feat(ui): 主题切换 + 语言持久化 + About 对话框

- 新增 light/dark 主题调色板与 Windows 注册表系统主题探测
- 偏好设置对话框：主题三选一 + 语言下拉(en/zh-CN/de)，即时生效
- 持久化 Language/Theme/AutoLockMinutes/MinimizeToTray 至 YAML 顶层
- 启动时按 config 中保存的语言初始化 i18n
- About 对话框展示 version/runtime/项目地址/许可证
- 全部硬编码颜色迁移到 themePalette，为深色模式做准备

cmd/winauth/main.go

@@ -6,10 +6,12 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"git.wxccs.org/iceking2nd/winauth-go/internal/config"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/global"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/i18n"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/logging"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/ui"
+	"git.wxccs.org/iceking2nd/winauth-go/internal/version"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/win32"
 )
 
@@ -53,7 +55,8 @@ func main() {
 			}
 
 			const fn = "cmd.winauth.main"
-			global.Log.WithField("func", fn).Info("winauth-go starting")
+			global.Log.WithField("func", fn).
+				WithField("version", version.String()).Info("winauth-go starting")
 
 			release, alreadyRunning, err := win32.AcquireInstanceLock(singleInstanceMutex)
 			if err != nil {
@@ -70,7 +73,12 @@ func main() {
 				defer release()
 			}
 
-			if err := i18n.Init(""); err != nil {
+			// Peek the config (without password) to recover the user's
+			// last language choice before initialising i18n. Encrypted
+			// configs still expose Language at the YAML top level so we
+			// can localise the password prompt itself.
+			lang := preferredLanguage(configPath)
+			if err := i18n.Init(lang); err != nil {
 				global.Log.WithField("func", fn).WithError(err).Warn("i18n init failed; falling back to keys")
 			}
 
@@ -91,3 +99,19 @@ func main() {
 		os.Exit(1)
 	}
 }
+
+// preferredLanguage reads the user's saved language tag out of the YAML
+// config without requiring a passphrase. We resolve the default config
+// path when configPath is blank and silently return "" on any failure;
+// callers fall back to the i18n default in that case. Encrypted configs
+// still expose the top-level Language field so this works for them too.
+func preferredLanguage(configPath string) string {
+	if configPath == "" {
+		configPath = config.DefaultPath()
+	}
+	cfg, _ := config.LoadYAML(configPath, nil)
+	if cfg == nil {
+		return ""
+	}
+	return cfg.Language
+}

internal/config/model.go

@@ -21,9 +21,17 @@ type Entry struct {
 // default; if Encrypted is true, EncryptedBlob holds a WAGO1 base64 ciphertext
 // produced by internal/crypto.EncryptModern and Entries is empty on disk.
 type Config struct {
-	Version       int     `yaml:"version" json:"version"`
-	Language      string  `yaml:"language,omitempty" json:"language,omitempty"`
-	Encrypted     bool    `yaml:"encrypted" json:"encrypted"`
-	EncryptedBlob string  `yaml:"encrypted_blob,omitempty" json:"encrypted_blob,omitempty"`
-	Entries       []Entry `yaml:"entries,omitempty" json:"entries,omitempty"`
+	Version  int    `yaml:"version" json:"version"`
+	Language string `yaml:"language,omitempty" json:"language,omitempty"`
+	// Theme is one of "", "light", "dark", "system" (empty = system).
+	Theme string `yaml:"theme,omitempty" json:"theme,omitempty"`
+	// AutoLockMinutes locks the UI (hides codes, requires password) after
+	// this many minutes of inactivity. 0 disables auto-lock.
+	AutoLockMinutes int `yaml:"auto_lock_minutes,omitempty" json:"auto_lock_minutes,omitempty"`
+	// MinimizeToTray sends the window to the system tray instead of
+	// exiting when the close button is pressed.
+	MinimizeToTray bool    `yaml:"minimize_to_tray,omitempty" json:"minimize_to_tray,omitempty"`
+	Encrypted      bool    `yaml:"encrypted" json:"encrypted"`
+	EncryptedBlob  string  `yaml:"encrypted_blob,omitempty" json:"encrypted_blob,omitempty"`
+	Entries        []Entry `yaml:"entries,omitempty" json:"entries,omitempty"`
 }

internal/i18n/locales/de.toml

@@ -367,3 +367,55 @@ other = "QR-Scan fehlgeschlagen: %s"
 
 [msg_clipboard_no_image]
 other = "Zwischenablage enthält kein Bild"
+
+# --- Einstellungen ---
+
+[menu_preferences]
+other = "Einstellungen..."
+
+[dialog_preferences_title]
+other = "Einstellungen"
+
+[label_theme]
+other = "Design"
+
+[theme_system]
+other = "System"
+
+[theme_light]
+other = "Hell"
+
+[theme_dark]
+other = "Dunkel"
+
+[label_language]
+other = "Sprache"
+
+# --- Über-Dialog ---
+
+[dialog_about_title]
+other = "Über WinAuth"
+
+[about_app_name]
+other = "WinAuth (Go-Portierung) — TOTP/HOTP-Authentifikator"
+
+[about_version_label]
+other = "Version"
+
+[about_runtime_label]
+other = "Laufzeit"
+
+[about_project_label]
+other = "Projekt"
+
+[about_project_url]
+other = "https://git.wxccs.org/iceking2nd/winauth-go"
+
+[about_license_label]
+other = "Lizenz"
+
+[about_license_value]
+other = "MIT"
+
+[about_credits]
+other = "Original-WinAuth von Colin Mackie. Go-Portierung wird von den Projektautoren gepflegt."

