diff --git a/internal/app/application.go b/internal/app/application.go
deleted file mode 100644
index 95c809c..0000000
--- a/internal/app/application.go
+++ /dev/null
@@ -1,326 +0,0 @@
-package app
-
-import (
-	"github.com/gdamore/tcell/v2"
-	"github.com/nebara/nebara-os/internal/ui/components"
-	"github.com/nebara/nebara-os/internal/ui/layout"
-	"github.com/nebara/nebara-os/internal/ui/theme"
-	"github.com/rivo/tview"
-)
-
-// Application is the root Nebara OS TUI application object.
-// It owns the tview application, all UI components, and the application state.
-type Application struct {
-	tviewApp *tview.Application
-	state    *State
-
-	// tview layout primitives
-	pages       *tview.Pages
-	rootFlex    *tview.Flex // full-screen outer flex
-	contentFlex *tview.Flex // inner vertical flex with margins applied
-
-	// Named UI components
-	header      *components.HeaderWidget
-	appInfo     *components.ApplianceInfoWidget
-	msgWidget   *components.MessageWidget
-	menuWidget  *components.MenuWidget
-	description *components.DescriptionWidget
-	footer      *components.FooterWidget
-
-	// Current layout constraints
-	constraints layout.Constraints
-
-	// Minimum-size overlay: when true we only show the size warning.
-	tooSmall bool
-}
-
-// NewApplication constructs the complete TUI application from application state.
-func NewApplication(state *State) *Application {
-	a := &Application{
-		tviewApp: tview.NewApplication(),
-		state:    state,
-	}
-	a.tviewApp.EnableMouse(false)
-	a.buildUI()
-	a.wireCallbacks()
-	a.syncDescription()
-	return a
-}
-
-// Run starts the TUI event loop and blocks until the application exits.
-func (a *Application) Run() error {
-	return a.tviewApp.Run()
-}
-
-// buildUI constructs all widgets and assembles the layout.
-func (a *Application) buildUI() {
-	s := a.state
-
-	// --- Widgets ---
-	a.header = components.NewHeaderWidget(s.Appliance.Version, 8)
-	a.appInfo = components.NewApplianceInfoWidget(s.Appliance)
-	a.msgWidget = components.NewMessageWidget()
-	a.msgWidget.SetMessage(s.Message)
-
-	// Determine initial inner padding for menu.
-	a.menuWidget = components.NewMenuWidget(
-		a.state.Navigator.Current().Items,
-		2,
-	)
-	a.menuWidget.SetSelectedIndex(a.state.Navigator.Current().SelectedIdx)
-
-	a.description = components.NewDescriptionWidget()
-	a.footer = components.NewFooterWidget()
-
-	// --- Assemble layout ---
-	a.contentFlex = a.buildContentFlex()
-
-	// Outer flex: left margin | content | right margin
-	a.rootFlex = tview.NewFlex().SetDirection(tview.FlexColumn)
-	a.rootFlex.SetBackgroundColor(theme.ColorBackground)
-
-	a.pages = tview.NewPages()
-	a.pages.SetBackgroundColor(theme.ColorBackground)
-	a.pages.AddPage("main", a.rootFlex, true, true)
-
-	// Initial layout pass — will be recalculated on first draw/resize.
-	a.applyConstraints(layout.Calculate(120, 40))
-
-	a.tviewApp.SetRoot(a.pages, true)
-	a.tviewApp.SetFocus(a.menuWidget)
-
-	// Handle terminal resize.
-	a.tviewApp.SetBeforeDrawFunc(func(screen tcell.Screen) bool {
-		tw, th := screen.Size()
-		c := layout.Calculate(tw, th)
-		if c.IsMinimum != a.tooSmall ||
-			c.MarginH != a.constraints.MarginH ||
-			c.MarginV != a.constraints.MarginV ||
-			c.ContentWidth != a.constraints.ContentWidth {
-			a.applyConstraints(c)
-		}
-		return false
-	})
-
-	// Global key: Ctrl+C to quit, F1 for help.
-	a.tviewApp.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
-		switch event.Key() {
-		case tcell.KeyCtrlC:
-			a.tviewApp.Stop()
-			return nil
-		case tcell.KeyF1:
-			a.showHelp()
-			return nil
-		}
-		return event
-	})
-}
-
-// buildContentFlex assembles the vertical content stack (without outer margins).
-func (a *Application) buildContentFlex() *tview.Flex {
-	// Spacer utility.
-	spacer := func(rows int) tview.Primitive {
-		box := tview.NewBox().SetBackgroundColor(theme.ColorBackground)
-		_ = rows
-		return box
-	}
-
-	// Determine menu height: 2 rows per item (text + blank) + 2 border rows + 2 inset rows.
-	menuHeight := len(a.state.Navigator.Current().Items)*2 + 4
-
-	// Message row: always 1 row tall (hidden by making it 0 when not visible).
-	msgHeight := 0
-	if a.state.Message.IsVisible() {
-		msgHeight = 1
-	}
-
-	cf := tview.NewFlex().SetDirection(tview.FlexRow)
-	cf.SetBackgroundColor(theme.ColorBackground)
-
-	// Row 0: top vertical margin (spacer).
-	cf.AddItem(spacer(1), 1, 0, false) // placeholder; overridden in applyConstraints
-
-	// Row 1: Header.
-	cf.AddItem(a.header, 1, 0, false)
-
-	// Row 2: blank line after header.
-	cf.AddItem(spacer(1), 1, 0, false)
-
-	// Row 3: Appliance info block (product title + blank + 4 metadata rows = 6 rows).
-	cf.AddItem(a.appInfo, 6, 0, false)
-
-	// Row 4: Message row (0 or 1 row).
-	cf.AddItem(a.msgWidget, msgHeight, 0, false)
-
-	// Row 5: blank line before menu.
-	cf.AddItem(spacer(1), 1, 0, false)
-
-	// Row 6: Navigation menu.
-	cf.AddItem(a.menuWidget, menuHeight, 0, false)
-
-	// Row 7: Flexible whitespace — expands to consume remaining vertical space.
-	cf.AddItem(spacer(0), 0, 1, false)
-
-	// Row 8: Contextual description.
-	cf.AddItem(a.description, 1, 0, false)
-
-	// Row 9: blank between description and footer.
-	cf.AddItem(spacer(1), 1, 0, false)
-
-	// Row 10: Footer.
-	cf.AddItem(a.footer, 1, 0, false)
-
-	// Row 11: bottom vertical margin.
-	cf.AddItem(spacer(1), 1, 0, false)
-
-	return cf
-}
-
-// applyConstraints rebuilds margins and updates child widget parameters.
-func (a *Application) applyConstraints(c layout.Constraints) {
-	a.constraints = c
-	a.tooSmall = c.IsMinimum
-
-	// Clear and rebuild the outer flex.
-	a.rootFlex.Clear()
-	if c.IsMinimum {
-		// Show a minimal warning box.
-		warn := tview.NewBox().SetBackgroundColor(theme.ColorBackground)
-		a.rootFlex.AddItem(warn, 0, 1, false)
-		a.tviewApp.SetFocus(warn)
-		return
-	}
-
-	// Update header margin.
-	a.header.SetMarginH(c.MarginH)
-	a.header.Refresh(c.TermWidth)
-
-	// Update footer density.
-	a.footer.Refresh(c.TermWidth)
-
-	// Update menu inner padding.
-	a.menuWidget.SetInnerPad(c.MenuInnerPad)
-
-	// Update menu height based on current items.
-	menuItemCount := len(a.state.Navigator.Current().Items)
-	menuHeight := menuItemCount*2 + 4
-
-	// Message visibility.
