{
    let device_refresh_button = gtk::Button::with_label("Refresh Devices");
    stabilize_button(&device_refresh_button, 132);
    device_refresh_button.set_tooltip_text(Some("Re-scan connected devices."));
    let (devices_panel, devices_body) =
        build_panel_with_action("Device Staging", Some(device_refresh_button.upcast_ref()));
    devices_panel.set_hexpand(false);
    devices_panel.set_size_request(DEVICE_STAGING_PANEL_WIDTH, -1);
    devices_panel.set_vexpand(true);
    devices_panel.set_valign(gtk::Align::Fill);
    devices_body.set_vexpand(true);
    devices_body.set_spacing(8);

    let control_group = build_subgroup("Control Inputs");
    let control_stack = gtk::Box::new(gtk::Orientation::Vertical, 10);
    control_group.append(&control_stack);

    let camera_combo = gtk::ComboBoxText::new();
    camera_combo.add_css_class("compact-combo");
    install_device_choice_combo_behavior(&camera_combo);
    sync_stage_device_combo(
        &camera_combo,
        &catalog.cameras,
        state.devices.camera.as_deref(),
    );
    let camera_quality_combo = gtk::ComboBoxText::new();
    camera_quality_combo.add_css_class("compact-combo");
    sync_camera_quality_combo(
        &camera_quality_combo,
        &state.camera_quality_options(catalog),
        state.selected_camera_quality(catalog),
    );
    camera_quality_combo.set_size_request(88, -1);
    camera_quality_combo.set_tooltip_text(Some("Webcam uplink quality."));
    let camera_test_button = gtk::Button::with_label("Start Preview");
    stabilize_button(&camera_test_button, 118);
    camera_test_button.set_tooltip_text(Some("Preview selected webcam locally."));

    let speaker_combo = gtk::ComboBoxText::new();
    speaker_combo.add_css_class("compact-combo");
    install_device_choice_combo_behavior(&speaker_combo);
    sync_stage_device_combo(
        &speaker_combo,
        &catalog.speakers,
        state.devices.speaker.as_deref(),
    );
    let speaker_test_button = gtk::Button::with_label("Play Tone");
    stabilize_button(&speaker_test_button, 118);
    speaker_test_button.set_tooltip_text(Some("Play a local test tone."));

    let keyboard_combo = gtk::ComboBoxText::new();
    keyboard_combo.add_css_class("compact-combo");
    install_device_choice_combo_behavior(&keyboard_combo);
    keyboard_combo.append(Some("all"), "all keyboards");
    for keyboard in &catalog.keyboards {
        append_input_choice(&keyboard_combo, keyboard);
    }
    super::ui_runtime::set_combo_active_text(&keyboard_combo, state.devices.keyboard.as_deref());
    keyboard_combo.set_tooltip_text(Some("Keyboard source for relay input."));
    let keyboard_row = build_inline_selector_row("Keyboard", &keyboard_combo);
    control_stack.append(&keyboard_row);

    let mouse_combo = gtk::ComboBoxText::new();
    mouse_combo.add_css_class("compact-combo");
    install_device_choice_combo_behavior(&mouse_combo);
    mouse_combo.append(Some("all"), "all mice");
    for mouse in &catalog.mice {
        append_input_choice(&mouse_combo, mouse);
    }
    super::ui_runtime::set_combo_active_text(&mouse_combo, state.devices.mouse.as_deref());
    mouse_combo.set_tooltip_text(Some("Pointer source for relay input."));
    let mouse_row = build_inline_selector_row("Mouse", &mouse_combo);
    control_stack.append(&mouse_row);
    devices_body.append(&control_group);