internal/i18n/locales/en.toml

@@ -369,3 +369,55 @@ other = "QR scan failed: %s"
 
 [msg_clipboard_no_image]
 other = "Clipboard does not contain an image"
+
+# --- Preferences ---
+
+[menu_preferences]
+other = "Preferences..."
+
+[dialog_preferences_title]
+other = "Preferences"
+
+[label_theme]
+other = "Theme"
+
+[theme_system]
+other = "System"
+
+[theme_light]
+other = "Light"
+
+[theme_dark]
+other = "Dark"
+
+[label_language]
+other = "Language"
+
+# --- About dialog ---
+
+[dialog_about_title]
+other = "About WinAuth"
+
+[about_app_name]
+other = "WinAuth (Go port) — TOTP/HOTP authenticator"
+
+[about_version_label]
+other = "Version"
+
+[about_runtime_label]
+other = "Runtime"
+
+[about_project_label]
+other = "Project"
+
+[about_project_url]
+other = "https://git.wxccs.org/iceking2nd/winauth-go"
+
+[about_license_label]
+other = "License"
+
+[about_license_value]
+other = "MIT"
+
+[about_credits]
+other = "Original WinAuth by Colin Mackie. Go port maintained by the project authors."

internal/i18n/locales/zh-CN.toml

@@ -367,3 +367,55 @@ other = "二维码扫描失败：%s"
 
 [msg_clipboard_no_image]
 other = "剪贴板中没有图片"
+
+# --- 偏好设置 ---
+
+[menu_preferences]
+other = "偏好设置..."
+
+[dialog_preferences_title]
+other = "偏好设置"
+
+[label_theme]
+other = "主题"
+
+[theme_system]
+other = "跟随系统"
+
+[theme_light]
+other = "浅色"
+
+[theme_dark]
+other = "深色"
+
+[label_language]
+other = "语言"
+
+# --- 关于对话框 ---
+
+[dialog_about_title]
+other = "关于 WinAuth"
+
+[about_app_name]
+other = "WinAuth (Go 版) — TOTP/HOTP 验证器"
+
+[about_version_label]
+other = "版本"
+
+[about_runtime_label]
+other = "运行时"
+
+[about_project_label]
+other = "项目主页"
+
+[about_project_url]
+other = "https://git.wxccs.org/iceking2nd/winauth-go"
+
+[about_license_label]
+other = "许可证"
+
+[about_license_value]
+other = "MIT"
+
+[about_credits]
+other = "原版 WinAuth 由 Colin Mackie 创作。Go 移植由本项目作者维护。"

internal/ui/app.go

@@ -10,12 +10,10 @@ import (
 	"time"
 
 	"gioui.org/app"
-	"gioui.org/font/gofont"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/clip"
 	"gioui.org/op/paint"
-	"gioui.org/text"
 	"gioui.org/unit"
 	"gioui.org/widget"
 	"gioui.org/widget/material"
@@ -95,6 +93,8 @@ type appState struct {
 	hotkeyDialog *hotkeyDialog
 	hotkeyTarget *entry
 	tradesDialog *steamTradesDialog
+	prefsDialog  *preferencesDialog
+	aboutDialog  *aboutDialog
 
 	store   *store
 	saveErr string // surfaced in the top bar
@@ -102,6 +102,13 @@ type appState struct {
 	hkMgr *win32.HotkeyManager
 
 	toast toast
+
+	// themeMode is the user's current theme preference. drawFrame
+	// rebuilds the material.Theme when this changes.
+	themeMode themeMode
+	// theme is the cached material.Theme matching themeMode. nil forces a
+	// rebuild on the next frame.
+	theme *material.Theme
 }
 
 // snapshotEntries returns a freshly serialized slice of config entries.
@@ -119,9 +126,6 @@ func (st *appState) snapshotEntries() []config.Entry {
 func loop(w *app.Window, configPath string) error {
 	const fn = "internal.ui.loop"
 
-	th := material.NewTheme()
-	th.Shaper = text.NewShaper(text.WithCollection(gofont.Collection()))
-
 	state := &appState{}
 	state.list.Axis = layout.Vertical
 
@@ -146,6 +150,12 @@ func loop(w *app.Window, configPath string) error {
 		state.absorbConfig(cfg)
 	}
 
+	// Seed the theme cache from the stored preference. Empty / unknown
+	// values resolve to "system" which buildTheme then maps to light or
+	// dark via the OS-specific systemPrefersDark probe.
+	_, themePref, _, _ := state.store.Preferences()
+	state.themeMode = normalizeThemeMode(themePref)
+
 	// Spin up the global hotkey manager and register whatever the user
 	// already had configured. Failures are non-fatal (logged + the row
 	// just won't fire).
@@ -170,7 +180,15 @@ func loop(w *app.Window, configPath string) error {
 			return e.Err
 		case app.FrameEvent:
 			gtx := app.NewContext(&ops, e)
-			drawFrame(gtx, th, state, w)
+			if state.theme == nil {
+				th, pal := buildTheme(state.themeMode)
+				state.theme = th
+				activePalette = pal
+			}
+			// Paint the window background using the active palette so
+			// dark mode does not show through as the Gio default grey.
+			fillBackground(gtx, activePalette.Background)
+			drawFrame(gtx, state.theme, state, w)
 			e.Frame(gtx.Ops)
 		}
 	}
@@ -320,8 +338,11 @@ func drawFrame(gtx layout.Context, th *material.Theme, st *appState, w *app.Wind
 				st.setPwDialog = newSetPasswordDialog()
 			case settingsActionImportLegacy:
 				st.importDialog = newImportLegacyDialog()
+			case settingsActionPreferences:
+				lang, theme, _, _ := st.store.Preferences()
+				st.prefsDialog = newPreferencesDialog(lang, normalizeThemeMode(theme))
 			case settingsActionAbout:
-				// TODO: about dialog (next phase).
+				st.aboutDialog = newAboutDialog()
 			}
 			w.Invalidate()
 		} else {
@@ -329,6 +350,27 @@ func drawFrame(gtx layout.Context, th *material.Theme, st *appState, w *app.Wind
 		}
 	}
 
