diff --git a/banner.go b/banner.go
new file mode 100644
index 0000000..db5f1e1
--- /dev/null
+++ b/banner.go
@@ -0,0 +1,56 @@
+package mujica
+
+import (
+	"log/slog"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/icons"
+	"mujicaui/theme"
+)
+
+// BannerOptions configure a Banner.
+type BannerOptions struct {
+	Severity Severity
+	// Action labels a button after the message; empty shows none.
+	Action string
+}
+
+// Banner is a full-width notice for the top of a page; a non-nil open adds a close button.
+func Banner(c *ui.Context, open *bool, message string, opts BannerOptions) AlertResult {
+	if message == "" {
+		panic("mujica: Banner needs a message")
+	}
+	k := Tokens(c)
+	tone, icon := severityLook(k, opts.Severity)
+	if open != nil && !*open {
+		return AlertResult{}
+	}
+	u := Density(c).Unit()
+	name := msg(c, "alert."+opts.Severity.String())
+	var res AlertResult
+	bar := ui.Row(c).FillWidth().MinHeight(Density(c).ControlHeight()+2*u).AlignItems(ui.Center).Gap(u*3).Padding(u*2, u*3, u*2, u*4).
+		Background(k.Surface.Mix(tone, 0.08)).Role(ui.RoleGroup).Label(name)
+	bar.Draw(func(p *ui.Painter, r ui.Rect) {
+		p.Fill(ui.Rect{X: r.X, Y: r.Y + r.H - 2, W: r.W, H: 2}, tone, 0)
+	})
+	said := ui.Local(bar, "banner.said", func() string { return "" })
+	if news := name + ": " + message; opts.Severity >= SeverityWarning && *said != news {
+		*said = news
+		c.Announce(news)
+	}
+	bar.Children(func() {
+		ui.Icon(c, icon).Size(20, 20).TextColor(tone)
+		ui.Text(c, message).TextColor(k.Text).Grow(1).Shrink(1).LineHeight(theme.LineHeight)
+		if opts.Action != "" && Button(c, opts.Action, ButtonOptions{Variant: Outline}).Clicked() {
+			slog.Debug("mujica: banner action", "severity", opts.Severity)
+			res.Action = true
+		}
+		if open != nil && iconAction(c, icons.Must("x"), msg(c, "alert.close")).Clicked() {
+			slog.Debug("mujica: banner closed", "severity", opts.Severity)
+			*open, res.Closed = false, true
+		}
+	})
+	res.Element = bar
+	return res
+}
diff --git a/banner_test.go b/banner_test.go
new file mode 100644
index 0000000..bba858e
--- /dev/null
+++ b/banner_test.go
@@ -0,0 +1,75 @@
+package mujica
+
+import (
+	"slices"
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+)
+
+func TestBannerActionCloseAndAnnounce(t *testing.T) {
+	open := true
+	var last AlertResult
+	tt := ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		if r := Banner(c, &open, "Maintenance tonight at 22:00", BannerOptions{Severity: SeverityWarning, Action: "Details"}); r.Action || r.Closed {
+			last = r
+		}
+	}, 700, 200)
+	if a := tt.Announcements(); !slices.Equal(a, []string{"Warning: Maintenance tonight at 22:00"}) {
+		t.Fatalf("announcements %q", a)
+	}
+	if err := tt.Click("Details"); err != nil {
+		t.Fatal(err)
+	}
+	if !last.Action || !open {
+		t.Fatalf("action: %+v open %v", last, open)
+	}
+	tt.Key(0, ui.KeyTab) // from Details to Dismiss
+	tt.Key(0, ui.KeyEnter)
+	if open || !last.Closed || tt.HasText("Maintenance") {
