feat(tui): detect terminal theme and apply palettes

11 files changed, 260 insertions, 46 deletions

diff --git a/internal/tui/common/styles.go b/internal/tui/common/styles.go
index 06ed596..a71ef81 100644
--- a/internal/tui/common/styles.go
+++ b/internal/tui/common/styles.go
@@ -1,59 +1,117 @@
 package common
 
-import "charm.land/lipgloss/v2"
+import (
+	"image/color"
+
+	"charm.land/lipgloss/v2"
+)
+
+// Palette defines themed colors shared across the TUI package.
+type Palette struct {
+	Background color.Color
+	Panel      color.Color
+	Primary    color.Color
+	Accent     color.Color
+	Muted      color.Color
+	Text       color.Color
+	Danger     color.Color
+}
+
+// NewPalette returns a color palette for dark or light terminal backgrounds.
+func NewPalette(isDark bool) Palette {
+	if isDark {
+		return Palette{
+			Background: lipgloss.Color("235"),
+			Panel:      lipgloss.Color("238"),
+			Primary:    lipgloss.Color("75"),
+			Accent:     lipgloss.Color("222"),
+			Muted:      lipgloss.Color("246"),
+			Text:       lipgloss.Color("255"),
+			Danger:     lipgloss.Color("203"),
+		}
+	}
+
+	return Palette{
+		Background: lipgloss.Color("255"),
+		Panel:      lipgloss.Color("250"),
+		Primary:    lipgloss.Color("26"),
+		Accent:     lipgloss.Color("88"),
+		Muted:      lipgloss.Color("242"),
+		Text:       lipgloss.Color("235"),
+		Danger:     lipgloss.Color("160"),
+	}
+}
 
 var (
 	// Palette colors shared across the TUI package.
-	ColorBackground = lipgloss.Color("235")
-	ColorPanel      = lipgloss.Color("238")
-	ColorPrimary    = lipgloss.Color("75")
-	ColorAccent     = lipgloss.Color("222")
-	ColorMuted      = lipgloss.Color("246")
-	ColorText       = lipgloss.Color("255")
-	ColorDanger     = lipgloss.Color("203")
+	ColorBackground color.Color
+	ColorPanel      color.Color
+	ColorPrimary    color.Color
+	ColorAccent     color.Color
+	ColorMuted      color.Color
+	ColorText       color.Color
+	ColorDanger     color.Color
 )
 
 var (
 	// ScreenStyle is the base style for full-screen models.
-	ScreenStyle = lipgloss.NewStyle().
-			Foreground(ColorText)
+	ScreenStyle lipgloss.Style
 
 	// HeaderStyle is used by top-level titles and screen headers.
-	HeaderStyle = lipgloss.NewStyle().
-			Bold(true).
-			Foreground(ColorPrimary)
+	HeaderStyle lipgloss.Style
 
 	// TabActiveStyle is applied to the currently-selected tab.
-	TabActiveStyle = lipgloss.NewStyle().
-			Bold(true).
-			Foreground(ColorBackground).
-			Background(ColorPrimary).
-			Padding(0, 1)
+	TabActiveStyle lipgloss.Style
 
 	// TabInactiveStyle is applied to non-selected tabs.
-	TabInactiveStyle = lipgloss.NewStyle().
-				Foreground(ColorMuted).
-				Padding(0, 1)
+	TabInactiveStyle lipgloss.Style
 
 	// PanelStyle is used for boxed sections.
-	PanelStyle = lipgloss.NewStyle().
-			Border(lipgloss.NormalBorder()).
-			BorderForeground(ColorPanel).
-			Padding(0, 1)
+	PanelStyle lipgloss.Style
 
 	// HelpBarStyle is used for keybinding hints at the bottom.
-	HelpBarStyle = lipgloss.NewStyle().
-			Foreground(ColorMuted).
-			BorderTop(true).
-			BorderForeground(ColorPanel)
+	HelpBarStyle lipgloss.Style
 
 	// HighlightStyle emphasizes inline values.
-	HighlightStyle = lipgloss.NewStyle().
-			Bold(true).
-			Foreground(ColorAccent)
+	HighlightStyle lipgloss.Style
 