-	msgHeight := 0
-	if a.state.Message.IsVisible() && c.MessageVisible {
-		msgHeight = 1
-	}
-
-	// Rebuild content flex items with updated sizes.
-	// We rebuild the whole content flex to keep sizing in sync.
-	a.contentFlex = a.rebuildContentFlex(c, menuHeight, msgHeight)
-
-	// Outer layout: left margin | content | right margin.
-	a.rootFlex.AddItem(tview.NewBox().SetBackgroundColor(theme.ColorBackground), c.MarginH, 0, false)
-	a.rootFlex.AddItem(a.contentFlex, 0, 1, true)
-	a.rootFlex.AddItem(tview.NewBox().SetBackgroundColor(theme.ColorBackground), c.MarginH, 0, false)
-
-	a.tviewApp.SetFocus(a.menuWidget)
-}
-
-// rebuildContentFlex constructs a fresh vertical flex with updated sizing.
-func (a *Application) rebuildContentFlex(c layout.Constraints, menuHeight, msgHeight int) *tview.Flex {
-	spacer := func() *tview.Box {
-		return tview.NewBox().SetBackgroundColor(theme.ColorBackground)
-	}
-
-	cf := tview.NewFlex().SetDirection(tview.FlexRow)
-	cf.SetBackgroundColor(theme.ColorBackground)
-
-	cf.AddItem(spacer(), c.MarginV, 0, false)
-	cf.AddItem(a.header, 1, 0, false)
-	cf.AddItem(spacer(), 1, 0, false)
-	cf.AddItem(a.appInfo, 6, 0, false)
-
-	if c.MessageVisible {
-		cf.AddItem(a.msgWidget, msgHeight, 0, false)
-	}
-
-	cf.AddItem(spacer(), 1, 0, false)
-	cf.AddItem(a.menuWidget, menuHeight, 0, true)
-	cf.AddItem(spacer(), 0, 1, false) // flexible whitespace
-	cf.AddItem(a.description, 1, 0, false)
-	cf.AddItem(spacer(), 1, 0, false)
-	cf.AddItem(a.footer, 1, 0, false)
-	cf.AddItem(spacer(), c.MarginV, 0, false)
-
-	return cf
-}
-
-// wireCallbacks connects navigation events to UI updates.
-func (a *Application) wireCallbacks() {
-	a.menuWidget.SetOnSelectionChanged(func(idx int) {
-		a.state.Navigator.Current().SelectedIdx = idx
-		a.syncDescription()
-	})
-
-	a.menuWidget.SetOnEnter(func(idx int) {
-		item := a.state.Navigator.SelectedItem()
-		if item == nil {
-			return
-		}
-		if !a.state.Navigator.Enter() {
-			// Leaf item — show not-implemented notice.
-			a.showNotImplemented(item.Label)
-			return
-		}
-		// Descended into submenu: refresh menu widget.
-		a.refreshMenuForCurrentLevel()
-	})
-
-	a.menuWidget.SetOnBack(func() {
-		if a.state.Navigator.Back() {
-			a.refreshMenuForCurrentLevel()
-		}
-	})
-}
-
-// refreshMenuForCurrentLevel updates the menu widget to reflect the current
-// navigation level and recalculates layout.
-func (a *Application) refreshMenuForCurrentLevel() {
-	cur := a.state.Navigator.Current()
-	a.menuWidget.SetItems(cur.Items)
-	a.menuWidget.SetSelectedIndex(cur.SelectedIdx)
-	a.syncDescription()
-	// Recalculate layout with new menu item count.
-	a.applyConstraints(a.constraints)
-}
-
-// syncDescription updates the contextual description for the selected item.
-func (a *Application) syncDescription() {
-	item := a.state.Navigator.SelectedItem()
-	if item == nil {
-		a.description.SetDescription("")
-		return
-	}
-	a.description.SetDescription(item.Description)
-}
-
-// showNotImplemented displays the not-implemented modal.
-func (a *Application) showNotImplemented(label string) {
-	modal := components.NewNotImplementedModal(label, func() {
-		a.pages.RemovePage("modal")
-		a.tviewApp.SetFocus(a.menuWidget)
-	})
-	a.pages.AddPage("modal", modal, true, true)
-	a.tviewApp.SetFocus(modal)
-}
-
-// showHelp displays the help modal.
-func (a *Application) showHelp() {
-	helpModal := components.HelpModal(func() {
-		a.pages.RemovePage("help")
-		a.tviewApp.SetFocus(a.menuWidget)
-	})
-	a.pages.AddPage("help", helpModal, true, true)
-	a.tviewApp.SetFocus(helpModal)
-}
-
-// SetInnerPad exposes the inner padding setter on MenuWidget for use by app.
-// (Defined here so app package can call it without modifying the component.)
-func init() {}
diff --git a/internal/app/state.go b/internal/app/state.go
deleted file mode 100644
index 74d3158..0000000
--- a/internal/app/state.go
+++ /dev/null
@@ -1,28 +0,0 @@
-// Package app wires together the Nebara OS TUI application.
-package app
-
-import (
-	"github.com/nebara/nebara-os/internal/mock"
-	"github.com/nebara/nebara-os/internal/model"
-	"github.com/nebara/nebara-os/internal/ui/navigation"
-)
-
-// State holds the complete runtime state of the TUI application.
-type State struct {
-	Appliance  model.ApplianceInfo
-	Message    *model.SystemMessage
-	Navigator  *navigation.Navigator
-	ShowModal  bool
-	ModalLabel string
-	ShowHelp   bool
-}
-
-// NewStateFromMock constructs application state from a mock scenario.
-func NewStateFromMock(s mock.State) *State {
-	nav := navigation.NewNavigator(model.MainMenu(), s.InitialMenu)
-	return &State{
-		Appliance: s.Appliance,
-		Message:   s.Message,
-		Navigator: nav,
-	}
-}
diff --git a/internal/mock/states.go b/internal/mock/states.go
deleted file mode 100644
index 9d9481c..0000000
--- a/internal/mock/states.go
+++ /dev/null
@@ -1,48 +0,0 @@
-// Package mock provides predefined appliance states for prototype validation.
-package mock
-
-import (
-	"github.com/nebara/nebara-os/internal/model"
-)
-
-// State bundles all data required to render a complete TUI screen.
-type State struct {
-	Appliance   model.ApplianceInfo
-	Message     *model.SystemMessage
-	InitialMenu int // zero-based index into model.MainMenu()
-}
-
-// WarningState reproduces Figma mock state A.
-func WarningState() State {
-	return State{
-		Appliance: model.ApplianceInfo{
-			ProductName: "Nebara S3GX Appliance",
-			Version:     "1.0.1",
-			Hostname:    "jkt-s3gx-lin-01.domain.local",
-			Address:     "10.249.23.13/26",
-			Uptime:      "132d 12h 32m",
-			Status:      "Healthy",
-		},
-		Message: &model.SystemMessage{
-			Severity: model.SeverityWarning,
-			Text:     "[Warn] Update Available to version 2.1.4!",
-		},
-		InitialMenu: 2, // Security & Access
-	}
-}
-
-// NormalState reproduces Figma mock state B.