+		t.Fatalf("keyboard close: open %v %+v", open, last)
+	}
+}
+
+func TestBannerDisabledAndFixed(t *testing.T) {
+	open := true
+	tt := ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		ui.Column(c).Disabled(true).Children(func() {
+			Banner(c, &open, "Read only", BannerOptions{Severity: SeverityError})
+		})
+		Banner(c, nil, "Always here", BannerOptions{})
+	}, 700, 200)
+	_ = tt.Click("Dismiss")
+	if !open {
+		t.Fatal("disabled banner closed")
+	}
+	if !tt.HasText("Always here") {
+		t.Fatal("banner without open missing")
+	}
+	for _, f := range []func(c *ui.Context){
+		func(c *ui.Context) { Banner(c, nil, "", BannerOptions{}) },
+		func(c *ui.Context) { Banner(c, nil, "x", BannerOptions{Severity: 7}) },
+	} {
+		func() {
+			defer func() {
+				if recover() == nil {
+					t.Error("no panic")
+				}
+			}()
+			ui.NewTester(func(c *ui.Context) { Use(c, Settings{}); f(c) }, 300, 100)
+		}()
+	}
+}
+
+func TestBannerSnapshot(t *testing.T) {
+	open := true
+	snapshot(t, "banner", 640, 200, func(c *ui.Context) {
+		ui.Column(c).Gap(8).Children(func() {
+			Banner(c, &open, "A new version is available.", BannerOptions{Action: "Update"})
+			Banner(c, &open, "Your trial ends in 3 days.", BannerOptions{Severity: SeverityWarning})
+			Banner(c, nil, "Sync is failing; changes stay on this device.", BannerOptions{Severity: SeverityError, Action: "Retry"})
+		})
+	})
+}
diff --git a/copy_button.go b/copy_button.go
new file mode 100644
index 0000000..2dd07c9
--- /dev/null
+++ b/copy_button.go
@@ -0,0 +1,64 @@
+package mujica
+
+import (
+	"log/slog"
+	"time"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/icons"
+	"mujicaui/theme"
+)
+
+// copyButtonShown is how long the button says Copied.
+const copyButtonShown = 2 * time.Second
+
+// CopyButtonOptions configure a CopyButton.
+type CopyButtonOptions struct {
+	// Label shows beside the icon; empty makes a square icon button.
+	Label    string
+	Disabled bool
+}
+
+// CopyButton puts text on the clipboard, then shows and announces Copied for two seconds.
+func CopyButton(c *ui.Context, text string, opts CopyButtonOptions) ChoiceResult {
+	copied := msg(c, "copy_button.copied")
+	name := msg(c, "copy_button.copy")
+	label, icon := opts.Label, icons.Must("copy")
+	var b *ui.Element
+	box := ui.Box(c)
+	at := ui.Local(box, "copy_button.at", func() time.Time { return time.Time{} })
+	left := copyButtonShown - c.Now().Sub(*at)
+	done := !at.IsZero() && left > 0
+	if done {
+		icon, name = icons.Must("check"), copied
+		if label != "" {
+			label = copied
+		}
+		c.After(left)
+	}
+	box.Children(func() {
+		bo := ButtonOptions{Variant: Secondary, Icon: icon, Disabled: opts.Disabled}
+		if opts.Label == "" {
+			bo.Label = name
+		}
+		b = Button(c, label, bo)
+		if opts.Label == "" {
+			b.Padding(0).Size(Density(c).ControlHeight(), Density(c).ControlHeight()).Tooltip(name)
+		} else {
+			// Room for the longer word, so the width holds.