 	// ErrorStyle is used for fatal or warning messages.
-	ErrorStyle = lipgloss.NewStyle().
-			Bold(true).
-			Foreground(ColorDanger)
+	ErrorStyle lipgloss.Style
 )
+
+// ApplyPalette updates shared colors and styles to match the provided theme.
+func ApplyPalette(isDark bool) {
+	palette := NewPalette(isDark)
+	ColorBackground = palette.Background
+	ColorPanel = palette.Panel
+	ColorPrimary = palette.Primary
+	ColorAccent = palette.Accent
+	ColorMuted = palette.Muted
+	ColorText = palette.Text
+	ColorDanger = palette.Danger
+
+	ScreenStyle = lipgloss.NewStyle().Foreground(ColorText)
+	HeaderStyle = lipgloss.NewStyle().Bold(true).Foreground(ColorPrimary)
+	TabActiveStyle = lipgloss.NewStyle().
+		Bold(true).
+		Foreground(ColorBackground).
+		Background(ColorPrimary).
+		Padding(0, 1)
+	TabInactiveStyle = lipgloss.NewStyle().
+		Foreground(ColorMuted).
+		Padding(0, 1)
+	PanelStyle = lipgloss.NewStyle().
+		Border(lipgloss.NormalBorder()).
+		BorderForeground(ColorPanel).
+		Padding(0, 1)
+	HelpBarStyle = lipgloss.NewStyle().
+		Foreground(ColorMuted).
+		BorderTop(true).
+		BorderForeground(ColorPanel)
+	HighlightStyle = lipgloss.NewStyle().Bold(true).Foreground(ColorAccent)
+	ErrorStyle = lipgloss.NewStyle().Bold(true).Foreground(ColorDanger)
+}
+
+func init() {
+	ApplyPalette(true)
+}
diff --git a/internal/tui/common/styles_test.go b/internal/tui/common/styles_test.go
new file mode 100644
index 0000000..c0900b3
--- /dev/null
+++ b/internal/tui/common/styles_test.go
@@ -0,0 +1,39 @@
+package common
+
+import (
+	"testing"
+
+	"charm.land/lipgloss/v2"
+)
+
+func TestNewPaletteRendersDistinctThemes(t *testing.T) {
+	dark := NewPalette(true)
+	light := NewPalette(false)
+
+	darkRender := lipgloss.NewStyle().
+		Foreground(dark.Text).
+		Background(dark.Background).
+		Render("ior")
+	lightRender := lipgloss.NewStyle().
+		Foreground(light.Text).
+		Background(light.Background).
+		Render("ior")
+
+	if darkRender == lightRender {
+		t.Fatalf("expected dark and light palettes to render differently")
+	}
+}
+
+func TestApplyPaletteUpdatesSharedStyles(t *testing.T) {
+	t.Cleanup(func() { ApplyPalette(true) })
+
+	ApplyPalette(true)
+	dark := ScreenStyle.Render("ior")
+
+	ApplyPalette(false)
+	light := ScreenStyle.Render("ior")
+
+	if dark == light {
+		t.Fatalf("expected ScreenStyle render to differ between dark and light palettes")
+	}
+}
diff --git a/internal/tui/dashboard/model.go b/internal/tui/dashboard/model.go
index ac61982..a4cd4a5 100644
--- a/internal/tui/dashboard/model.go
+++ b/internal/tui/dashboard/model.go
@@ -47,6 +47,7 @@ type Model struct {
 	processesOffset int
 	streamModel     eventstream.Model
 	showHelp        bool
+	isDark          bool
 }
 
 // NewModel creates a dashboard model with default refresh cadence.
@@ -59,14 +60,17 @@ func NewModelWithConfig(engine SnapshotSource, streamSource *eventstream.RingBuf
 	if refreshMs <= 0 {
 		refreshMs = defaultRefreshMs
 	}
-	return Model{
+	m := Model{
 		activeTab:    TabOverview,
 		engine:       engine,
 		refreshEvery: time.Duration(refreshMs) * time.Millisecond,
 		keys:         keys,
 		pidFilter:    -1,
 		streamModel:  eventstream.NewModel(streamSource),
+		isDark:       true,
 	}
+	m.SetDarkMode(true)
+	return m
 }
 