-func NormalState() State {
-	return State{
-		Appliance: model.ApplianceInfo{
-			ProductName: "Nebara S3GX Appliance",
-			Version:     "2.1.4",
-			Hostname:    "sin-s3gx-lin-05.domain.local",
-			Address:     "10.175.15.11/25",
-			Uptime:      "111d 14h 21m",
-			Status:      "Healthy",
-		},
-		Message:     nil,
-		InitialMenu: 3, // System Maintenance
-	}
-}
diff --git a/internal/mock/states_test.go b/internal/mock/states_test.go
deleted file mode 100644
index 55fbc68..0000000
--- a/internal/mock/states_test.go
+++ /dev/null
@@ -1,91 +0,0 @@
-package mock_test
-
-import (
-	"testing"
-
-	"github.com/nebara/nebara-os/internal/mock"
-	"github.com/nebara/nebara-os/internal/model"
-)
-
-func TestWarningState(t *testing.T) {
-	s := mock.WarningState()
-
-	if s.Appliance.ProductName == "" {
-		t.Error("ProductName should not be empty")
-	}
-	if s.Appliance.Version != "1.0.1" {
-		t.Errorf("expected version 1.0.1, got %s", s.Appliance.Version)
-	}
-	if s.Message == nil {
-		t.Fatal("warning state should have a message")
-	}
-	if s.Message.Severity != model.SeverityWarning {
-		t.Error("expected SeverityWarning")
-	}
-	if !s.Message.IsVisible() {
-		t.Error("warning message should be visible")
-	}
-	if s.InitialMenu < 0 || s.InitialMenu >= 6 {
-		t.Errorf("InitialMenu out of range: %d", s.InitialMenu)
-	}
-}
-
-func TestNormalState(t *testing.T) {
-	s := mock.NormalState()
-
-	if s.Appliance.ProductName == "" {
-		t.Error("ProductName should not be empty")
-	}
-	if s.Appliance.Version != "2.1.4" {
-		t.Errorf("expected version 2.1.4, got %s", s.Appliance.Version)
-	}
-	if s.Message != nil && s.Message.IsVisible() {
-		t.Error("normal state should have no visible message")
-	}
-	if s.InitialMenu < 0 || s.InitialMenu >= 6 {
-		t.Errorf("InitialMenu out of range: %d", s.InitialMenu)
-	}
-}
-
-func TestWarningState_CorrectMenuSelection(t *testing.T) {
-	s := mock.WarningState()
-	menu := model.MainMenu()
-	if s.InitialMenu >= len(menu) {
-		t.Fatalf("InitialMenu %d exceeds menu length %d", s.InitialMenu, len(menu))
-	}
-	if menu[s.InitialMenu].Label != "Security & Access" {
-		t.Errorf("warning state should select 'Security & Access', got %q", menu[s.InitialMenu].Label)
-	}
-}
-
-func TestNormalState_CorrectMenuSelection(t *testing.T) {
-	s := mock.NormalState()
-	menu := model.MainMenu()
-	if s.InitialMenu >= len(menu) {
-		t.Fatalf("InitialMenu %d exceeds menu length %d", s.InitialMenu, len(menu))
-	}
-	if menu[s.InitialMenu].Label != "System Maintenance" {
-		t.Errorf("normal state should select 'System Maintenance', got %q", menu[s.InitialMenu].Label)
-	}
-}
-
-func TestSystemMessage_IsVisible_Nil(t *testing.T) {
-	var m *model.SystemMessage
-	if m.IsVisible() {
-		t.Error("nil message should not be visible")
-	}
-}
-
-func TestSystemMessage_IsVisible_Empty(t *testing.T) {
-	m := &model.SystemMessage{Severity: model.SeverityWarning, Text: ""}
-	if m.IsVisible() {
-		t.Error("empty text message should not be visible")
-	}
-}
-
-func TestSystemMessage_IsVisible_SeverityNone(t *testing.T) {
-	m := &model.SystemMessage{Severity: model.SeverityNone, Text: "some text"}
-	if m.IsVisible() {
-		t.Error("SeverityNone message should not be visible")
-	}
-}
diff --git a/internal/model/appliance.go b/internal/model/appliance.go
deleted file mode 100644
index 60cb53c..0000000
--- a/internal/model/appliance.go
+++ /dev/null
@@ -1,12 +0,0 @@
-// Package model defines the data structures for the Nebara OS TUI.
-package model
-
-// ApplianceInfo holds the display data for the appliance information section.
-type ApplianceInfo struct {
-	ProductName string
-	Version     string
-	Hostname    string
-	Address     string
-	Uptime      string
-	Status      string
-}
diff --git a/internal/model/menu.go b/internal/model/menu.go
deleted file mode 100644
index b503e45..0000000
--- a/internal/model/menu.go
+++ /dev/null
@@ -1,82 +0,0 @@
-package model
-
-// MenuItem represents a single entry in any menu level.
-type MenuItem struct {
-	Label       string
-	Description string
-	Children    []MenuItem
-}
-
-// MainMenu returns the complete main menu data structure.
-func MainMenu() []MenuItem {
-	return []MenuItem{
-		{
-			Label:       "System Configuration",
-			Description: "Configure appliance hostname, system identity, time and general settings.",
-			Children: []MenuItem{
-				{Label: "Hostname & Domain", Description: "Configure the appliance hostname and domain name."},
-				{Label: "Date & Time", Description: "Set the system date and time."},
-				{Label: "NTP Configuration", Description: "Configure Network Time Protocol servers."},
-				{Label: "System Information", Description: "View system hardware and software information."},
-				{Label: "Appliance Identity", Description: "Configure appliance identity and asset tags."},
-			},
-		},
-		{
-			Label:       "Network Configuration",
-			Description: "Configure management interfaces, IP addressing, DNS and network connectivity.",
-			Children: []MenuItem{
-				{Label: "Management Interfaces", Description: "Configure management network interfaces."},
-				{Label: "IPv4 Configuration", Description: "Configure IPv4 addresses and subnet masks."},
-				{Label: "DNS Configuration", Description: "Configure DNS resolver settings."},
-				{Label: "Default Gateway & Routes", Description: "Configure default gateway and static routes."},
-				{Label: "VLAN Configuration", Description: "Configure VLAN tagging and interfaces."},
-				{Label: "Network Bonding", Description: "Configure interface bonding and aggregation."},
-				{Label: "Connectivity Test", Description: "Test network connectivity to targets."},
-			},
-		},
-		{
-			Label:       "Security & Access",
-			Description: "Manage user accounts, authentication and remote access.",
-			Children: []MenuItem{
-				{Label: "Local Users", Description: "Manage local user accounts."},
-				{Label: "Authentication Settings", Description: "Configure authentication methods."},
-				{Label: "Password Policy", Description: "Configure password complexity and expiry policies."},
-				{Label: "Remote Access", Description: "Configure SSH and remote management access."},
-				{Label: "Session Management", Description: "View and manage active sessions."},
-			},
-		},
-		{
-			Label:       "System Maintenance",
-			Description: "Manage appliance updates, configuration backups and maintenance tasks.",
-			Children: []MenuItem{
-				{Label: "Appliance Updates", Description: "Check for and apply appliance software updates."},
-				{Label: "Configuration Backup", Description: "Back up the current appliance configuration."},
-				{Label: "Configuration Restore", Description: "Restore appliance configuration from a backup."},
-				{Label: "System Restart", Description: "Safely restart the appliance."},
-				{Label: "System Shutdown", Description: "Safely shut down the appliance."},
-			},
-		},
-		{
-			Label:       "Diagnostics",
-			Description: "View system health, diagnostics and troubleshooting information.",
-			Children: []MenuItem{
-				{Label: "System Health", Description: "View overall system health status."},
-				{Label: "Hardware Information", Description: "View hardware component information."},
-				{Label: "Network Diagnostics", Description: "Run network diagnostic tools."},
-				{Label: "Service Status", Description: "View the status of system services."},
-				{Label: "System Logs", Description: "Browse and filter system log entries."},
-			},
-		},
-		{
-			Label:       "Support & Recovery",
-			Description: "Access support tools, recovery options and troubleshooting functions.",
-			Children: []MenuItem{
-				{Label: "Support Information", Description: "View support contact and licensing information."},
-				{Label: "Diagnostic Bundle", Description: "Generate a diagnostic bundle for support."},
-				{Label: "Recovery Options", Description: "Access factory reset and recovery options."},
-				{Label: "Troubleshooting Shell", Description: "Not available in this prototype."},
-				{Label: "Support Access", Description: "Manage remote support access credentials."},
-			},
-		},
-	}
-}
diff --git a/internal/model/message.go b/internal/model/message.go
deleted file mode 100644
index 5847089..0000000
--- a/internal/model/message.go
+++ /dev/null
@@ -1,23 +0,0 @@
-package model
-
-// MessageSeverity classifies the severity of a system message.