+			w1, _ := c.MeasureText(0, ui.Span{Text: copied})
+			w2, _ := c.MeasureText(0, ui.Span{Text: opts.Label})
+			b.MinWidth(max(w1, w2) + buttonSpinnerSize + Density(c).Unit()*10 + 2*theme.BorderWidth)
+		}
+	})
+	if b.Clicked() && !b.IsDisabled() {
+		c.WriteClipboard(text)
+		*at = c.Now()
+		c.Announce(copied)
+		c.Invalidate()
+		slog.Debug("mujica: copy_button copied", "bytes", len(text))
+		return ChoiceResult{box, true}
+	}
+	return ChoiceResult{box, false}
+}
diff --git a/copy_button_test.go b/copy_button_test.go
new file mode 100644
index 0000000..4e6d07b
--- /dev/null
+++ b/copy_button_test.go
@@ -0,0 +1,77 @@
+package mujica
+
+import (
+	"slices"
+	"testing"
+	"time"
+
+	"github.com/egoist/mygo/ui"
+)
+
+func TestCopyButtonCopiesAndAnnounces(t *testing.T) {
+	n := 0
+	var w float32
+	tt := ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		ui.Row(c).Children(func() {
+			r := CopyButton(c, "sk-live-123", CopyButtonOptions{Label: "Copy key"})
+			if r.Changed() {
+				n++
+			}
+			w = r.Element.Bounds().W
+		})
+	}, 400, 200)
+	tt.Frame()
+	before := w
+	if err := tt.Click("Copy key"); err != nil {
+		t.Fatal(err)
+	}
+	if tt.Clipboard() != "sk-live-123" || n != 1 {
+		t.Fatalf("clipboard %q, copies %d", tt.Clipboard(), n)
+	}
+	if !tt.HasText("Copied") || !slices.Contains(tt.Announcements(), "Copied") {
+		t.Fatalf("texts %q", tt.Texts())
+	}
+	tt.Frame()
+	if w != before {
+		t.Fatalf("width %v changed from %v", w, before)
+	}
+}
+
+func TestCopyButtonKeyboardRevertAndDisabled(t *testing.T) {
+	dis := false
+	tt := ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{Locale: ZhCN})
+		CopyButton(c, "abc", CopyButtonOptions{Disabled: dis})
+	}, 300, 200)
+	tt.Key(0, ui.KeyTab)
+	tt.Key(0, ui.KeySpace)
+	if tt.Clipboard() != "abc" {
+		t.Fatalf("Space copied %q", tt.Clipboard())
+	}
+	if _, ok := tt.Find("已复制"); !ok {
+		t.Fatal("icon button lacks the copied name")
+	}
+	time.Sleep(copyButtonShown + 50*time.Millisecond)
+	tt.Frame()
+	if _, ok := tt.Find("复制"); !ok {
+		t.Fatal("did not revert to Copy")
+	}
+	tt.SetClipboard("")
+	dis = true
+	tt.Frame()
+	_ = tt.Click("复制")
+	if tt.Clipboard() != "" {
+		t.Fatal("disabled button copied")
+	}
+}
+
+func TestCopyButtonSnapshot(t *testing.T) {
+	snapshot(t, "copy_button", 360, 80, func(c *ui.Context) {
+		ui.Row(c).Padding(16).Gap(12).Children(func() {
+			CopyButton(c, "x", CopyButtonOptions{})
+			CopyButton(c, "x", CopyButtonOptions{Label: "Copy link"})
+			CopyButton(c, "x", CopyButtonOptions{Label: "Copy", Disabled: true})
+		})
+	})
+}
diff --git a/messages_essentials.go b/messages_essentials.go
index 88cfc55..ca8dd7e 100644
--- a/messages_essentials.go
+++ b/messages_essentials.go
@@ -2,6 +2,11 @@ package mujica
 
 func init() {
 	addMessages(map[string][2]string{
+		"copy_button.copy":   {"Copy", "复制"},
+		"copy_button.copied": {"Copied", "已复制"},
+
+		"split_button.more": {"More options", "更多选项"},
+
 		"qr_code.label":    {"QR code", "二维码"},
 		"qr_code.too_long": {"Text too long for a QR code", "文字过长，无法生成二维码"},
 	})
diff --git a/split_button.go b/split_button.go
new file mode 100644
index 0000000..200d60a
--- /dev/null
+++ b/split_button.go
@@ -0,0 +1,86 @@
+package mujica
+
+import (
+	"fmt"
+	"log/slog"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/icons"
+	"mujicaui/internal"
+	"mujicaui/theme"
+)
+
+// SplitButtonOptions configure a SplitButton.
+type SplitButtonOptions struct {
+	// Variant is Primary (the zero value) or Secondary.
+	Variant ButtonVariant
+	Icon    *ui.SVG
+	// MenuLabel names the menu half; empty uses "More options".
+	MenuLabel string
+	Disabled  bool
+}
+
+// SplitButton runs its main action from the left half and opens build's menu from the right; each half takes focus.