 // Init starts periodic refresh ticks.
@@ -282,6 +286,12 @@ func (m *Model) SetStreamSource(source *eventstream.RingBuffer) {
 	m.streamModel.SetSource(source)
 }
 
+// SetDarkMode updates dashboard child models for the active theme.
+func (m *Model) SetDarkMode(isDark bool) {
+	m.isDark = isDark
+	m.streamModel.SetDarkMode(isDark)
+}
+
 // SetPidFilter updates the active PID filter used by tab render hints.
 func (m *Model) SetPidFilter(pid int) {
 	m.pidFilter = pid
diff --git a/internal/tui/eventstream/exportmodal.go b/internal/tui/eventstream/exportmodal.go
index ec35343..3c0e2cd 100644
--- a/internal/tui/eventstream/exportmodal.go
+++ b/internal/tui/eventstream/exportmodal.go
@@ -19,6 +19,7 @@ func NewExportModal() ExportModal {
 	input.Prompt = ""
 	input.CharLimit = 0
 	input.SetWidth(44)
+	input.SetStyles(textinput.DefaultStyles(true))
 	return ExportModal{textInput: input}
 }
 
@@ -26,6 +27,12 @@ func (m ExportModal) Visible() bool {
 	return m.visible
 }
 
+// SetDarkMode updates export modal text input styles.
+func (m ExportModal) SetDarkMode(isDark bool) ExportModal {
+	m.textInput.SetStyles(textinput.DefaultStyles(isDark))
+	return m
+}
+
 func (m ExportModal) Open(defaultName string) ExportModal {
 	m.visible = true
 	m.err = ""
diff --git a/internal/tui/eventstream/filtermodal.go b/internal/tui/eventstream/filtermodal.go
index 6c7653e..bd20a03 100644
--- a/internal/tui/eventstream/filtermodal.go
+++ b/internal/tui/eventstream/filtermodal.go
@@ -49,6 +49,7 @@ func NewFilterModal() FilterModal {
 	input.Prompt = ""
 	input.CharLimit = 0
 	input.SetWidth(24)
+	input.SetStyles(textinput.DefaultStyles(true))
 
 	m := FilterModal{textInput: input}
 	m.fields = defaultFilterFields()
@@ -63,6 +64,12 @@ func (m FilterModal) Filter() Filter {
 	return m.filter
 }
 
+// SetDarkMode updates filter modal text input styles.
+func (m FilterModal) SetDarkMode(isDark bool) FilterModal {
+	m.textInput.SetStyles(textinput.DefaultStyles(isDark))
+	return m
+}
+
 func (m FilterModal) Open(initial Filter) FilterModal {
 	m.visible = true
 	m.activeField = 0
diff --git a/internal/tui/eventstream/model.go b/internal/tui/eventstream/model.go
index af7f67d..68b0cd5 100644
--- a/internal/tui/eventstream/model.go
+++ b/internal/tui/eventstream/model.go
@@ -53,6 +53,7 @@ type Model struct {
 	pendingOpenPath   string
 	statusMessage     string
 	exportDir         string
+	isDark            bool
 
 	width  int
 	height int
@@ -69,7 +70,7 @@ type fdTraceViewState struct {
 }
 
 func NewModel(source *RingBuffer) Model {
-	return Model{
+	m := Model{
 		source:      source,
 		filterModal: NewFilterModal(),
 		exportModal: NewExportModal(),
@@ -79,7 +80,10 @@ func NewModel(source *RingBuffer) Model {
 		selectedCol: 0,
 		exportDir:   ".",
 		showFooter:  true,
+		isDark:      true,
 	}
+	m.SetDarkMode(true)
+	return m
 }
 
 // SetViewport updates the render/scroll viewport dimensions used for
@@ -104,6 +108,14 @@ func (m *Model) SetSource(source *RingBuffer) {
 	m.Refresh()
 }
 