+	if st.prefsDialog != nil {
+		return st.prefsDialog.Layout(gtx, th, func(r preferencesResult) {
+			if !r.cancel {
+				_, _, autoLock, minToTray := st.store.Preferences()
+				st.store.SetPreferences(r.language, string(r.theme), autoLock, minToTray)
+				i18n.SetLanguage(r.language)
+				st.themeMode = r.theme
+				st.theme = nil // force rebuild on next frame
+			}
+			st.prefsDialog = nil
+			w.Invalidate()
+		})
+	}
+
+	if st.aboutDialog != nil {
+		return st.aboutDialog.Layout(gtx, th, func() {
+			st.aboutDialog = nil
+			w.Invalidate()
+		})
+	}
+
 	if st.importDialog != nil {
 		return st.importDialog.Layout(gtx, th, func(r importLegacyResult) {
 			if !r.cancel && r.cfg != nil {
@@ -427,7 +469,7 @@ func drawFrame(gtx layout.Context, th *material.Theme, st *appState, w *app.Wind
 					return layout.Dimensions{}
 				}
 				lbl := material.Body2(th, msg)
-				lbl.Color = color.NRGBA{R: 0xc0, A: 0xff}
+				lbl.Color = activePalette.ErrorFg
 				return layout.Inset{Top: unit.Dp(4)}.Layout(gtx, lbl.Layout)
 			}),
 			layout.Rigid(layout.Spacer{Height: unit.Dp(8)}.Layout),
@@ -487,7 +529,7 @@ func entryRow(gtx layout.Context, th *material.Theme, en *entry) layout.Dimensio
 						}),
 						layout.Rigid(func(gtx layout.Context) layout.Dimensions {
 							lbl := material.H6(th, en.Code)
-							lbl.Color = color.NRGBA{R: 0x10, G: 0x70, B: 0xff, A: 0xff}
+							lbl.Color = activePalette.RingFg
 							return lbl.Layout(gtx)
 						}),
 					)

internal/ui/dialog.go

@@ -1,8 +1,6 @@
 package ui
 
 import (
-	"image/color"
-
 	"gioui.org/layout"
 	"gioui.org/unit"
 	"gioui.org/widget"
@@ -36,16 +34,16 @@ func modalCard(
 	cancelBtn *widget.Clickable,
 	body layout.Widget,
 ) layout.Dimensions {
-	fillBackground(gtx, color.NRGBA{R: 0, G: 0, B: 0, A: 0x60})
+	fillBackground(gtx, activePalette.ScrimBg)
 
 	return layout.Center.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 		gtx.Constraints.Max.X = gtx.Dp(420)
 		return widget.Border{
-			Color:        color.NRGBA{R: 0x55, G: 0x55, B: 0x55, A: 0xff},
+			Color:        activePalette.DialogBorder,
 			CornerRadius: unit.Dp(4),
 			Width:        unit.Dp(1),
 		}.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
-			fillBackground(gtx, color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff})
+			fillBackground(gtx, activePalette.DialogBg)
 			return layout.UniformInset(unit.Dp(16)).Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 				return layout.Flex{Axis: layout.Vertical}.Layout(gtx,
 					layout.Rigid(material.H6(th, title).Layout),
@@ -79,16 +77,16 @@ func modalCardCancel(
 	cancelBtn *widget.Clickable,
 	body layout.Widget,
 ) layout.Dimensions {
-	fillBackground(gtx, color.NRGBA{R: 0, G: 0, B: 0, A: 0x60})
+	fillBackground(gtx, activePalette.ScrimBg)
 
 	return layout.Center.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 		gtx.Constraints.Max.X = gtx.Dp(420)
 		return widget.Border{
-			Color:        color.NRGBA{R: 0x55, G: 0x55, B: 0x55, A: 0xff},
+			Color:        activePalette.DialogBorder,
 			CornerRadius: unit.Dp(4),
 			Width:        unit.Dp(1),
 		}.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
-			fillBackground(gtx, color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff})
+			fillBackground(gtx, activePalette.DialogBg)
 			return layout.UniformInset(unit.Dp(16)).Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 				return layout.Flex{Axis: layout.Vertical}.Layout(gtx,
 					layout.Rigid(material.H6(th, title).Layout),
@@ -114,7 +112,7 @@ func errorLabel(th *material.Theme, msg string) layout.Widget {
 			return layout.Dimensions{}
 		}
 		lbl := material.Body2(th, msg)
-		lbl.Color = color.NRGBA{R: 0xc0, A: 0xff}
+		lbl.Color = activePalette.ErrorFg
 		return layout.Inset{Top: unit.Dp(8)}.Layout(gtx, lbl.Layout)
 	}
 }