+func SplitButton(c *ui.Context, label string, opts SplitButtonOptions, build func(m *PopupMenu)) ChoiceResult {
+	if label == "" || build == nil {
+		panic("mujica: SplitButton needs a label and a menu")
+	}
+	if opts.Variant != Primary && opts.Variant != Secondary {
+		panic(fmt.Sprintf("mujica: SplitButton Variant %d must be Primary or Secondary", opts.Variant))
+	}
+	k := Tokens(c)
+	d := Density(c)
+	menuName := opts.MenuLabel
+	if menuName == "" {
+		menuName = msg(c, "split_button.more")
+	}
+	group := ui.Row(c).AlignItems(ui.Stretch).Disabled(opts.Disabled)
+	disabled := group.IsDisabled()
+	open := ui.Local(group, "split_button.open", func() bool { return false })
+	if disabled {
+		*open = false
+	}
+	var clicked bool
+	group.Children(func() {
+		main := ui.ButtonBase(c).MinHeight(d.ControlHeight()).Padding(0, d.Unit()*4).Gap(d.Unit()*2).
+			Radius(theme.ControlRadius, 0, 0, theme.ControlRadius)
+		splitButtonLook(c, k, main, opts.Variant, false)
+		main.Children(func() {
+			if opts.Icon != nil {
+				ui.Icon(c, opts.Icon).Size(16, 16)
+			}
+			ui.Text(c, label).SingleLine()
+		})
+		clicked = main.Clicked() && !disabled
+		if opts.Variant == Primary {
+			ui.Box(c).Width(theme.BorderWidth).Background(k.OnAccent.Alpha(0.45)).Role(ui.RoleNone)
+		}
+		more := ui.ButtonBase(c).Role(ui.RoleMenuButton).Label(menuName).MinHeight(d.ControlHeight()).Width(theme.MinHitSize+d.Unit()).
+			Radius(0, theme.ControlRadius, theme.ControlRadius, 0).Tooltip(menuName)
+		splitButtonLook(c, k, more, opts.Variant, *open)
+		if opts.Variant == Secondary {
+			more.BorderWidth(theme.BorderWidth, theme.BorderWidth, theme.BorderWidth, 0)
+		}
+		more.Children(func() { ui.Icon(c, icons.Must("chevron-down")).Size(14, 14) })
+		if !disabled && (more.Clicked() || more.Shortcut(0, ui.KeyDown)) {
+			*open = true
+			slog.Debug("mujica: split_button open")
+		}
+		popupMenuOpen(c, group, open, build)
+	})
+	if clicked {
+		slog.Debug("mujica: split_button action", "label", label)
+	}
+	return ChoiceResult{group, clicked}
+}
+
+// splitButtonLook colors one half as a Button of variant v would be.
+func splitButtonLook(c *ui.Context, k theme.Tokens, b *ui.Element, v ButtonVariant, open bool) {
+	internal.Ring(b, k.Focus, theme.ControlRadius)
+	bg, fg, border := buttonColors(k, v, b.Hovered() && !b.IsDisabled(), b.Pressed() || open)
+	b.Background(bg).TextColor(fg).Transition(colorFade)
+	if border.A > 0 {
+		b.Border(theme.BorderWidth, border)
+	}
+}
diff --git a/split_button_test.go b/split_button_test.go
new file mode 100644
index 0000000..166d2c1
--- /dev/null
+++ b/split_button_test.go
@@ -0,0 +1,99 @@
+package mujica
+
+import (
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+)
+
+func splitButtonTester(dis *bool, runs *int, chosen *string) *ui.Tester {
+	return ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		ui.Row(c).Padding(20).Children(func() {
+			r := SplitButton(c, "Save", SplitButtonOptions{Disabled: *dis}, func(m *PopupMenu) {
+				for _, s := range []string{"Save as…", "Save all"} {
+					if m.Item(s, PopupMenuItemOptions{}) {
+						*chosen = s
+					}
+				}
+			})
+			if r.Changed() {
+				*runs++
+			}
+		})
+	}, 500, 300)
+}
+
+func TestSplitButtonMainAndMenu(t *testing.T) {
+	dis, runs, chosen := false, 0, ""
+	tt := splitButtonTester(&dis, &runs, &chosen)
+	if err := tt.Click("Save"); err != nil {
+		t.Fatal(err)
+	}
+	if runs != 1 || tt.HasText("Save all") {