    let media_group = build_subgroup("Media Controls");
    media_group.set_vexpand(true);
    media_group.set_valign(gtk::Align::Fill);
    let media_grid = gtk::Grid::new();
    media_grid.set_row_spacing(10);
    media_grid.set_column_spacing(8);
    media_group.append(&media_grid);
    let camera_channel_toggle = gtk::ToggleButton::with_label("Camera");
    camera_channel_toggle.set_active(state.channels.camera);
    camera_channel_toggle.set_tooltip_text(Some("Send webcam during relay."));
    camera_channel_toggle.add_css_class("pill-toggle");
    camera_channel_toggle.add_css_class("media-toggle");
    stabilize_button(&camera_channel_toggle, 92);
    let audio_channel_toggle = gtk::ToggleButton::with_label("Speaker");
    audio_channel_toggle.set_active(state.channels.audio);
    audio_channel_toggle.set_tooltip_text(Some("Play remote audio here."));
    audio_channel_toggle.add_css_class("pill-toggle");
    audio_channel_toggle.add_css_class("media-toggle");
    stabilize_button(&audio_channel_toggle, 92);
    let microphone_channel_toggle = gtk::ToggleButton::with_label("Mic");
    microphone_channel_toggle.set_active(state.channels.microphone);
    microphone_channel_toggle.set_tooltip_text(Some("Send mic during relay."));
    microphone_channel_toggle.add_css_class("pill-toggle");
    microphone_channel_toggle.add_css_class("media-toggle");
    microphone_channel_toggle.add_css_class("media-toggle-split");
    stabilize_button(&microphone_channel_toggle, 44);
    let noise_suppression_toggle = gtk::ToggleButton::with_label("🧹");
    noise_suppression_toggle.set_active(state.mic_noise_suppression);
    noise_suppression_toggle.set_tooltip_text(Some(if state.mic_noise_suppression {
        "Noise cancellation is on for the upstream microphone."
    } else {
        "Noise cancellation is off; upstream microphone is raw aside from gain."
    }));
    noise_suppression_toggle.add_css_class("pill-toggle");
    noise_suppression_toggle.add_css_class("media-toggle");
    noise_suppression_toggle.add_css_class("media-toggle-split");
    stabilize_button(&noise_suppression_toggle, 44);

    let audio_gain_adjustment = gtk::Adjustment::new(
        f64::from(state.audio_gain_percent),
        0.0,
        f64::from(super::state::MAX_AUDIO_GAIN_PERCENT),
        25.0,
        100.0,
        0.0,
    );
    let audio_gain_scale =
        gtk::Scale::new(gtk::Orientation::Horizontal, Some(&audio_gain_adjustment));
    audio_gain_scale.set_draw_value(false);
    audio_gain_scale.set_hexpand(false);
    audio_gain_scale.set_size_request(96, -1);
    audio_gain_scale.set_tooltip_text(Some("Speaker volume. Double-click resets to 200%."));
    attach_scale_reset_gesture(
        &audio_gain_scale,
        f64::from(super::state::DEFAULT_AUDIO_GAIN_PERCENT),
    );
    let audio_gain_value = gtk::Label::new(Some(&state.audio_gain_label()));
    audio_gain_value.set_visible(false);

    let mic_gain_adjustment = gtk::Adjustment::new(
        f64::from(state.mic_gain_percent),
        0.0,
        f64::from(super::state::MAX_MIC_GAIN_PERCENT),
        25.0,
        100.0,
        0.0,
    );
    let mic_gain_scale = gtk::Scale::new(gtk::Orientation::Horizontal, Some(&mic_gain_adjustment));
    mic_gain_scale.set_draw_value(false);
    mic_gain_scale.set_hexpand(false);
    mic_gain_scale.set_size_request(96, -1);
    mic_gain_scale.set_tooltip_text(Some("Mic gain. Double-click resets to 100%."));
    attach_scale_reset_gesture(
        &mic_gain_scale,
        f64::from(super::state::DEFAULT_MIC_GAIN_PERCENT),
    );
    let mic_gain_value = gtk::Label::new(Some(&state.mic_gain_label()));
    mic_gain_value.set_visible(false);

    camera_combo.set_size_request(0, -1);
    let camera_selectors = gtk::Box::new(gtk::Orientation::Horizontal, 6);
    camera_combo.set_hexpand(true);
    camera_quality_combo.set_hexpand(false);
    camera_selectors.append(&camera_combo);
    camera_selectors.append(&camera_quality_combo);
    speaker_combo.set_size_request(0, -1);
    attach_device_control_row(
        &media_grid,
        0,
        &camera_channel_toggle,
        &camera_selectors,
        &camera_test_button,
    );
    let speaker_selectors = gtk::Box::new(gtk::Orientation::Horizontal, 6);
    speaker_combo.set_hexpand(true);
    speaker_selectors.append(&speaker_combo);
    speaker_selectors.append(&audio_gain_scale);
    attach_device_control_row(
        &media_grid,
        1,
        &audio_channel_toggle,
        &speaker_selectors,
        &speaker_test_button,
    );