internal/ui/dialog_about.go

@@ -0,0 +1,55 @@
+package ui
+
+import (
+	"runtime"
+
+	"gioui.org/layout"
+	"gioui.org/unit"
+	"gioui.org/widget"
+	"gioui.org/widget/material"
+
+	"git.wxccs.org/iceking2nd/winauth-go/internal/i18n"
+	"git.wxccs.org/iceking2nd/winauth-go/internal/version"
+)
+
+// aboutDialog is a read-only popup describing the build, runtime and a
+// short credits / project link blurb. Click "Close" to dismiss.
+type aboutDialog struct {
+	closeBt widget.Clickable
+}
+
+func newAboutDialog() *aboutDialog { return &aboutDialog{} }
+
+// Layout follows the simpler "single button" contract: onDone is called
+// with no arguments when the user dismisses the dialog.
+func (d *aboutDialog) Layout(
+	gtx layout.Context, th *material.Theme,
+	onDone func(),
+) layout.Dimensions {
+	if d.closeBt.Clicked(gtx) {
+		onDone()
+		return layout.Dimensions{Size: gtx.Constraints.Max}
+	}
+
+	body := func(gtx layout.Context) layout.Dimensions {
+		line := func(text string) layout.FlexChild {
+			return layout.Rigid(func(gtx layout.Context) layout.Dimensions {
+				return layout.Inset{Top: unit.Dp(2), Bottom: unit.Dp(2)}.Layout(gtx,
+					material.Body2(th, text).Layout)
+			})
+		}
+		return layout.Flex{Axis: layout.Vertical}.Layout(gtx,
+			line(i18n.T("about_app_name")),
+			line(i18n.T("about_version_label")+": "+version.String()),
+			line(i18n.T("about_runtime_label")+": "+runtime.Version()+" ("+runtime.GOOS+"/"+runtime.GOARCH+")"),
+			layout.Rigid(layout.Spacer{Height: unit.Dp(8)}.Layout),
+			line(i18n.T("about_project_label")+": "+i18n.T("about_project_url")),
+			line(i18n.T("about_license_label")+": "+i18n.T("about_license_value")),
+			layout.Rigid(layout.Spacer{Height: unit.Dp(8)}.Layout),
+			line(i18n.T("about_credits")),
+		)
+	}
+
+	return modalCardCancel(gtx, th, i18n.T("dialog_about_title"),
+		i18n.T("btn_close"), &d.closeBt, body)
+}

internal/ui/dialog_preferences.go

@@ -0,0 +1,136 @@
+package ui
+
+import (
+	"gioui.org/layout"
+	"gioui.org/unit"
+	"gioui.org/widget"
+	"gioui.org/widget/material"
+
+	"git.wxccs.org/iceking2nd/winauth-go/internal/i18n"
+)
+
+// preferencesDialog edits the persistent UI prefs: UI language and
+// theme. Auto-lock and minimize-to-tray live in their own bucket and
+// will appear here later.
+type preferencesDialog struct {
+	lang  string
+	theme themeMode
+
+	// Theme selection — three "radio" buttons.
+	themeSystemBt widget.Clickable
+	themeLightBt  widget.Clickable
+	themeDarkBt   widget.Clickable
+
+	// Language selection — one button per supported locale. Cheap
+	// substitute for a dropdown until Gio gains a native one.
+	langEnBt   widget.Clickable
+	langZhCNBt widget.Clickable
+	langDeBt   widget.Clickable
+
+	okBt     widget.Clickable
+	cancelBt widget.Clickable
+}
+
+// preferencesResult is what Layout's callback receives. cancel skips
+// any persistence.
+type preferencesResult struct {
+	cancel   bool
+	language string
+	theme    themeMode
+}
+
+// supportedLanguages is the closed set the prefs dialog exposes. Keep
+// in sync with internal/i18n/locales/*.toml.
+var supportedLanguages = []struct {
+	tag   string
+	label string
+}{
+	{"en", "English"},
+	{"zh-CN", "中文 (简体)"},
+	{"de", "Deutsch"},
+}
+
+func newPreferencesDialog(currentLang string, currentTheme themeMode) *preferencesDialog {
+	if currentLang == "" {
+		currentLang = "en"
+	}
+	if currentTheme == "" {
+		currentTheme = themeSystem
+	}
+	return &preferencesDialog{lang: currentLang, theme: currentTheme}
+}
+
+func (d *preferencesDialog) Layout(
+	gtx layout.Context, th *material.Theme,
+	onDone func(preferencesResult),
+) layout.Dimensions {
+	if d.cancelBt.Clicked(gtx) {
+		onDone(preferencesResult{cancel: true})
+		return layout.Dimensions{Size: gtx.Constraints.Max}
+	}
+	if d.okBt.Clicked(gtx) {
+		onDone(preferencesResult{language: d.lang, theme: d.theme})
+		return layout.Dimensions{Size: gtx.Constraints.Max}
+	}
+
+	// Map button clicks to model updates before the next layout.
+	switch {
+	case d.themeSystemBt.Clicked(gtx):
+		d.theme = themeSystem
+	case d.themeLightBt.Clicked(gtx):
+		d.theme = themeLight
+	case d.themeDarkBt.Clicked(gtx):
+		d.theme = themeDark
+	case d.langEnBt.Clicked(gtx):
+		d.lang = "en"
+	case d.langZhCNBt.Clicked(gtx):
+		d.lang = "zh-CN"
+	case d.langDeBt.Clicked(gtx):
+		d.lang = "de"
+	}
+
+	// Render one labeled "chip" — emphasised when selected, regular
+	// otherwise. Implemented as a material.Button so the click target
+	// stays generous without us hand-rolling a Pointer area.
+	chip := func(btn *widget.Clickable, label string, selected bool) layout.FlexChild {
+		return layout.Rigid(func(gtx layout.Context) layout.Dimensions {
+			return layout.Inset{Right: unit.Dp(8), Bottom: unit.Dp(4)}.Layout(gtx,
+				func(gtx layout.Context) layout.Dimensions {
+					b := material.Button(th, btn, label)
+					if !selected {
+						b.Background = activePalette.RingBg
+						b.Color = activePalette.OnBackground
+					}
+					return b.Layout(gtx)
+				})
+		})
+	}
+
+	body := func(gtx layout.Context) layout.Dimensions {
+		return layout.Flex{Axis: layout.Vertical}.Layout(gtx,
+			layout.Rigid(material.Body1(th, i18n.T("label_theme")).Layout),
+			layout.Rigid(layout.Spacer{Height: unit.Dp(6)}.Layout),
+			layout.Rigid(func(gtx layout.Context) layout.Dimensions {
+				return layout.Flex{Axis: layout.Horizontal}.Layout(gtx,
+					chip(&d.themeSystemBt, i18n.T("theme_system"), d.theme == themeSystem),
+					chip(&d.themeLightBt, i18n.T("theme_light"), d.theme == themeLight),
+					chip(&d.themeDarkBt, i18n.T("theme_dark"), d.theme == themeDark),
+				)
+			}),
+			layout.Rigid(layout.Spacer{Height: unit.Dp(12)}.Layout),
+			layout.Rigid(material.Body1(th, i18n.T("label_language")).Layout),
+			layout.Rigid(layout.Spacer{Height: unit.Dp(6)}.Layout),
+			layout.Rigid(func(gtx layout.Context) layout.Dimensions {
+				return layout.Flex{Axis: layout.Horizontal}.Layout(gtx,
+					chip(&d.langEnBt, supportedLanguages[0].label, d.lang == "en"),
+					chip(&d.langZhCNBt, supportedLanguages[1].label, d.lang == "zh-CN"),
+					chip(&d.langDeBt, supportedLanguages[2].label, d.lang == "de"),
+				)
+			}),
+		)
+	}
+
+	return modalCard(gtx, th, i18n.T("dialog_preferences_title"),
+		i18n.T("btn_ok"), i18n.T("btn_cancel"),
+		&d.okBt, &d.cancelBt, body)
+}