+// SetDarkMode updates stream modal text input styles for the active theme.
+func (m *Model) SetDarkMode(isDark bool) {
+	m.isDark = isDark
+	m.filterModal = m.filterModal.SetDarkMode(isDark)
+	m.exportModal = m.exportModal.SetDarkMode(isDark)
+	m.searchModal = m.searchModal.SetDarkMode(isDark)
+}
+
 // FilterModalVisible reports whether the filter modal is currently open.
 func (m Model) FilterModalVisible() bool {
 	return m.filterModal.Visible()
diff --git a/internal/tui/eventstream/searchmodal.go b/internal/tui/eventstream/searchmodal.go
index 892b6d9..c09542b 100644
--- a/internal/tui/eventstream/searchmodal.go
+++ b/internal/tui/eventstream/searchmodal.go
@@ -27,6 +27,7 @@ func NewSearchModal() SearchModal {
 	input.Prompt = ""
 	input.CharLimit = 0
 	input.SetWidth(44)
+	input.SetStyles(textinput.DefaultStyles(true))
 	return SearchModal{textInput: input, direction: SearchForward}
 }
 
@@ -38,6 +39,12 @@ func (m SearchModal) Direction() SearchDirection {
 	return m.direction
 }
 
+// SetDarkMode updates search modal text input styles.
+func (m SearchModal) SetDarkMode(isDark bool) SearchModal {
+	m.textInput.SetStyles(textinput.DefaultStyles(isDark))
+	return m
+}
+
 func (m SearchModal) Open(direction SearchDirection, defaultTerm string) SearchModal {
 	m.visible = true
 	m.err = ""
diff --git a/internal/tui/pidpicker/model.go b/internal/tui/pidpicker/model.go
index 187be52..87c200c 100644
--- a/internal/tui/pidpicker/model.go
+++ b/internal/tui/pidpicker/model.go
@@ -50,6 +50,14 @@ var (
 	errorStyle     = common.ErrorStyle
 )
 
+func syncPickerStyles() {
+	screenStyle = common.ScreenStyle
+	headerStyle = common.HeaderStyle
+	helpBarStyle = common.HelpBarStyle
+	highlightStyle = common.HighlightStyle
+	errorStyle = common.ErrorStyle
+}
+
 type processesLoadedMsg struct {
 	processes []ProcessInfo
 	err       error
@@ -67,6 +75,7 @@ type Model struct {
 	height        int
 	keys          KeyMap
 	lastErr       error
+	isDark        bool
 }
 
 // New creates a PID picker model with default shared key bindings.
@@ -81,12 +90,14 @@ func NewWithKeys(keys KeyMap) Model {
 
 // NewPIDWithKeys creates a PID picker model with the provided key bindings.
 func NewPIDWithKeys(keys KeyMap) Model {
+	syncPickerStyles()
 	input := textinput.New()
 	input.Prompt = "Filter: "
 	input.Placeholder = "pid, comm, or cmdline"
 	input.Focus()
 	input.CharLimit = 0
 	input.SetWidth(40)
+	input.SetStyles(textinput.DefaultStyles(true))
 
 	return Model{
 		input:     input,
@@ -94,6 +105,7 @@ func NewPIDWithKeys(keys KeyMap) Model {
 		filtered:  []ProcessInfo{},
 		mode:      PickerModePID,
 		targetPID: -1,
+		isDark:    true,
 	}
 }
 
@@ -268,6 +280,14 @@ func (m Model) View() tea.View {
 	return tea.NewView(screenStyle.Render(b.String()))
 }
 
+// SetDarkMode updates picker theme and text input styles.
+func (m Model) SetDarkMode(isDark bool) Model {
+	m.isDark = isDark
+	syncPickerStyles()
+	m.input.SetStyles(textinput.DefaultStyles(isDark))
+	return m
+}
+
 func (m Model) renderRows() string {
 	lines := make([]string, 0, len(m.filtered)+1)
 	allLabel := allPIDsLabel
diff --git a/internal/tui/probes/model.go b/internal/tui/probes/model.go
index c4512f9..7da27db 100644
--- a/internal/tui/probes/model.go
+++ b/internal/tui/probes/model.go
@@ -39,6 +39,7 @@ type Model struct {
 	lastErr string
 	manager Manager
 	height  int
+	isDark  bool
 }
 
 func NewModel(manager Manager) Model {
@@ -46,9 +47,11 @@ func NewModel(manager Manager) Model {
 	ti.Prompt = "/ "
 	ti.CharLimit = 0
 	ti.SetWidth(28)
+	ti.SetStyles(textinput.DefaultStyles(true))
 	return Model{
 		manager:   manager,
 		textInput: ti,
+		isDark:    true,
 	}
 }
 
