
 
 const UiArt := preload("res://src/game/ui/art.gd")
+const UiStyles := preload("res://src/game/ui/ui_styles.gd")
 const Strings := preload("res://src/core/strings.gd")
 
 var _root: Control = null
@@ -67,19 +68,7 @@ func _add_button(parent: Control, text: String, node_name: String, cb: Callable)
 	button.name = node_name
 	button.text = text
 	button.custom_minimum_size = Vector2(380, 52)
-	button.add_theme_font_size_override("font_size", 22)
-	var normal := StyleBoxFlat.new()
-	normal.bg_color = Color(0.115, 0.125, 0.15, 0.96)
-	normal.corner_radius_top_left = 12
-	normal.corner_radius_top_right = 12
-	normal.corner_radius_bottom_left = 12
-	normal.corner_radius_bottom_right = 12
-	var hover := normal.duplicate() as StyleBoxFlat
-	hover.bg_color = Color(0.16, 0.175, 0.21, 0.98)
-	button.add_theme_stylebox_override("normal", normal)
-	button.add_theme_stylebox_override("hover", hover)
-	button.add_theme_stylebox_override("focus", hover)
-	button.add_theme_stylebox_override("pressed", hover)
+	UiStyles.apply_button(button, 22)
 	button.pressed.connect(cb)
 	parent.add_child(button)
 	return button

src/game/ui/radio_panel.gd

@@ -10,6 +10,7 @@ signal cancelled()
 const Rules := preload("res://src/core/rules.gd")
 const Strings := preload("res://src/core/strings.gd")
 const UiArt := preload("res://src/game/ui/art.gd")
+const UiStyles := preload("res://src/game/ui/ui_styles.gd")
 
 var panel: PanelContainer
 var npc_name_label: Label
@@ -107,10 +108,12 @@ func _init() -> void:
 	action_button.button_down.connect(func(): _start_hold())
 	action_button.button_up.connect(func(): _stop_hold(false))
 	action_button.pressed.connect(_on_action_pressed)
+	UiStyles.apply_button(action_button, 16)
 	buttons.add_child(action_button)
 	var cancel_btn := Button.new()
 	cancel_btn.text = Strings.lookup("ui.radio_cancel")
 	cancel_btn.pressed.connect(func(): cancelled.emit())
+	UiStyles.apply_button(cancel_btn, 16)
 	buttons.add_child(cancel_btn)
 
 var _title_label: Label

src/game/ui/settings_panel.gd

@@ -8,6 +8,7 @@ extends CanvasLayer
 
 const InputBindings := preload("res://src/core/input_bindings.gd")
 const UiArt := preload("res://src/game/ui/art.gd")
+const UiStyles := preload("res://src/game/ui/ui_styles.gd")
 const Strings := preload("res://src/core/strings.gd")
 
 signal applied(settings: Dictionary)
@@ -135,11 +136,13 @@ func _build() -> void:
 	replay.name = "ReplayTutorialButton"
 	replay.text = Strings.lookup("ui.settings_replay")
 	replay.pressed.connect(func(): replay_tutorial_requested.emit())
+	UiStyles.apply_button(replay, 16)
 	replay_row.add_child(replay)
 	var reset_campaign := Button.new()
 	reset_campaign.name = "ResetCampaignButton"
 	reset_campaign.text = Strings.lookup("ui.settings_reset_campaign")
 	reset_campaign.pressed.connect(_confirm_reset_campaign)
+	UiStyles.apply_button(reset_campaign, 16)
 	replay_row.add_child(reset_campaign)
 
 	var controls_title := Label.new()
@@ -160,6 +163,7 @@ func _build() -> void:
 		var button := Button.new()
 		button.custom_minimum_size = Vector2(130, 0)
 		button.pressed.connect(_on_rebind.bind(action))
+		UiStyles.apply_button(button, 14, true)
 		grid.add_child(button)
 		_bind_buttons[action] = button
 