internal/ui/entry_actions.go

@@ -2,7 +2,6 @@ package ui
 
 import (
 	"image"
-	"image/color"
 
 	"gioui.org/app"
 	"gioui.org/layout"
@@ -39,7 +38,7 @@ func (st *appState) copyCodeToClipboard(en *entry, w *app.Window) {
 func drawEmptyPlaceholder(gtx layout.Context, th *material.Theme) layout.Dimensions {
 	return layout.Center.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 		lbl := material.Body1(th, i18n.T("msg_empty_list"))
-		lbl.Color = color.NRGBA{R: 0x80, G: 0x80, B: 0x80, A: 0xff}
+		lbl.Color = activePalette.MutedFg
 		return layout.UniformInset(unit.Dp(8)).Layout(gtx, lbl.Layout)
 	})
 }
@@ -50,7 +49,7 @@ func drawDivider(gtx layout.Context) layout.Dimensions {
 	h := gtx.Dp(unit.Dp(1))
 	size := image.Pt(gtx.Constraints.Max.X, h)
 	defer clip.Rect{Max: size}.Push(gtx.Ops).Pop()
-	paint.ColorOp{Color: color.NRGBA{R: 0xe0, G: 0xe0, B: 0xe0, A: 0xff}}.Add(gtx.Ops)
+	paint.ColorOp{Color: activePalette.Divider}.Add(gtx.Ops)
 	paint.PaintOp{}.Add(gtx.Ops)
 	return layout.Dimensions{Size: size}
 }

internal/ui/entry_ring.go

@@ -1,7 +1,6 @@
 package ui
 
 import (
-	"image/color"
 	"time"
 
 	"gioui.org/layout"
@@ -28,11 +27,11 @@ func entryProgressRing(gtx layout.Context, en *entry) layout.Dimensions {
 	remaining := int64(period) - elapsed
 	progress := float32(remaining) / float32(period)
 
-	fg := color.NRGBA{R: 0x10, G: 0x70, B: 0xff, A: 0xff}
+	fg := activePalette.RingFg
 	if remaining <= 5 {
-		fg = color.NRGBA{R: 0xd0, G: 0x30, B: 0x30, A: 0xff}
+		fg = activePalette.RingFgWarn
 	}
-	bg := color.NRGBA{R: 0xd8, G: 0xd8, B: 0xd8, A: 0xff}
+	bg := activePalette.RingBg
 
 	return progressRing{
 		Size:     unit.Dp(ringDp),

internal/ui/settings_menu.go

@@ -1,8 +1,6 @@
 package ui
 
 import (
-	"image/color"
-
 	"gioui.org/layout"
 	"gioui.org/unit"
 	"gioui.org/widget"
@@ -18,6 +16,7 @@ const (
 	settingsActionNone settingsAction = iota
 	settingsActionSetPassword
 	settingsActionImportLegacy
+	settingsActionPreferences
 	settingsActionAbout
 )
 