    let microphone_combo = gtk::ComboBoxText::new();
    microphone_combo.add_css_class("compact-combo");
    install_device_choice_combo_behavior(&microphone_combo);
    sync_stage_device_combo(
        &microphone_combo,
        &catalog.microphones,
        state.devices.microphone.as_deref(),
    );
    let microphone_test_button = gtk::Button::with_label("Monitor Mic");
    stabilize_button(&microphone_test_button, 118);
    microphone_test_button.set_tooltip_text(Some("Monitor mic through speaker."));
    microphone_combo.set_size_request(0, -1);
    let microphone_selectors = gtk::Box::new(gtk::Orientation::Horizontal, 6);
    microphone_combo.set_hexpand(true);
    microphone_selectors.append(&microphone_combo);
    microphone_selectors.append(&mic_gain_scale);
    let microphone_toggle_group = gtk::Box::new(gtk::Orientation::Horizontal, 4);
    microphone_toggle_group.set_homogeneous(true);
    microphone_toggle_group.set_size_request(92, -1);
    microphone_toggle_group.append(&microphone_channel_toggle);
    microphone_toggle_group.append(&noise_suppression_toggle);
    attach_device_control_row(
        &media_grid,
        2,
        &microphone_toggle_group,
        &microphone_selectors,
        &microphone_test_button,
    );

    let audio_check_detail = gtk::Label::new(Some("Idle"));
    audio_check_detail.add_css_class("dim-label");
    audio_check_detail.set_wrap(false);
    audio_check_detail.set_ellipsize(pango::EllipsizeMode::End);
    audio_check_detail.set_xalign(0.0);
    audio_check_detail.set_visible(false);
    let audio_check_meter = gtk::ProgressBar::new();
    audio_check_meter.add_css_class("audio-check-meter");
    audio_check_meter.set_show_text(false);
    devices_body.append(&media_group);
    staging_row.append(&devices_panel);

    let upstream_transport_row = gtk::Box::new(gtk::Orientation::Horizontal, 6);
    upstream_transport_row.set_halign(gtk::Align::End);

    let webcam_transport_combo = gtk::ComboBoxText::new();
    webcam_transport_combo.add_css_class("compact-combo");
    for transport in [WebcamTransport::Mjpeg, WebcamTransport::Hevc] {
        webcam_transport_combo.append(Some(transport.as_id()), transport.label());
    }
    webcam_transport_combo.set_active_id(Some(state.effective_webcam_transport().as_id()));
    webcam_transport_combo.set_sensitive(true);
    webcam_transport_combo.set_size_request(98, -1);
    webcam_transport_combo.set_tooltip_text(Some(
        "Upstream webcam transport for the next relay connection. MJPEG is the safe calibrated default; HEVC is selectable for hardware-accelerated testing.",
    ));

    let upstream_audio_transport_combo = gtk::ComboBoxText::new();
    upstream_audio_transport_combo.add_css_class("compact-combo");
    for transport in [UpstreamAudioTransport::Pcm, UpstreamAudioTransport::Opus] {
        upstream_audio_transport_combo.append(Some(transport.as_id()), transport.label());
    }
    upstream_audio_transport_combo.set_active_id(Some(state.upstream_audio_transport.as_id()));
    upstream_audio_transport_combo.set_sensitive(true);
    upstream_audio_transport_combo.set_size_request(88, -1);
    upstream_audio_transport_combo.set_tooltip_text(Some(
        "Upstream microphone transport for the live relay. PCM is the known-good default; Opus is compressed and experimental.",
    ));

    upstream_transport_row.append(&webcam_transport_combo);
    upstream_transport_row.append(&upstream_audio_transport_combo);