@@ -172,12 +176,14 @@ func _build() -> void:
 	save_button.name = "ApplyButton"
 	save_button.text = Strings.lookup("ui.apply_settings")
 	save_button.pressed.connect(_on_apply)
+	UiStyles.apply_button(save_button, 16)
 	row.add_child(save_button)
 
 	var cancel_button := Button.new()
 	cancel_button.name = "CancelButton"
 	cancel_button.text = Strings.lookup("ui.settings_cancel")
 	cancel_button.pressed.connect(_on_cancel)
+	UiStyles.apply_button(cancel_button, 16)
 	row.add_child(cancel_button)
 
 func _add_label_row(parent: Control, text: String) -> Label:
@@ -273,6 +279,8 @@ func _confirm_reset_campaign() -> void:
 	dialog.dialog_text = Strings.lookup("ui.settings_reset_confirm")
 	dialog.confirmed.connect(func(): reset_campaign_requested.emit())
 	add_child(dialog)
+	UiStyles.apply_button(dialog.get_ok_button(), 16)
+	UiStyles.apply_button(dialog.get_cancel_button(), 16)
 	dialog.popup_centered()
 	dialog.confirmed.connect(dialog.queue_free)
 

src/game/ui/shift_review.gd

@@ -4,6 +4,7 @@ extends CanvasLayer
 
 const Strings := preload("res://src/core/strings.gd")
 const UiArt := preload("res://src/game/ui/art.gd")
+const UiStyles := preload("res://src/game/ui/ui_styles.gd")
 
 signal restart_requested()
 signal continue_requested()
@@ -85,19 +86,7 @@ func _init() -> void:
 
 func _style_review_button(button: Button) -> void:
 	button.custom_minimum_size = Vector2(300, 52)
-	button.add_theme_font_size_override("font_size", 22)
-	var normal := StyleBoxFlat.new()
-	normal.bg_color = Color(0.115, 0.125, 0.15, 0.96)
-	normal.corner_radius_top_left = 10
-	normal.corner_radius_top_right = 10
-	normal.corner_radius_bottom_left = 10
-	normal.corner_radius_bottom_right = 10
-	var hover := normal.duplicate() as StyleBoxFlat
-	hover.bg_color = Color(0.16, 0.175, 0.21, 0.98)
-	button.add_theme_stylebox_override("normal", normal)
-	button.add_theme_stylebox_override("hover", hover)
-	button.add_theme_stylebox_override("focus", hover)
-	button.add_theme_stylebox_override("pressed", hover)
+	UiStyles.apply_button(button, 22)
 
 func show_review(review: Dictionary, scenario: Resource, history: Array = [],
 		campaign_summary: Dictionary = {}) -> void:

src/game/ui/start_menu.gd

@@ -11,6 +11,7 @@ signal settings_requested()
 signal quit_requested()
 
 const UiArt := preload("res://src/game/ui/art.gd")
+const UiStyles := preload("res://src/game/ui/ui_styles.gd")
 const Strings := preload("res://src/core/strings.gd")
 
 const VENUES := [
@@ -108,7 +109,7 @@ func _build() -> void:
 	_continue_button.name = "ContinueButton"
 	_continue_button.custom_minimum_size = Vector2(460, 52)
 	_continue_button.pressed.connect(_on_continue_pressed)
-	_style_venue_button(_continue_button)
+	UiStyles.apply_button(_continue_button, 18)
 	column.add_child(_continue_button)
 
 	for i in VENUES.size():
@@ -119,7 +120,7 @@ func _build() -> void:
 		button.alignment = HORIZONTAL_ALIGNMENT_LEFT
 		button.custom_minimum_size = Vector2(460, 62)
 		button.pressed.connect(_on_venue_pressed.bind(i))
-		_style_venue_button(button)
+		UiStyles.apply_button(button, 18)
 		column.add_child(button)
 		_buttons.append(button)
 