@@ -26,6 +25,7 @@ const (
 type settingsMenu struct {
 	setPwBtn  widget.Clickable
 	importBtn widget.Clickable
+	prefsBtn  widget.Clickable
 	aboutBtn  widget.Clickable
 	cancelBtn widget.Clickable
 }
@@ -39,6 +39,8 @@ func (m *settingsMenu) Pick(gtx layout.Context) (settingsAction, bool) {
 		return settingsActionSetPassword, true
 	case m.importBtn.Clicked(gtx):
 		return settingsActionImportLegacy, true
+	case m.prefsBtn.Clicked(gtx):
+		return settingsActionPreferences, true
 	case m.aboutBtn.Clicked(gtx):
 		return settingsActionAbout, true
 	case m.cancelBtn.Clicked(gtx):
@@ -48,7 +50,7 @@ func (m *settingsMenu) Pick(gtx layout.Context) (settingsAction, bool) {
 }
 
 func (m *settingsMenu) Layout(gtx layout.Context, th *material.Theme) layout.Dimensions {
-	fillBackground(gtx, color.NRGBA{R: 0, G: 0, B: 0, A: 0x60})
+	fillBackground(gtx, activePalette.ScrimBg)
 
 	row := func(btn *widget.Clickable, label string) layout.FlexChild {
 		return layout.Rigid(func(gtx layout.Context) layout.Dimensions {
@@ -63,17 +65,18 @@ func (m *settingsMenu) Layout(gtx layout.Context, th *material.Theme) layout.Dim
 	return layout.Center.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 		gtx.Constraints.Max.X = gtx.Dp(280)
 		return widget.Border{
-			Color:        color.NRGBA{R: 0x55, G: 0x55, B: 0x55, A: 0xff},
+			Color:        activePalette.DialogBorder,
 			CornerRadius: unit.Dp(4),
 			Width:        unit.Dp(1),
 		}.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
-			fillBackground(gtx, color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff})
+			fillBackground(gtx, activePalette.DialogBg)
 			return layout.UniformInset(unit.Dp(16)).Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 				return layout.Flex{Axis: layout.Vertical}.Layout(gtx,
 					layout.Rigid(material.H6(th, i18n.T("menu_settings")).Layout),
 					layout.Rigid(layout.Spacer{Height: unit.Dp(12)}.Layout),
 					row(&m.setPwBtn, i18n.T("menu_set_password")),
 					row(&m.importBtn, i18n.T("menu_import_legacy")),
+					row(&m.prefsBtn, i18n.T("menu_preferences")),
 					row(&m.aboutBtn, i18n.T("menu_about")),
 					layout.Rigid(layout.Spacer{Height: unit.Dp(8)}.Layout),
 					layout.Rigid(func(gtx layout.Context) layout.Dimensions {

internal/ui/store.go

@@ -26,6 +26,13 @@ type store struct {
 	passphrase []byte
 	encrypted  bool
 
+	// Top-level user preferences kept alongside entries so save() can
+	// roundtrip them without requiring the UI to rebuild a full Config.
+	language        string
+	theme           string
+	autoLockMinutes int
+	minimizeToTray  bool
+
 	// dirty signals a save is pending. The worker reads & resets it.
 	dirty       bool
 	snapshotFn  func() []config.Entry
@@ -37,6 +44,27 @@ type store struct {
 	onError func(error)
 }
 
+// Preferences returns the persisted top-level prefs. UI code reads these
+// after Load to seed dialog defaults.
+func (s *store) Preferences() (language, theme string, autoLockMinutes int, minimizeToTray bool) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.language, s.theme, s.autoLockMinutes, s.minimizeToTray
+}
+
+// SetPreferences updates the persisted top-level prefs and schedules a
+// save. Callers pass the current value for each field — there is no
+// per-field "leave unchanged" sentinel.
+func (s *store) SetPreferences(language, theme string, autoLockMinutes int, minimizeToTray bool) {
+	s.mu.Lock()
+	s.language = language
+	s.theme = theme
+	s.autoLockMinutes = autoLockMinutes
+	s.minimizeToTray = minimizeToTray
+	s.mu.Unlock()
+	s.Push()
+}
+
 // newStore initializes a store and starts the background save worker.
 // snapshotFn is invoked whenever a save runs; it must return a freshly
 // copied entries slice (the worker holds no UI locks). onError is called
@@ -86,6 +114,10 @@ func (s *store) Load(passphrase []byte) (*config.Config, error) {
 	s.mu.Lock()
 	s.passphrase = passphrase
 	s.encrypted = cfg.Encrypted
+	s.language = cfg.Language
+	s.theme = cfg.Theme
+	s.autoLockMinutes = cfg.AutoLockMinutes
+	s.minimizeToTray = cfg.MinimizeToTray
 	s.mu.Unlock()
 	logger.WithField("entries", len(cfg.Entries)).Debug("config loaded into store")
 	return cfg, nil
@@ -148,13 +180,21 @@ func (s *store) run() {
 		s.dirty = false
 		pw := append([]byte(nil), s.passphrase...)
 		enc := s.encrypted
+		lang := s.language
+		theme := s.theme
+		autoLock := s.autoLockMinutes
+		minToTray := s.minimizeToTray
 		s.mu.Unlock()
 