-type MessageSeverity int
-
-const (
-	// SeverityNone means no message is active.
-	SeverityNone MessageSeverity = iota
-	SeverityWarning
-	SeverityError
-	SeverityInfo
-)
-
-// SystemMessage represents an optional system-level status message.
-type SystemMessage struct {
-	Severity MessageSeverity
-	Text     string
-}
-
-// IsVisible returns true when there is an active message to display.
-func (m *SystemMessage) IsVisible() bool {
-	return m != nil && m.Severity != SeverityNone && m.Text != ""
-}
diff --git a/internal/ui/components/header.go b/internal/ui/components/header.go
deleted file mode 100644
index 7ce14fd..0000000
--- a/internal/ui/components/header.go
+++ /dev/null
@@ -1,266 +0,0 @@
-package components
-
-import (
-	"fmt"
-	"strings"
-
-	"github.com/gdamore/tcell/v2"
-	"github.com/nebara/nebara-os/internal/model"
-	"github.com/nebara/nebara-os/internal/ui/theme"
-	"github.com/rivo/tview"
-)
-
-// HeaderWidget renders the NEBARA - OS logo and version on the same row.
-// The "O" character in "OS" is rendered in the logo accent color (#B30D18).
-// All other characters use the primary foreground (#F5F5F5).
-//
-// Terminal limitation: tview.TextView supports color tags for mixed-color
-// text on a single line, which we use here.
-type HeaderWidget struct {
-	*tview.TextView
-	version string
-	marginH int
-}
-
-// NewHeaderWidget creates the header with the given version string and margin.
-func NewHeaderWidget(version string, marginH int) *HeaderWidget {
-	tv := tview.NewTextView().
-		SetDynamicColors(true).
-		SetScrollable(false)
-	tv.SetBackgroundColor(theme.ColorBackground)
-
-	h := &HeaderWidget{
-		TextView: tv,
-		version:  version,
-		marginH:  marginH,
-	}
-	h.refresh(80) // initial width estimate; recalculated on draw
-	return h
-}
-
-// SetVersion updates the version string and redraws.
-func (h *HeaderWidget) SetVersion(v string) {
-	h.version = v
-}
-
-// SetMarginH updates the horizontal margin.
-func (h *HeaderWidget) SetMarginH(m int) {
-	h.marginH = m
-}
-
-// Refresh recalculates the header text for the current terminal width.
-func (h *HeaderWidget) Refresh(termWidth int) {
-	h.refresh(termWidth)
-}
-
-func (h *HeaderWidget) refresh(termWidth int) {
-	// Logo: "NEBARA - OS" with "O" in accent red.
-	// tview color tag format: [#RRGGBB]
-	logoPlain := "NEBARA - "
-	// "O" accent, "S" back to primary
-	logoColored := fmt.Sprintf(
-		"[%s]%s[%s]O[%s]S",
-		theme.HexPrimary,
-		logoPlain,
-		theme.HexLogoAccent,
-		theme.HexPrimary,
-	)
-
-	versionText := "Version " + h.version
-
-	// The content width between the margins for text layout purposes.
-	// Visible character count for the logo is 11 ("NEBARA - OS").
-	// Visible character count for version: len("Version ") + len(version).
-	logoVisibleLen := len("NEBARA - OS")
-	versionVisibleLen := len(versionText)
-	contentWidth := termWidth - h.marginH*2
-
-	// Number of spaces between logo and version to right-align version.
-	spaces := contentWidth - logoVisibleLen - versionVisibleLen
-	if spaces < 1 {
-		spaces = 1
-	}
-
-	line := logoColored + strings.Repeat(" ", spaces) + versionText
-	h.TextView.SetText(line)
-}
-
-// ApplianceInfoWidget renders the appliance metadata block.
-type ApplianceInfoWidget struct {
-	*tview.TextView
-}
-
-// NewApplianceInfoWidget creates the appliance info display.
-func NewApplianceInfoWidget(info model.ApplianceInfo) *ApplianceInfoWidget {
-	tv := tview.NewTextView().
-		SetDynamicColors(true).
-		SetScrollable(false)
-	tv.SetBackgroundColor(theme.ColorBackground)
-
-	w := &ApplianceInfoWidget{TextView: tv}
-	w.SetInfo(info)
-	return w
-}
-
-// SetInfo refreshes the appliance information display.
-func (w *ApplianceInfoWidget) SetInfo(info model.ApplianceInfo) {
-	// Product title is bold; labels and values use regular weight.
-	// tview bold tag: [::b] ; reset: [::-]
-	text := fmt.Sprintf(
-		"[%s][::b]%s[::-]\n\n[%s]Hostname: %s\n[%s]Address : %s\n[%s]Uptime  : %s\n[%s]Status  : %s",
-		theme.HexPrimary, info.ProductName,
-		theme.HexPrimary, info.Hostname,
-		theme.HexPrimary, info.Address,
-		theme.HexPrimary, info.Uptime,
-		theme.HexPrimary, info.Status,
-	)
-	w.TextView.SetText(text)
-}
-
-// MessageWidget renders an optional severity-classified system message.
-type MessageWidget struct {
-	*tview.TextView
-}
-
-// NewMessageWidget creates the message widget (initially empty).
-func NewMessageWidget() *MessageWidget {
-	tv := tview.NewTextView().
-		SetDynamicColors(true).
-		SetScrollable(false)
-	tv.SetBackgroundColor(theme.ColorBackground)
-	return &MessageWidget{TextView: tv}
-}
-
-// SetMessage updates the displayed message. Pass nil to clear.
-func (w *MessageWidget) SetMessage(msg *model.SystemMessage) {
-	if msg == nil || !msg.IsVisible() {
-		w.TextView.SetText("")
-		return
-	}
-
-	var hexColor string
-	switch msg.Severity {
-	case model.SeverityWarning:
-		hexColor = theme.HexWarning
-	case model.SeverityError:
-		hexColor = theme.HexError
-	case model.SeverityInfo:
-		hexColor = theme.HexInfo
-	default:
-		hexColor = theme.HexPrimary
-	}
-
-	// "Message : " label in primary color, then the tagged text in severity color.
-	text := fmt.Sprintf("[%s]Message : [%s]%s",
-		theme.HexPrimary, hexColor, tview.Escape(msg.Text))
-	w.TextView.SetText(text)
-}
-
-// DescriptionWidget shows the contextual description for the selected menu item.
-type DescriptionWidget struct {
-	*tview.TextView
-}
-
-// NewDescriptionWidget creates the description area.
-func NewDescriptionWidget() *DescriptionWidget {
-	tv := tview.NewTextView().
-		SetDynamicColors(true).
-		SetScrollable(false).