+		t.Fatalf("main click: runs %d, menu open %v", runs, tt.HasText("Save all"))
+	}
+	if err := tt.Click("More options"); err != nil {
+		t.Fatal(err)
+	}
+	if err := tt.Click("Save all"); err != nil {
+		t.Fatal(err)
+	}
+	if chosen != "Save all" || runs != 1 || tt.HasText("Save as…") {
+		t.Fatalf("menu choice %q runs %d", chosen, runs)
+	}
+}
+
+func TestSplitButtonKeyboardHalves(t *testing.T) {
+	dis, runs, chosen := false, 0, ""
+	tt := splitButtonTester(&dis, &runs, &chosen)
+	tt.Key(0, ui.KeyTab)
+	if !tt.Focused("Save") {
+		t.Fatal("first Tab misses the main half")
+	}
+	tt.Key(0, ui.KeyEnter)
+	tt.Key(0, ui.KeyTab)
+	if !tt.Focused("More options") {
+		t.Fatal("second Tab misses the menu half")
+	}
+	tt.Key(0, ui.KeyDown)
+	if runs != 1 || !tt.HasText("Save as…") {
+		t.Fatalf("runs %d, menu %v", runs, tt.HasText("Save as…"))
+	}
+	tt.Key(0, ui.KeyEnter)
+	if chosen != "Save as…" {
+		t.Fatalf("Enter chose %q", chosen)
+	}
+}
+
+func TestSplitButtonDisabled(t *testing.T) {
+	dis, runs, chosen := true, 0, ""
+	tt := splitButtonTester(&dis, &runs, &chosen)
+	_ = tt.Click("Save")
+	_ = tt.Click("More options")
+	tt.Key(0, ui.KeyTab)
+	tt.Key(0, ui.KeyEnter)
+	if runs != 0 || tt.HasText("Save all") {
+		t.Fatalf("disabled: runs %d menu %v", runs, tt.HasText("Save all"))
+	}
+	defer func() {
+		if recover() == nil {
+			t.Fatal("Danger variant accepted")
+		}
+	}()
+	ui.NewTester(func(c *ui.Context) {
+		Use(c, Settings{})
+		SplitButton(c, "x", SplitButtonOptions{Variant: Danger}, func(*PopupMenu) {})
+	}, 200, 100)
+}
+
+func TestSplitButtonSnapshot(t *testing.T) {
+	snapshot(t, "split_button", 460, 80, func(c *ui.Context) {
+		ui.Row(c).Padding(16).Gap(12).Children(func() {
+			menu := func(m *PopupMenu) { m.Item("Other", PopupMenuItemOptions{}) }
+			SplitButton(c, "Publish", SplitButtonOptions{}, menu)
+			SplitButton(c, "Export", SplitButtonOptions{Variant: Secondary}, menu)
+			SplitButton(c, "Merge", SplitButtonOptions{Disabled: true}, menu)
+		})
+	})
+}
diff --git a/testdata/snapshots/darwin/banner-dark.png b/testdata/snapshots/darwin/banner-dark.png
new file mode 100644
index 0000000..9ec220a
Binary files /dev/null and b/testdata/snapshots/darwin/banner-dark.png differ
diff --git a/testdata/snapshots/darwin/banner-light.png b/testdata/snapshots/darwin/banner-light.png
new file mode 100644
index 0000000..c465661
Binary files /dev/null and b/testdata/snapshots/darwin/banner-light.png differ
diff --git a/testdata/snapshots/darwin/copy_button-dark.png b/testdata/snapshots/darwin/copy_button-dark.png
new file mode 100644
index 0000000..b059394
Binary files /dev/null and b/testdata/snapshots/darwin/copy_button-dark.png differ
diff --git a/testdata/snapshots/darwin/copy_button-light.png b/testdata/snapshots/darwin/copy_button-light.png
new file mode 100644
index 0000000..f5668c3
Binary files /dev/null and b/testdata/snapshots/darwin/copy_button-light.png differ
diff --git a/testdata/snapshots/darwin/split_button-dark.png b/testdata/snapshots/darwin/split_button-dark.png
new file mode 100644
index 0000000..a198882
Binary files /dev/null and b/testdata/snapshots/darwin/split_button-dark.png differ
diff --git a/testdata/snapshots/darwin/split_button-light.png b/testdata/snapshots/darwin/split_button-light.png
new file mode 100644
index 0000000..892ce9e
Binary files /dev/null and b/testdata/snapshots/darwin/split_button-light.png differ