 		entries := s.snapshotFn()
 		cfg := &config.Config{
-			Version:   1,
-			Encrypted: enc,
-			Entries:   entries,
+			Version:         1,
+			Language:        lang,
+			Theme:           theme,
+			AutoLockMinutes: autoLock,
+			MinimizeToTray:  minToTray,
+			Encrypted:       enc,
+			Entries:         entries,
 		}
 		if err := config.SaveYAML(cfg, s.path, pw); err != nil {
 			global.Log.WithField("func", fn).WithError(err).Error("save failed")

internal/ui/theme.go

@@ -0,0 +1,122 @@
+// Package ui internal helpers — theme palette + system-theme detection.
+
+package ui
+
+import (
+	"image/color"
+
+	"gioui.org/font/gofont"
+	"gioui.org/text"
+	"gioui.org/widget/material"
+)
+
+// themeMode is one of the user-selectable theme settings.
+type themeMode string
+
+const (
+	themeSystem themeMode = "system"
+	themeLight  themeMode = "light"
+	themeDark   themeMode = "dark"
+)
+
+// themePalette holds the small set of colors the app itself draws
+// (toast, dividers, ring background, etc). The material.Theme handles
+// button + body text colors via its own palette.
+type themePalette struct {
+	Background   color.NRGBA
+	OnBackground color.NRGBA
+	Divider      color.NRGBA
+	RingBg       color.NRGBA
+	RingFg       color.NRGBA
+	RingFgWarn   color.NRGBA
+	ToastBg      color.NRGBA
+	ToastFg      color.NRGBA
+	ErrorFg      color.NRGBA
+	DialogBg     color.NRGBA
+	DialogBorder color.NRGBA
+	ScrimBg      color.NRGBA // backdrop behind modal dialogs
+	MutedFg      color.NRGBA // for placeholder / hint text
+}
+
+func lightPalette() themePalette {
+	return themePalette{
+		Background:   color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff},
+		OnBackground: color.NRGBA{R: 0x10, G: 0x10, B: 0x10, A: 0xff},
+		Divider:      color.NRGBA{R: 0xe0, G: 0xe0, B: 0xe0, A: 0xff},
+		RingBg:       color.NRGBA{R: 0xd8, G: 0xd8, B: 0xd8, A: 0xff},
+		RingFg:       color.NRGBA{R: 0x10, G: 0x70, B: 0xff, A: 0xff},
+		RingFgWarn:   color.NRGBA{R: 0xd0, G: 0x30, B: 0x30, A: 0xff},
+		ToastBg:      color.NRGBA{R: 0x20, G: 0x20, B: 0x20, A: 0xe0},
+		ToastFg:      color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff},
+		ErrorFg:      color.NRGBA{R: 0xc0, G: 0x00, B: 0x00, A: 0xff},
+		DialogBg:     color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff},
+		DialogBorder: color.NRGBA{R: 0x55, G: 0x55, B: 0x55, A: 0xff},
+		ScrimBg:      color.NRGBA{R: 0x00, G: 0x00, B: 0x00, A: 0x60},
+		MutedFg:      color.NRGBA{R: 0x80, G: 0x80, B: 0x80, A: 0xff},
+	}
+}
+
+func darkPalette() themePalette {
+	return themePalette{
+		Background:   color.NRGBA{R: 0x1e, G: 0x1e, B: 0x1e, A: 0xff},
+		OnBackground: color.NRGBA{R: 0xf0, G: 0xf0, B: 0xf0, A: 0xff},
+		Divider:      color.NRGBA{R: 0x38, G: 0x38, B: 0x38, A: 0xff},
+		RingBg:       color.NRGBA{R: 0x3a, G: 0x3a, B: 0x3a, A: 0xff},
+		RingFg:       color.NRGBA{R: 0x4d, G: 0xa3, B: 0xff, A: 0xff},
+		RingFgWarn:   color.NRGBA{R: 0xff, G: 0x6b, B: 0x6b, A: 0xff},
+		ToastBg:      color.NRGBA{R: 0xf0, G: 0xf0, B: 0xf0, A: 0xee},
+		ToastFg:      color.NRGBA{R: 0x10, G: 0x10, B: 0x10, A: 0xff},
+		ErrorFg:      color.NRGBA{R: 0xff, G: 0x6b, B: 0x6b, A: 0xff},
+		DialogBg:     color.NRGBA{R: 0x2a, G: 0x2a, B: 0x2a, A: 0xff},
+		DialogBorder: color.NRGBA{R: 0x60, G: 0x60, B: 0x60, A: 0xff},
+		ScrimBg:      color.NRGBA{R: 0x00, G: 0x00, B: 0x00, A: 0x90},
+		MutedFg:      color.NRGBA{R: 0x90, G: 0x90, B: 0x90, A: 0xff},
+	}
+}
+
+// buildTheme returns a fresh material.Theme + companion palette for the
+// requested mode. "system" resolves via systemPrefersDark (Windows
+// registry on win, false elsewhere).
+func buildTheme(mode themeMode) (*material.Theme, themePalette) {
+	resolved := mode
+	if resolved == "" || resolved == themeSystem {
+		if systemPrefersDark() {
+			resolved = themeDark
+		} else {
+			resolved = themeLight
+		}
+	}
+	var pal themePalette
+	if resolved == themeDark {
+		pal = darkPalette()
+	} else {
+		pal = lightPalette()
+	}
+
+	th := material.NewTheme()
+	th.Shaper = text.NewShaper(text.WithCollection(gofont.Collection()))
+	th.Palette.Bg = pal.Background
+	th.Palette.Fg = pal.OnBackground
+	if resolved == themeDark {
+		th.Palette.ContrastBg = color.NRGBA{R: 0x4d, G: 0xa3, B: 0xff, A: 0xff}
+		th.Palette.ContrastFg = color.NRGBA{R: 0x10, G: 0x10, B: 0x10, A: 0xff}
+	}
+	return th, pal
+}
+
+// normalizeThemeMode coerces an arbitrary config string into one of the
+// known modes. Unknown values fall back to "system".
+func normalizeThemeMode(s string) themeMode {
+	switch themeMode(s) {
+	case themeLight, themeDark, themeSystem:
+		return themeMode(s)
+	}
+	return themeSystem
+}
+
+// activePalette holds the palette of the currently-rendered theme. Set
+// once per frame at the top of drawFrame so shared helpers (toast,
+// dividers, dialog backdrops) can colour themselves without dragging a
+// palette argument through every signature. Gio invokes drawFrame on
+// the single UI goroutine so plain assignment is safe.
+var activePalette = lightPalette()