-		SetWrap(true)
-	tv.SetBackgroundColor(theme.ColorBackground)
-	return &DescriptionWidget{TextView: tv}
-}
-
-// SetDescription updates the displayed contextual description.
-func (w *DescriptionWidget) SetDescription(text string) {
-	w.TextView.SetText(fmt.Sprintf("[%s]%s", theme.HexSecondary, tview.Escape(text)))
-}
-
-// FooterWidget renders the keyboard shortcut hint row.
-type FooterWidget struct {
-	*tview.TextView
-}
-
-// NewFooterWidget creates the keyboard hint footer.
-func NewFooterWidget() *FooterWidget {
-	tv := tview.NewTextView().
-		SetDynamicColors(true).
-		SetScrollable(false)
-	tv.SetBackgroundColor(theme.ColorBackground)
-
-	f := &FooterWidget{TextView: tv}
-	f.Refresh(120)
-	return f
-}
-
-// Refresh redraws the footer at the appropriate density for the terminal width.
-func (f *FooterWidget) Refresh(termWidth int) {
-	if termWidth < 80 {
-		// Compact form.
-		f.TextView.SetText(fmt.Sprintf("[%s][::b]↑↓[-] Nav  [::b]↵[-] Sel  [::b]Esc[-] Back  [::b]F1[-] Help",
-			theme.HexPrimary))
-	} else {
-		f.TextView.SetText(fmt.Sprintf("[%s][::b]↑↓[-] Navigate   [::b]Enter[-] [::b]Select[-]   [::b]Esc[-] [::b]Back[-]   [::b]F1[-] [::b]Help[-]",
-			theme.HexPrimary))
-	}
-}
-
-// ModalWidget is a simple centered dialog box for "not implemented" notices.
-type ModalWidget struct {
-	*tview.Modal
-}
-
-// NewNotImplementedModal creates a minimal "Not Implemented" modal.
-func NewNotImplementedModal(itemLabel string, onDismiss func()) *tview.Modal {
-	msg := fmt.Sprintf("[ %s ]\n\nThis function is not available in the\nNebara OS TUI Prototype v0.1.\n\nPress Enter or Escape to return.", itemLabel)
-	modal := tview.NewModal().
-		SetText(msg).
-		AddButtons([]string{"OK"}).
-		SetDoneFunc(func(_ int, _ string) {
-			if onDismiss != nil {
-				onDismiss()
-			}
-		})
-	modal.SetBackgroundColor(theme.ColorBackground)
-	modal.SetBorderColor(theme.ColorBorder)
-	modal.SetTextColor(theme.ColorSecondary)
-	return modal
-}
-
-// HelpModal returns a modal displaying keyboard shortcuts.
-func HelpModal(onDismiss func()) *tview.Modal {
-	text := "NEBARA OS — KEYBOARD SHORTCUTS\n\n" +
-		"↑ / ↓       Navigate menu items\n" +
-		"Enter       Open submenu / confirm\n" +
-		"Esc         Return to previous menu\n" +
-		"Home        Jump to first item\n" +
-		"End         Jump to last item\n" +
-		"F1          Show this help\n" +
-		"Ctrl+C      Quit application"
-	modal := tview.NewModal().
-		SetText(text).
-		AddButtons([]string{"Close"}).
-		SetDoneFunc(func(_ int, _ string) {
-			if onDismiss != nil {
-				onDismiss()
-			}
-		})
-	modal.SetBackgroundColor(theme.ColorBackground)
-	modal.SetBorderColor(theme.ColorBorder)
-	modal.SetTextColor(theme.ColorSecondary)
-	return modal
-}
-
-// MinSizeWarning renders a compact message when the terminal is too small.
-func MinSizeWarning(screen tcell.Screen, w, h int) {
-	msg := " Terminal too small. Minimum: 60×20 "
-	style := tcell.StyleDefault.Background(theme.ColorError).Foreground(theme.ColorBackground)
-	x := (w - len(msg)) / 2
-	y := h / 2
-	if x < 0 {
-		x = 0
-	}
-	for i, ch := range msg {
-		screen.SetContent(x+i, y, ch, nil, style)
-	}
-}
diff --git a/internal/ui/components/menu.go b/internal/ui/components/menu.go
deleted file mode 100644
index f4d4a97..0000000
--- a/internal/ui/components/menu.go
+++ /dev/null
@@ -1,211 +0,0 @@
-// Package components provides custom tview primitives for the Nebara OS TUI.
-// Each component is self-contained and themed using the centralized design system.
-package components
-
-import (
-	"github.com/gdamore/tcell/v2"
-	"github.com/nebara/nebara-os/internal/model"
-	"github.com/nebara/nebara-os/internal/ui/theme"
-	"github.com/rivo/tview"
-)
-
-// MenuWidget is a custom tview.Primitive that renders the navigation menu
-// with full-width row highlighting, a single-cell border, and inner padding.
-// It implements the exact Figma selection design: full-width BBBBBB background.
-type MenuWidget struct {
-	*tview.Box
-
-	items       []model.MenuItem
-	selectedIdx int
-	innerPad    int // horizontal cells of padding inside the border
-
-	// onSelectionChanged is called whenever the selected index changes.
-	onSelectionChanged func(idx int)
-	// onEnter is called when the user presses Enter on an item.
-	onEnter func(idx int)
-	// onBack is called when the user presses Escape.
-	onBack func()
-}
-
-// NewMenuWidget creates a MenuWidget with the given items and padding.
-func NewMenuWidget(items []model.MenuItem, innerPad int) *MenuWidget {
-	m := &MenuWidget{
-		Box:      tview.NewBox(),
-		items:    items,
-		innerPad: innerPad,
-	}
-	m.Box.SetBackgroundColor(theme.ColorBackground)
-	m.Box.SetBorderColor(theme.ColorBorder)
-	m.Box.SetBorder(true)
-	return m
-}
-
-// SetInnerPad updates the horizontal padding inside the border.
-func (m *MenuWidget) SetInnerPad(pad int) {
-	m.innerPad = pad
-}
-
-// SetItems replaces the current menu items.
-func (m *MenuWidget) SetItems(items []model.MenuItem) {
-	m.items = items
-	if m.selectedIdx >= len(items) {
-		m.selectedIdx = 0
-	}
-}
-
-// SetSelectedIndex sets the highlighted row.
-func (m *MenuWidget) SetSelectedIndex(idx int) {
-	if idx >= 0 && idx < len(m.items) {
-		m.selectedIdx = idx
-	}
-}
-
-// SelectedIndex returns the current highlighted row index.
-func (m *MenuWidget) SelectedIndex() int {
-	return m.selectedIdx
-}
-
-// SetOnSelectionChanged registers a callback invoked on selection movement.
-func (m *MenuWidget) SetOnSelectionChanged(fn func(int)) {
-	m.onSelectionChanged = fn
-}
-
-// SetOnEnter registers a callback invoked when Enter is pressed.
-func (m *MenuWidget) SetOnEnter(fn func(int)) {
-	m.onEnter = fn
-}
-
-// SetOnBack registers a callback invoked when Escape is pressed.
-func (m *MenuWidget) SetOnBack(fn func()) {
-	m.onBack = fn
-}
-
-// Draw renders the menu widget.
-// The border is drawn by tview.Box; we draw the items in the inner area.
-func (m *MenuWidget) Draw(screen tcell.Screen) {
-	// Draw the box border first.
-	m.Box.Draw(screen)
-
-	// Get the inner area (inside the border).
-	x, y, w, h := m.Box.GetInnerRect()
-	if w <= 0 || h <= 0 {
-		return
-	}
-
-	// Render each item. Each item occupies exactly one row with one blank row
-	// between items for visual breathing room, matching the Figma layout.
