func (p TabViewPainter) PaintTabBar(canvas widget.Canvas, ps tabview.PaintState) {
	if ps.Bounds.IsEmpty() {
		return
	}

	// Determine the color scheme to use.
	colors := ps.ColorScheme
	if colors == (tabview.TabColorScheme{}) {
		colors = p.resolveColors()
	}

	// Tab bar background.
	canvas.DrawRect(ps.Bounds, colors.Background)

	// Draw each tab.
	for i := range ps.Tabs {
		ts := &ps.Tabs[i]
		m3PaintTab(canvas, ts, colors)
	}

	// Draw indicator under/over selected tab.
	if ps.SelectedIdx >= 0 && ps.SelectedIdx < len(ps.Tabs) {
		selected := &ps.Tabs[ps.SelectedIdx]
		m3PaintIndicator(canvas, selected.Bounds, ps.Position, colors.Indicator)
	}

	// Focus ring.
	if ps.Focused {
		ringBounds := ps.Bounds.Expand(m3TabFocusRingOffset)
		canvas.StrokeRoundRect(ringBounds, colors.FocusRing, m3TabFocusRadius, m3TabFocusRingStroke)
	}
}

type TabViewPainter struct {
	Theme *Theme	// nil uses default M3 purple fallback
}