internal/ui/theme_other.go

@@ -0,0 +1,7 @@
+//go:build !windows
+
+package ui
+
+// systemPrefersDark is the non-Windows stub; we cannot reliably read
+// the OS theme preference, so default to light.
+func systemPrefersDark() bool { return false }

internal/ui/theme_windows.go

@@ -0,0 +1,25 @@
+//go:build windows
+
+package ui
+
+import "golang.org/x/sys/windows/registry"
+
+// systemPrefersDark queries the Windows personalization registry key
+// to find out whether the user picked dark mode for apps. Returns
+// false on any read error so the default stays "light".
+func systemPrefersDark() bool {
+	k, err := registry.OpenKey(
+		registry.CURRENT_USER,
+		`Software\Microsoft\Windows\CurrentVersion\Themes\Personalize`,
+		registry.QUERY_VALUE,
+	)
+	if err != nil {
+		return false
+	}
+	defer k.Close()
+	v, _, err := k.GetIntegerValue("AppsUseLightTheme")
+	if err != nil {
+		return false
+	}
+	return v == 0
+}

internal/ui/toast.go

@@ -2,7 +2,6 @@ package ui
 
 import (
 	"image"
-	"image/color"
 	"time"
 
 	"gioui.org/app"
@@ -48,8 +47,8 @@ func (t *toast) draw(gtx layout.Context, th *material.Theme) {
 	if !t.active() {
 		return
 	}
-	bg := color.NRGBA{R: 0x20, G: 0x20, B: 0x20, A: 0xe0}
-	fg := color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff}
+	bg := activePalette.ToastBg
+	fg := activePalette.ToastFg
 
 	macro := op.Record(gtx.Ops)
 	pad := layout.UniformInset(unit.Dp(10))

internal/ui/vendor_menu.go

@@ -1,8 +1,6 @@
 package ui
 
 import (
-	"image/color"
-
 	"gioui.org/layout"
 	"gioui.org/unit"
 	"gioui.org/widget"
@@ -71,7 +69,7 @@ func (m *vendorMenu) Pick(gtx layout.Context) (vendor, bool) {
 }
 
 func (m *vendorMenu) Layout(gtx layout.Context, th *material.Theme) layout.Dimensions {
-	fillBackground(gtx, color.NRGBA{R: 0, G: 0, B: 0, A: 0x60})
+	fillBackground(gtx, activePalette.ScrimBg)
 
 	row := func(btn *widget.Clickable, label string) layout.FlexChild {
 		return layout.Rigid(func(gtx layout.Context) layout.Dimensions {
@@ -86,11 +84,11 @@ func (m *vendorMenu) Layout(gtx layout.Context, th *material.Theme) layout.Dimen
 	return layout.Center.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 		gtx.Constraints.Max.X = gtx.Dp(320)
 		return widget.Border{
-			Color:        color.NRGBA{R: 0x55, G: 0x55, B: 0x55, A: 0xff},
+			Color:        activePalette.DialogBorder,
 			CornerRadius: unit.Dp(4),
 			Width:        unit.Dp(1),
 		}.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
-			fillBackground(gtx, color.NRGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff})
+			fillBackground(gtx, activePalette.DialogBg)
 			return layout.UniformInset(unit.Dp(16)).Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 				return layout.Flex{Axis: layout.Vertical}.Layout(gtx,
 					layout.Rigid(material.H6(th, i18n.T("menu_choose_vendor")).Layout),

internal/version/version.go

@@ -0,0 +1,28 @@
+// Package version exposes build metadata. Defaults are placeholders for
+// dev builds; release builds inject real values via -ldflags:
+//
+//	-X git.wxccs.org/iceking2nd/winauth-go/internal/version.Version=1.2.3
+//	-X git.wxccs.org/iceking2nd/winauth-go/internal/version.Commit=abc1234
+//	-X git.wxccs.org/iceking2nd/winauth-go/internal/version.BuildDate=2026-06-12
+package version
+
+// Version is the human-readable release version ("1.2.3" or "dev").
+var Version = "dev"
+
+// Commit is the short git SHA the binary was built from. Empty in dev.
+var Commit = ""
+
+// BuildDate is the ISO date when the binary was built. Empty in dev.
+var BuildDate = ""
+
+// String returns a one-line summary suitable for an About dialog.
+func String() string {
+	s := Version
+	if Commit != "" {
+		s += " (" + Commit + ")"
+	}
+	if BuildDate != "" {
+		s += " — " + BuildDate
+	}
+	return s
+}