@@ -72,6 +75,13 @@ func (m Model) Close() Model {
 	return m
 }
 
+// SetDarkMode updates probe modal text input styles.
+func (m Model) SetDarkMode(isDark bool) Model {
+	m.isDark = isDark
+	m.textInput.SetStyles(textinput.DefaultStyles(isDark))
+	return m
+}
+
 func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
 	if !m.visible {
 		return m, nil
diff --git a/internal/tui/styles.go b/internal/tui/styles.go
index 3bf69f7..9f7a16a 100644
--- a/internal/tui/styles.go
+++ b/internal/tui/styles.go
@@ -38,3 +38,26 @@ var (
 	// ErrorStyle is used for fatal or warning messages.
 	ErrorStyle = common.ErrorStyle
 )
+
+func syncStylesFromCommon() {
+	ColorBackground = common.ColorBackground
+	ColorPanel = common.ColorPanel
+	ColorPrimary = common.ColorPrimary
+	ColorAccent = common.ColorAccent
+	ColorMuted = common.ColorMuted
+	ColorText = common.ColorText
+	ColorDanger = common.ColorDanger
+
+	ScreenStyle = common.ScreenStyle
+	HeaderStyle = common.HeaderStyle
+	TabActiveStyle = common.TabActiveStyle
+	TabInactiveStyle = common.TabInactiveStyle
+	PanelStyle = common.PanelStyle
+	HelpBarStyle = common.HelpBarStyle
+	HighlightStyle = common.HighlightStyle
+	ErrorStyle = common.ErrorStyle
+}
+
+func init() {
+	syncStylesFromCommon()
+}
diff --git a/internal/tui/tui.go b/internal/tui/tui.go
index 6c08c2f..a12554a 100644
--- a/internal/tui/tui.go
+++ b/internal/tui/tui.go
@@ -173,6 +173,7 @@ type Model struct {
 
 	pidFilter     int
 	exportEnabled bool
+	isDark        bool
 }
 
 // NewModel creates the top-level TUI model.
@@ -182,6 +183,9 @@ func NewModel(initialPID int, startTrace TraceStarter) Model {
 }
 
 func newModelWithRuntimeConfig(initialPID, startupPidFilter int, exportEnabled bool, startTrace TraceStarter) Model {
+	common.ApplyPalette(true)
+	syncStylesFromCommon()
+
 	spin := spinner.New()
 	spin.Spinner = spinner.MiniDot
 	if startTrace == nil {
@@ -194,6 +198,7 @@ func newModelWithRuntimeConfig(initialPID, startupPidFilter int, exportEnabled b
 
 	runtime := newRuntimeBindings()
 	dashboard := dashboardui.NewModelWithConfig(lateBoundDashboardSource{runtime: runtime}, runtime.eventStreamSource(), 1000, keys)
+	dashboard.SetDarkMode(true)
 	pidFilter := selectedPIDFilter(startupPidFilter)
 	if initialPID > 0 {
 		pidFilter = selectedPIDFilter(initialPID)
@@ -202,16 +207,17 @@ func newModelWithRuntimeConfig(initialPID, startupPidFilter int, exportEnabled b
 
 	model := Model{
 		screen:        ScreenPIDPicker,
-		pidPicker:     pidpicker.New(),
+		pidPicker:     pidpicker.New().SetDarkMode(true),
 		dashboard:     dashboard,
 		exporter:      tuiexport.NewModel(),
-		probeModal:    probes.NewModel(runtime.currentProbeManager()),
+		probeModal:    probes.NewModel(runtime.currentProbeManager()).SetDarkMode(true),
 		runtime:       runtime,
 		keys:          keys,
 		spin:          spin,
 		startTrace:    startTrace,
 		pidFilter:     pidFilter,
 		exportEnabled: exportEnabled,
+		isDark:        true,
 	}
 