-	// We use a 1-cell vertical inset inside the border (top and bottom).
-	innerY := y + 1 // 1-cell top inset
-	innerH := h - 2 // reserve 1-cell bottom inset
-	_ = innerH
-
-	for i, item := range m.items {
-		row := innerY + i*2 // 2 rows per item: text + blank separator
-		if row >= y+h-1 {
-			break // do not overflow the border bottom
-		}
-
-		isSelected := i == m.selectedIdx
-
-		var fg, bg tcell.Color
-		var bold bool
-		if isSelected {
-			fg = theme.ColorSelectionFg
-			bg = theme.ColorSelectionBg
-			bold = false
-		} else {
-			fg = theme.ColorPrimary
-			bg = theme.ColorBackground
-			bold = false
-		}
-
-		style := tcell.StyleDefault.Background(bg).Foreground(fg)
-		if bold {
-			style = style.Bold(true)
-		}
-
-		// Build the label: ">" prefix for selected, "  " otherwise.
-		prefix := "  "
-		if isSelected {
-			prefix = "> "
-		}
-		label := prefix + item.Label
-
-		// Fill the entire row width with the selection background.
-		// This gives the full-width highlight shown in the mockup.
-		fillRow(screen, x, row, w, style)
-
-		// Draw the label text (with left padding inside the border).
-		textX := x + m.innerPad
-		drawText(screen, textX, row, label, style)
-	}
-}
-
-// InputHandler handles keyboard events for the menu widget.
-func (m *MenuWidget) InputHandler() func(event *tcell.EventKey, setFocus func(p tview.Primitive)) {
-	return m.WrapInputHandler(func(event *tcell.EventKey, setFocus func(p tview.Primitive)) {
-		switch event.Key() {
-		case tcell.KeyUp:
-			if m.selectedIdx > 0 {
-				m.selectedIdx--
-				if m.onSelectionChanged != nil {
-					m.onSelectionChanged(m.selectedIdx)
-				}
-			}
-		case tcell.KeyDown:
-			if m.selectedIdx < len(m.items)-1 {
-				m.selectedIdx++
-				if m.onSelectionChanged != nil {
-					m.onSelectionChanged(m.selectedIdx)
-				}
-			}
-		case tcell.KeyHome:
-			if m.selectedIdx != 0 {
-				m.selectedIdx = 0
-				if m.onSelectionChanged != nil {
-					m.onSelectionChanged(m.selectedIdx)
-				}
-			}
-		case tcell.KeyEnd:
-			last := len(m.items) - 1
-			if m.selectedIdx != last {
-				m.selectedIdx = last
-				if m.onSelectionChanged != nil {
-					m.onSelectionChanged(m.selectedIdx)
-				}
-			}
-		case tcell.KeyEnter:
-			if m.onEnter != nil {
-				m.onEnter(m.selectedIdx)
-			}
-		case tcell.KeyEscape:
-			if m.onBack != nil {
-				m.onBack()
-			}
-		}
-	})
-}
-
-// HasFocus is required to satisfy tview.Primitive.
-func (m *MenuWidget) HasFocus() bool {
-	return m.Box.HasFocus()
-}
-
-// Focus is required to satisfy tview.Primitive.
-func (m *MenuWidget) Focus(delegate func(p tview.Primitive)) {
-	m.Box.Focus(delegate)
-}
-
-// fillRow paints an entire horizontal row with the given style.
-func fillRow(screen tcell.Screen, x, y, width int, style tcell.Style) {
-	for col := x; col < x+width; col++ {
-		screen.SetContent(col, y, ' ', nil, style)
-	}
-}
-
-// drawText writes a string starting at (x, y) using the given style.
-func drawText(screen tcell.Screen, x, y int, text string, style tcell.Style) {
-	for i, ch := range text {
-		screen.SetContent(x+i, y, ch, nil, style)
-	}
-}
diff --git a/internal/ui/layout/responsive.go b/internal/ui/layout/responsive.go
deleted file mode 100644
index d14b318..0000000
--- a/internal/ui/layout/responsive.go
+++ /dev/null
@@ -1,93 +0,0 @@
-// Package layout provides responsive dimension calculations for the Nebara OS TUI.
-// All functions operate on terminal cell dimensions, not pixels.
-package layout
-
-// Constraints holds calculated layout values for a given terminal size.
-type Constraints struct {
-	TermWidth  int
-	TermHeight int
-
-	// Outer horizontal margin in cells (applied to both left and right sides).
-	MarginH int
-	// Outer vertical margin in cells (applied to top and bottom).
-	MarginV int
-
-	// ContentWidth is the usable width between the two horizontal margins.
-	ContentWidth int
-
-	// AppInfoLines is the number of rows reserved for appliance information
-	// (product title + 4 metadata rows).
-	AppInfoLines int
-
-	// MessageVisible indicates whether the message row should be shown.
-	// On very compact terminals it may be suppressed.
-	MessageVisible bool
-
-	// MenuInnerPad is the horizontal padding inside the menu border.
-	MenuInnerPad int
-
-	// FooterLines is the number of rows occupied by the footer (description + shortcuts).
-	FooterLines int
-
-	// IsMinimum flags terminals smaller than the supported minimum.
-	IsMinimum bool
-}
-
-// MinWidth is the smallest terminal width the application supports gracefully.
-const MinWidth = 60
-
-// MinHeight is the smallest terminal height the application supports gracefully.
-const MinHeight = 20
-
-// Calculate derives layout constraints from terminal dimensions.
-// Reference: Figma frame 1920×1080 with 80px outer margins (4.17% of width)
-// and 60px vertical margins (5.56% of height).
-func Calculate(termW, termH int) Constraints {
-	if termW < MinWidth || termH < MinHeight {
-		return Constraints{
-			TermWidth:  termW,
-			TermHeight: termH,
-			IsMinimum:  true,
-		}
-	}
-
-	// Horizontal margin: ~4.17% of width, min 4 cells, max 12 cells.
-	marginH := clamp(termW*417/10000, 4, 12)
-
-	// Vertical margin: ~5.56% of height, min 1 cell, max 4 cells.
-	marginV := clamp(termH*556/10000, 1, 4)
-
-	contentWidth := termW - marginH*2
-
-	// Menu inner horizontal padding (space between border char and text).
-	menuInnerPad := 2
-	if termW < 100 {
-		menuInnerPad = 1
-	}
-
-	// Message row visibility: suppress on very compact terminals.