@@ -136,18 +137,21 @@ func _build() -> void:
 	help_button.name = "HelpButton"
 	help_button.text = Strings.lookup("ui.start_help")
 	help_button.pressed.connect(func(): help_requested.emit())
+	UiStyles.apply_button(help_button, 16)
 	row.add_child(help_button)
 
 	var settings_button := Button.new()
 	settings_button.name = "SettingsButton"
 	settings_button.text = Strings.lookup("ui.start_settings")
 	settings_button.pressed.connect(func(): settings_requested.emit())
+	UiStyles.apply_button(settings_button, 16)
 	row.add_child(settings_button)
 
 	var quit_button := Button.new()
 	quit_button.name = "QuitButton"
 	quit_button.text = Strings.lookup("ui.quit_game")
 	quit_button.pressed.connect(func(): quit_requested.emit())
+	UiStyles.apply_button(quit_button, 16)
 	row.add_child(quit_button)
 
 	var hint := Label.new()
@@ -158,35 +162,6 @@ func _build() -> void:
 
 	_focus_index(0)
 
-## Match the dark, rounded rows in the `start_menu` mockup.
-func _style_venue_button(button: Button) -> void:
-	button.add_theme_font_size_override("font_size", 18)
-	button.add_theme_color_override("font_color", Color(0.94, 0.94, 0.92))
-	button.add_theme_color_override("font_hover_color", Color.WHITE)
-	var normal := StyleBoxFlat.new()
-	normal.bg_color = Color(0.115, 0.125, 0.15, 0.96)
-	normal.corner_radius_top_left = 12
-	normal.corner_radius_top_right = 12
-	normal.corner_radius_bottom_left = 12
-	normal.corner_radius_bottom_right = 12
-	normal.content_margin_left = 22
-	normal.content_margin_right = 22
-	normal.content_margin_top = 10
-	normal.content_margin_bottom = 10
-	var hover := normal.duplicate() as StyleBoxFlat
-	hover.bg_color = Color(0.16, 0.175, 0.21, 0.98)
-	var focus := normal.duplicate() as StyleBoxFlat
-	focus.bg_color = Color(0.14, 0.155, 0.19, 0.98)
-	focus.border_color = Color(0.85, 0.86, 0.88)
-	focus.border_width_left = 2
-	focus.border_width_top = 2
-	focus.border_width_right = 2
-	focus.border_width_bottom = 2
-	button.add_theme_stylebox_override("normal", normal)
-	button.add_theme_stylebox_override("hover", hover)
-	button.add_theme_stylebox_override("focus", focus)
-	button.add_theme_stylebox_override("pressed", hover)
-
 func _focus_index(i: int) -> void:
 	if _buttons.is_empty():
 		return

src/game/ui/ui_styles.gd

@@ -0,0 +1,58 @@
+class_name UiStyles
+extends RefCounted
+## Shared button states for the dark session/UI shell.
+##
+## Keeping one style table means every normal/hover/pressed/focused/disabled
+## state is explicit. Buttons that use the Godot default theme otherwise look
+## different from the custom start-menu, pause and review rows as soon as they
+## are disabled or receive keyboard focus.
+
+const TEXT := Color(0.94, 0.94, 0.92)
+const TEXT_HOVER := Color.WHITE
+const TEXT_DISABLED := Color(0.48, 0.50, 0.56)
+const SURFACE := Color(0.115, 0.125, 0.15, 0.96)
+const SURFACE_HOVER := Color(0.16, 0.175, 0.21, 0.98)
+const SURFACE_PRESSED := Color(0.075, 0.085, 0.105, 0.98)
+const SURFACE_DISABLED := Color(0.075, 0.08, 0.095, 0.72)
+const ACCENT := Color(0.78, 0.82, 0.88, 0.9)
+
+static func apply_button(button: Button, font_size: int = 0, compact: bool = false) -> void:
+	if button == null:
+		return
+	if font_size > 0:
+		button.add_theme_font_size_override("font_size", font_size)
+	var margin_h := 12 if compact else 18
+	var margin_v := 7 if compact else 10
+	var normal := _box(SURFACE, margin_h, margin_v)
+	var hover := _box(SURFACE_HOVER, margin_h, margin_v)
+	var pressed := _box(SURFACE_PRESSED, margin_h, margin_v)
+	var disabled := _box(SURFACE_DISABLED, margin_h, margin_v)
+	var focus := _box(Color(0, 0, 0, 0), margin_h, margin_v)
+	focus.border_color = ACCENT
+	focus.border_width_left = 2
+	focus.border_width_top = 2
+	focus.border_width_right = 2
+	focus.border_width_bottom = 2
+	button.add_theme_stylebox_override("normal", normal)
+	button.add_theme_stylebox_override("hover", hover)
+	button.add_theme_stylebox_override("pressed", pressed)
+	button.add_theme_stylebox_override("focus", focus)
+	button.add_theme_stylebox_override("disabled", disabled)
+	button.add_theme_color_override("font_color", TEXT)
+	button.add_theme_color_override("font_hover_color", TEXT_HOVER)
+	button.add_theme_color_override("font_pressed_color", TEXT_HOVER)
+	button.add_theme_color_override("font_focus_color", TEXT_HOVER)
+	button.add_theme_color_override("font_disabled_color", TEXT_DISABLED)
+
+static func _box(color: Color, margin_h: int, margin_v: int) -> StyleBoxFlat:
+	var box := StyleBoxFlat.new()
+	box.bg_color = color
+	box.corner_radius_top_left = 10
+	box.corner_radius_top_right = 10
+	box.corner_radius_bottom_left = 10
+	box.corner_radius_bottom_right = 10
+	box.content_margin_left = margin_h
+	box.content_margin_right = margin_h
+	box.content_margin_top = margin_v
+	box.content_margin_bottom = margin_v
+	return box