 	if initialPID > 0 {
@@ -227,9 +233,9 @@ func newModelWithRuntimeConfig(initialPID, startupPidFilter int, exportEnabled b
 func (m Model) Init() tea.Cmd {
 	sizeCmd := initialWindowSizeCmd()
 	if m.screen == ScreenDashboard && m.attaching {
-		return tea.Batch(sizeCmd, tea.RequestWindowSize, m.spin.Tick, m.beginTraceCmd())
+		return tea.Batch(sizeCmd, tea.RequestWindowSize, tea.RequestBackgroundColor, m.spin.Tick, m.beginTraceCmd())
 	}
-	return tea.Batch(sizeCmd, tea.RequestWindowSize, m.pidPicker.Init())
+	return tea.Batch(sizeCmd, tea.RequestWindowSize, tea.RequestBackgroundColor, m.pidPicker.Init())
 }
 
 func initialWindowSizeCmd() tea.Cmd {
@@ -246,6 +252,9 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		m.width = msg.Width
 		m.height = msg.Height
 		return m.updateActiveModel(msg)
+	case tea.BackgroundColorMsg:
+		m.applyTheme(msg.IsDark())
+		return m, nil
 	case tea.KeyPressMsg:
 		if key.Matches(msg, m.keys.Quit) {
 			m.quitting = true
@@ -257,7 +266,7 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			return m, nil
 		}
 		if m.screen == ScreenDashboard && !m.attaching && m.lastErr == nil && key.Matches(msg, m.keys.Probes) && !m.exporter.Visible() && !m.probeModal.Visible() && !m.dashboard.BlocksGlobalShortcuts() {
-			m.probeModal = probes.NewModel(m.runtime.currentProbeManager()).Open()
+			m.probeModal = probes.NewModel(m.runtime.currentProbeManager()).SetDarkMode(m.isDark).Open()
 			return m, nil
 		}
 		if m.screen == ScreenDashboard && !m.attaching && m.lastErr == nil && key.Matches(msg, m.keys.SelectPID) && !m.exporter.Visible() && !m.probeModal.Visible() && !m.dashboard.BlocksGlobalShortcuts() {
@@ -383,8 +392,8 @@ func (m Model) reselectPID() (tea.Model, tea.Cmd) {
 	m.attaching = false
 	m.lastErr = nil
 	m.exporter = tuiexport.NewModel()
-	m.probeModal = probes.NewModel(m.runtime.currentProbeManager())
-	m.pidPicker = pidpicker.New()
+	m.probeModal = probes.NewModel(m.runtime.currentProbeManager()).SetDarkMode(m.isDark)
+	m.pidPicker = pidpicker.New().SetDarkMode(m.isDark)
 
 	var sizeCmd tea.Cmd
 	if m.width > 0 && m.height > 0 {
@@ -404,8 +413,8 @@ func (m Model) reselectTID() (tea.Model, tea.Cmd) {
 	m.attaching = false
 	m.lastErr = nil
 	m.exporter = tuiexport.NewModel()
-	m.probeModal = probes.NewModel(m.runtime.currentProbeManager())
-	m.pidPicker = pidpicker.NewTIDWithKeys(pid, pidpicker.DefaultKeyMap())
+	m.probeModal = probes.NewModel(m.runtime.currentProbeManager()).SetDarkMode(m.isDark)
+	m.pidPicker = pidpicker.NewTIDWithKeys(pid, pidpicker.DefaultKeyMap()).SetDarkMode(m.isDark)
 
 	var sizeCmd tea.Cmd
 	if m.width > 0 && m.height > 0 {
@@ -454,6 +463,18 @@ func (m *Model) stopTrace() {
 	}
 }
 
+func (m *Model) applyTheme(isDark bool) {
+	if m.isDark == isDark {
+		return
+	}
+	m.isDark = isDark
+	common.ApplyPalette(isDark)
+	syncStylesFromCommon()
+	m.dashboard.SetDarkMode(isDark)
+	m.pidPicker = m.pidPicker.SetDarkMode(isDark)
+	m.probeModal = m.probeModal.SetDarkMode(isDark)
+}
+
 // View renders the currently active screen and startup overlay state.
 func (m Model) View() tea.View {
 	if m.quitting {