-	messageVisible := termH >= 24
-
-	return Constraints{
-		TermWidth:      termW,
-		TermHeight:     termH,
-		MarginH:        marginH,
-		MarginV:        marginV,
-		ContentWidth:   contentWidth,
-		AppInfoLines:   6, // blank + product title + blank + 4 metadata rows
-		MessageVisible: messageVisible,
-		MenuInnerPad:   menuInnerPad,
-		FooterLines:    2,
-		IsMinimum:      false,
-	}
-}
-
-func clamp(v, lo, hi int) int {
-	if v < lo {
-		return lo
-	}
-	if v > hi {
-		return hi
-	}
-	return v
-}
diff --git a/internal/ui/layout/responsive_test.go b/internal/ui/layout/responsive_test.go
deleted file mode 100644
index f80b188..0000000
--- a/internal/ui/layout/responsive_test.go
+++ /dev/null
@@ -1,73 +0,0 @@
-package layout_test
-
-import (
-	"testing"
-
-	"github.com/nebara/nebara-os/internal/ui/layout"
-)
-
-func TestCalculate_Normal(t *testing.T) {
-	c := layout.Calculate(120, 40)
-	if c.IsMinimum {
-		t.Error("120×40 should not be minimum")
-	}
-	if c.ContentWidth <= 0 {
-		t.Error("ContentWidth should be positive")
-	}
-	if c.MarginH <= 0 {
-		t.Error("MarginH should be positive")
-	}
-	if c.ContentWidth != c.TermWidth-c.MarginH*2 {
-		t.Errorf("ContentWidth mismatch: got %d, expected %d", c.ContentWidth, c.TermWidth-c.MarginH*2)
-	}
-}
-
-func TestCalculate_TooSmall(t *testing.T) {
-	c := layout.Calculate(40, 10)
-	if !c.IsMinimum {
-		t.Error("40×10 should be flagged as minimum/too-small")
-	}
-}
-
-func TestCalculate_BoundaryMinWidth(t *testing.T) {
-	c := layout.Calculate(layout.MinWidth, layout.MinHeight)
-	if c.IsMinimum {
-		t.Errorf("exact minimum %dx%d should not be flagged as too small", layout.MinWidth, layout.MinHeight)
-	}
-}
-
-func TestCalculate_MarginClamps(t *testing.T) {
-	// Very wide terminal: margin should not exceed 12.
-	cWide := layout.Calculate(400, 80)
-	if cWide.MarginH > 12 {
-		t.Errorf("MarginH should not exceed 12 on very wide terminal, got %d", cWide.MarginH)
-	}
-
-	// Narrow but valid terminal: margin should not go below 4.
-	cNarrow := layout.Calculate(60, 20)
-	if cNarrow.MarginH < 4 {
-		t.Errorf("MarginH should be at least 4 on narrow terminal, got %d", cNarrow.MarginH)
-	}
-}
-
-func TestCalculate_MessageVisibility(t *testing.T) {
-	cCompact := layout.Calculate(80, 23)
-	if cCompact.MessageVisible {
-		t.Error("message should be hidden on terminals shorter than 24 rows")
-	}
-	cNormal := layout.Calculate(80, 24)
-	if !cNormal.MessageVisible {
-		t.Error("message should be visible at 24 rows")
-	}
-}
-
-func TestCalculate_MenuInnerPad(t *testing.T) {
-	cNarrow := layout.Calculate(80, 24)
-	if cNarrow.MenuInnerPad != 1 {
-		t.Errorf("expected menu inner pad 1 for narrow terminal, got %d", cNarrow.MenuInnerPad)
-	}
-	cWide := layout.Calculate(120, 40)
-	if cWide.MenuInnerPad != 2 {
-		t.Errorf("expected menu inner pad 2 for wide terminal, got %d", cWide.MenuInnerPad)
-	}
-}
diff --git a/internal/ui/navigation/navigator.go b/internal/ui/navigation/navigator.go
deleted file mode 100644
index 9f1ae41..0000000
--- a/internal/ui/navigation/navigator.go
+++ /dev/null
@@ -1,127 +0,0 @@
-// Package navigation implements the menu navigation stack for Nebara OS TUI.
-package navigation
-
-import "github.com/nebara/nebara-os/internal/model"
-
-// Level represents one level in the navigation stack.
-type Level struct {
-	Items       []model.MenuItem
-	SelectedIdx int
-}
-
-// Navigator maintains a stack of menu levels and tracks the current position.
-type Navigator struct {
-	stack []Level
-}
-
-// NewNavigator creates a Navigator rooted at the main menu.
-func NewNavigator(items []model.MenuItem, initialIdx int) *Navigator {
-	if initialIdx < 0 || initialIdx >= len(items) {
-		initialIdx = 0
-	}
-	return &Navigator{
-		stack: []Level{
-			{Items: items, SelectedIdx: initialIdx},
-		},
-	}
-}
-
-// Current returns the active menu level.
-func (n *Navigator) Current() *Level {
-	if len(n.stack) == 0 {
-		return nil
-	}
-	return &n.stack[len(n.stack)-1]
-}
-
-// Depth returns the current nesting depth (0 = main menu).
-func (n *Navigator) Depth() int {
-	return len(n.stack) - 1
-}
-
-// IsAtRoot reports whether the navigator is at the main menu level.
-func (n *Navigator) IsAtRoot() bool {
-	return len(n.stack) == 1
-}
-
-// SelectedItem returns the currently highlighted menu item.
-func (n *Navigator) SelectedItem() *model.MenuItem {
-	cur := n.Current()
-	if cur == nil {
-		return nil
-	}
-	return &cur.Items[cur.SelectedIdx]
-}
-
-// MoveUp moves the selection one row up, clamping at the first item.
-func (n *Navigator) MoveUp() {
-	cur := n.Current()
-	if cur == nil {
-		return
-	}
-	if cur.SelectedIdx > 0 {
-		cur.SelectedIdx--
-	}
-}
-
-// MoveDown moves the selection one row down, clamping at the last item.
-func (n *Navigator) MoveDown() {
-	cur := n.Current()
-	if cur == nil {
-		return
-	}
-	if cur.SelectedIdx < len(cur.Items)-1 {
-		cur.SelectedIdx++
-	}
-}
-
-// MoveFirst jumps to the first item.
-func (n *Navigator) MoveFirst() {
-	cur := n.Current()
-	if cur != nil {
-		cur.SelectedIdx = 0
-	}
-}
-
-// MoveLast jumps to the last item.
-func (n *Navigator) MoveLast() {
-	cur := n.Current()
-	if cur != nil {
-		cur.SelectedIdx = len(cur.Items) - 1
-	}
-}
-
-// Enter descends into the submenu of the currently selected item.
-// Returns false when the item has no children (leaf node).
-func (n *Navigator) Enter() bool {
-	item := n.SelectedItem()
-	if item == nil || len(item.Children) == 0 {
-		return false
-	}
-	n.stack = append(n.stack, Level{
-		Items:       item.Children,
-		SelectedIdx: 0,
-	})
-	return true
-}
-
-// Back pops the current level from the stack, returning to the parent.
-// Returns false when already at the root.
-func (n *Navigator) Back() bool {
-	if len(n.stack) <= 1 {
-		return false
-	}
-	n.stack = n.stack[:len(n.stack)-1]
-	return true
-}
-
-// BreadcrumbTitle builds a display title for the current navigation depth.
-// It returns empty string when at the root.
-func (n *Navigator) BreadcrumbTitle() string {
-	if len(n.stack) <= 1 {
-		return ""
-	}
-	// Return the label of the parent item whose children we are browsing.