src/test/tests/test_event_timeline.gd

@@ -79,14 +79,21 @@ func test_empty_timeline_is_safe() -> bool:
 func test_stepping_clamps() -> bool:
 	var timeline: Node = EventTimeline.new()
 	timeline.show_timeline(_review())
+	var prev: Button = timeline.find_child("PrevButton", true, false) as Button
+	var next: Button = timeline.find_child("NextButton", true, false) as Button
+	var start_prev_disabled := prev != null and prev.disabled
+	var start_next_enabled := next != null and not next.disabled
 	timeline.step(-1)
 	var a := TestUtils.check_eq(timeline.index, 0, "cannot step before the first event")
 	timeline.step(1)
 	var b := TestUtils.check_eq(timeline.index, 1, "next advances one event")
 	timeline.step(99)
 	var c := TestUtils.check_eq(timeline.index, 3, "cannot step past the last event")
+	var end_next_disabled := next != null and next.disabled
+	var d := TestUtils.check(start_prev_disabled and start_next_enabled and end_next_disabled,
+		"timeline boundary buttons disable at the ends")
 	timeline.free()
-	return a and b and c
+	return a and b and c and d
 
 func test_review_records_a_shift_start_stamp() -> bool:
 	var coordinator: Object = Coordinator.new()

src/test/tests/test_ui_buttons.gd

@@ -0,0 +1,26 @@
+extends RefCounted
+## Shared UI button states: every normal/hover/pressed/focus/disabled state is
+## explicitly styled so the custom dark panels do not fall back to the engine
+## theme when a control is focused or disabled.
+
+const UiStyles := preload("res://src/game/ui/ui_styles.gd")
+
+func test_shared_button_states_are_complete() -> bool:
+	var button := Button.new()
+	UiStyles.apply_button(button, 16)
+	var states := ["normal", "hover", "pressed", "focus", "disabled"]
+	var missing: Array[String] = []
+	for state in states:
+		if not button.has_theme_stylebox_override(state):
+			missing.append(state)
+	var a := TestUtils.check(missing.is_empty(),
+		"all five button states have explicit styles (missing: %s)" % str(missing))
+	var b := TestUtils.check_eq(button.get_theme_font_size("font_size"), 16,
+		"the shared style applies the requested font size")
+	var disabled := button.get_theme_stylebox("disabled")
+	var normal := button.get_theme_stylebox("normal")
+	var c := TestUtils.check(disabled != null and normal != null
+		and disabled.bg_color != normal.bg_color,
+		"the disabled state is visually distinct from normal")
+	button.free()
+	return a and b and c