-	parent := n.stack[len(n.stack)-2]
-	return parent.Items[parent.SelectedIdx].Label
-}
diff --git a/internal/ui/navigation/navigator_test.go b/internal/ui/navigation/navigator_test.go
deleted file mode 100644
index ff8fe54..0000000
--- a/internal/ui/navigation/navigator_test.go
+++ /dev/null
@@ -1,170 +0,0 @@
-package navigation_test
-
-import (
-	"testing"
-
-	"github.com/nebara/nebara-os/internal/model"
-	"github.com/nebara/nebara-os/internal/ui/navigation"
-)
-
-func sampleItems() []model.MenuItem {
-	return []model.MenuItem{
-		{Label: "Item A", Description: "Desc A", Children: []model.MenuItem{
-			{Label: "Child A1", Description: "Desc A1"},
-			{Label: "Child A2", Description: "Desc A2"},
-		}},
-		{Label: "Item B", Description: "Desc B"},
-		{Label: "Item C", Description: "Desc C"},
-	}
-}
-
-func TestNewNavigator_InitialIndex(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 1)
-	if nav.Current().SelectedIdx != 1 {
-		t.Errorf("expected initial index 1, got %d", nav.Current().SelectedIdx)
-	}
-}
-
-func TestNewNavigator_InvalidIndex(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 99)
-	if nav.Current().SelectedIdx != 0 {
-		t.Errorf("out-of-range index should clamp to 0, got %d", nav.Current().SelectedIdx)
-	}
-}
-
-func TestMoveDown(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0)
-	nav.MoveDown()
-	if nav.Current().SelectedIdx != 1 {
-		t.Errorf("expected index 1 after MoveDown, got %d", nav.Current().SelectedIdx)
-	}
-}
-
-func TestMoveDown_Clamps(t *testing.T) {
-	items := sampleItems()
-	nav := navigation.NewNavigator(items, len(items)-1)
-	nav.MoveDown()
-	if nav.Current().SelectedIdx != len(items)-1 {
-		t.Errorf("MoveDown should clamp at last item")
-	}
-}
-
-func TestMoveUp(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 2)
-	nav.MoveUp()
-	if nav.Current().SelectedIdx != 1 {
-		t.Errorf("expected index 1 after MoveUp, got %d", nav.Current().SelectedIdx)
-	}
-}
-
-func TestMoveUp_Clamps(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0)
-	nav.MoveUp()
-	if nav.Current().SelectedIdx != 0 {
-		t.Errorf("MoveUp should clamp at 0")
-	}
-}
-
-func TestMoveFirst(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 2)
-	nav.MoveFirst()
-	if nav.Current().SelectedIdx != 0 {
-		t.Errorf("MoveFirst should jump to 0")
-	}
-}
-
-func TestMoveLast(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0)
-	nav.MoveLast()
-	last := len(sampleItems()) - 1
-	if nav.Current().SelectedIdx != last {
-		t.Errorf("MoveLast should jump to %d, got %d", last, nav.Current().SelectedIdx)
-	}
-}
-
-func TestEnter_HasChildren(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0) // Item A has children
-	ok := nav.Enter()
-	if !ok {
-		t.Fatal("Enter on item with children should return true")
-	}
-	if nav.Depth() != 1 {
-		t.Errorf("expected depth 1, got %d", nav.Depth())
-	}
-	if nav.Current().Items[0].Label != "Child A1" {
-		t.Errorf("expected Child A1, got %s", nav.Current().Items[0].Label)
-	}
-}
-
-func TestEnter_NoChildren(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 1) // Item B has no children
-	ok := nav.Enter()
-	if ok {
-		t.Fatal("Enter on leaf item should return false")
-	}
-	if nav.Depth() != 0 {
-		t.Errorf("depth should remain 0 for leaf enter")
-	}
-}
-
-func TestBack(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0)
-	nav.Enter()
-	ok := nav.Back()
-	if !ok {
-		t.Fatal("Back from submenu should return true")
-	}
-	if nav.Depth() != 0 {
-		t.Errorf("expected depth 0 after back, got %d", nav.Depth())
-	}
-}
-
-func TestBack_AtRoot(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0)
-	ok := nav.Back()
-	if ok {
-		t.Fatal("Back at root should return false")
-	}
-}
-
-func TestIsAtRoot(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0)
-	if !nav.IsAtRoot() {
-		t.Error("should be at root initially")
-	}
-	nav.Enter()
-	if nav.IsAtRoot() {
-		t.Error("should not be at root after Enter")
-	}
-	nav.Back()
-	if !nav.IsAtRoot() {
-		t.Error("should be at root after Back")
-	}
-}
-
-func TestSelectionPreservedAfterBack(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0)
-	nav.MoveDown() // idx=1
-	nav.MoveDown() // idx=2
-	nav.Back()     // at root, nothing changes
-	if nav.Current().SelectedIdx != 2 {
-		t.Errorf("selection should be 2, got %d", nav.Current().SelectedIdx)
-	}
-	nav.MoveFirst() // idx=0
-	nav.Enter()     // into Item A's children
-	nav.Back()      // back to root, parent should restore idx=0
-	if nav.Current().SelectedIdx != 0 {
-		t.Errorf("after returning from submenu, root selection should be 0, got %d", nav.Current().SelectedIdx)
-	}
-}
-
-func TestBreadcrumbTitle(t *testing.T) {
-	nav := navigation.NewNavigator(sampleItems(), 0)
-	if nav.BreadcrumbTitle() != "" {
-		t.Error("breadcrumb should be empty at root")
-	}
-	nav.Enter()
-	if nav.BreadcrumbTitle() != "Item A" {
-		t.Errorf("breadcrumb should be 'Item A', got %q", nav.BreadcrumbTitle())
-	}
-}
diff --git a/internal/ui/theme/colors.go b/internal/ui/theme/colors.go
deleted file mode 100644
index 924b645..0000000
--- a/internal/ui/theme/colors.go
+++ /dev/null
@@ -1,70 +0,0 @@
-// Package theme defines centralized color constants and text styles
-// for the Nebara OS TUI design system.
-package theme
-
-import "github.com/gdamore/tcell/v2"
-
-// Color design tokens — do not modify these values.
-// They are final design specifications from the Nebara OS design system.
-const (
-	HexBackground  = "#000000"
-	HexPrimary     = "#F5F5F5"
-	HexSecondary   = "#BBBBBB"
-	HexBorder      = "#BBBBBB"
-	HexSelectionBg = "#BBBBBB"
-	HexSelectionFg = "#000000"
-	HexWarning     = "#FFCC00"
-	HexError       = "#B30D18"
-	HexInfo        = "#0088FF"
-	HexLogoAccent  = "#B30D18"
-)
-
-// Resolved tcell colors from the design token hex values.
-var (
-	ColorBackground  = tcell.NewHexColor(0x000000)
-	ColorPrimary     = tcell.NewHexColor(0xF5F5F5)
-	ColorSecondary   = tcell.NewHexColor(0xBBBBBB)
-	ColorBorder      = tcell.NewHexColor(0xBBBBBB)
-	ColorSelectionBg = tcell.NewHexColor(0xBBBBBB)
-	ColorSelectionFg = tcell.NewHexColor(0x000000)
-	ColorWarning     = tcell.NewHexColor(0xFFCC00)
-	ColorError       = tcell.NewHexColor(0xB30D18)
-	ColorInfo        = tcell.NewHexColor(0x0088FF)
-	ColorLogoAccent  = tcell.NewHexColor(0xB30D18)
-)
-
-// StyleNormal is the default text style: primary foreground on black.
-var StyleNormal = tcell.StyleDefault.
-	Background(ColorBackground).
-	Foreground(ColorPrimary)
-
-// StyleSecondary is used for labels and secondary information.
-var StyleSecondary = tcell.StyleDefault.
-	Background(ColorBackground).
-	Foreground(ColorSecondary)
-
-// StyleBold is used for product title and header text.
-var StyleBold = tcell.StyleDefault.
-	Background(ColorBackground).
-	Foreground(ColorPrimary).
-	Bold(true)
-
-// StyleSelected is the highlighted menu row style.
-var StyleSelected = tcell.StyleDefault.
-	Background(ColorSelectionBg).
-	Foreground(ColorSelectionFg)
-
-// StyleWarning applies the warning foreground color.
-var StyleWarning = tcell.StyleDefault.
-	Background(ColorBackground).
-	Foreground(ColorWarning)
-
-// StyleError applies the error foreground color.
-var StyleError = tcell.StyleDefault.
-	Background(ColorBackground).
-	Foreground(ColorError)
-
-// StyleInfo applies the info foreground color.
-var StyleInfo = tcell.StyleDefault.
-	Background(ColorBackground).
-	Foreground(ColorInfo)