    let (preview_panel, preview_body) =
        build_panel_with_action("Upstream Media", Some(upstream_transport_row.upcast_ref()));
    preview_panel.set_hexpand(true);
    preview_panel.set_vexpand(true);
    preview_panel.set_valign(gtk::Align::Fill);
    preview_body.set_hexpand(true);
    preview_body.set_vexpand(true);
    preview_body.set_spacing(8);
    let testing_row = gtk::Box::new(gtk::Orientation::Horizontal, 8);
    testing_row.set_hexpand(true);
    testing_row.set_vexpand(true);
    testing_row.set_valign(gtk::Align::Fill);
    let camera_preview = gtk::Picture::new();
    camera_preview.set_can_shrink(true);
    camera_preview.set_hexpand(true);
    camera_preview.set_vexpand(true);
    camera_preview.set_halign(gtk::Align::Fill);
    camera_preview.set_valign(gtk::Align::Fill);
    camera_preview.set_size_request(
        CAMERA_PREVIEW_VIEWPORT_WIDTH,
        CAMERA_PREVIEW_VIEWPORT_HEIGHT,
    );
    camera_preview.set_keep_aspect_ratio(true);
    camera_preview.add_css_class("camera-preview-frame");
    let camera_preview_idle = gtk::Picture::new();
    camera_preview_idle.set_can_shrink(true);
    camera_preview_idle.set_hexpand(true);
    camera_preview_idle.set_vexpand(true);
    camera_preview_idle.set_halign(gtk::Align::Fill);
    camera_preview_idle.set_valign(gtk::Align::Fill);
    camera_preview_idle.set_keep_aspect_ratio(true);
    camera_preview_idle.add_css_class("display-placeholder-art");
    camera_preview_idle.set_paintable(Some(&super::device_test::camera_preview_placeholder_texture()));
    let camera_mirror_button = gtk::ToggleButton::new();
    camera_mirror_button.add_css_class("camera-preview-mirror-toggle");
    camera_mirror_button.add_css_class("flat");
    camera_mirror_button.set_focus_on_click(false);
    camera_mirror_button.set_halign(gtk::Align::End);
    camera_mirror_button.set_valign(gtk::Align::Start);
    camera_mirror_button.set_margin_top(10);
    camera_mirror_button.set_margin_end(10);
    camera_mirror_button.set_tooltip_text(Some("Mirror launcher preview only."));
    camera_mirror_button.set_visible(false);
    let camera_mirror_icon = gtk::Image::from_icon_name("object-flip-horizontal-symbolic");
    camera_mirror_button.set_child(Some(&camera_mirror_icon));
    let camera_mirror_revealer = gtk::Revealer::new();
    camera_mirror_revealer.set_transition_type(gtk::RevealerTransitionType::Crossfade);
    camera_mirror_revealer.set_transition_duration(120);
    camera_mirror_revealer.set_halign(gtk::Align::End);
    camera_mirror_revealer.set_valign(gtk::Align::Start);
    camera_mirror_revealer.set_reveal_child(false);
    camera_mirror_revealer.set_child(Some(&camera_mirror_button));
    let camera_status = gtk::Label::new(Some("Select a webcam and click Start Preview."));
    camera_status.add_css_class("dim-label");
    camera_status.set_wrap(false);
    camera_status.set_ellipsize(pango::EllipsizeMode::End);
    camera_status.set_xalign(0.0);
    camera_status.set_visible(false);
    let camera_preview_shell = gtk::Box::new(gtk::Orientation::Vertical, 0);
    camera_preview_shell.set_hexpand(true);
    camera_preview_shell.set_vexpand(true);
    camera_preview_shell.set_halign(gtk::Align::Fill);
    camera_preview_shell.set_valign(gtk::Align::Fill);
    camera_preview_shell.set_size_request(
        CAMERA_PREVIEW_VIEWPORT_WIDTH,
        CAMERA_PREVIEW_VIEWPORT_HEIGHT,
    );
    let camera_preview_frame = gtk::AspectFrame::new(0.5, 0.5, 16.0 / 9.0, false);
    camera_preview_frame.set_hexpand(true);
    camera_preview_frame.set_vexpand(true);
    camera_preview_frame.set_halign(gtk::Align::Fill);
    camera_preview_frame.set_valign(gtk::Align::Fill);
    camera_preview_frame.set_size_request(
        CAMERA_PREVIEW_VIEWPORT_WIDTH,
        CAMERA_PREVIEW_VIEWPORT_HEIGHT,
    );
    camera_preview_frame.set_child(Some(&camera_preview));
    let camera_preview_overlay = gtk::Overlay::new();
    camera_preview_overlay.set_hexpand(true);
    camera_preview_overlay.set_vexpand(true);
    camera_preview_overlay.set_halign(gtk::Align::Fill);
    camera_preview_overlay.set_valign(gtk::Align::Fill);
    camera_preview_overlay.set_size_request(
        CAMERA_PREVIEW_VIEWPORT_WIDTH,
        CAMERA_PREVIEW_VIEWPORT_HEIGHT,
    );
    camera_preview_overlay.set_child(Some(&camera_preview_frame));
    camera_preview_overlay.add_overlay(&camera_mirror_revealer);
    let hover_revealer = camera_mirror_revealer.clone();
    let hover_button = camera_mirror_button.clone();
    let hover_controller = gtk::EventControllerMotion::new();
    hover_controller.connect_enter(move |_, _, _| {
        if hover_button.is_visible() {
            hover_revealer.set_reveal_child(true);
        }
    });
    let leave_revealer = camera_mirror_revealer.clone();
    let leave_button = camera_mirror_button.clone();
    hover_controller.connect_leave(move |_| {
        if leave_button.is_visible() {
            leave_revealer.set_reveal_child(false);
        }
    });
    camera_preview_overlay.add_controller(hover_controller);
    let camera_preview_idle_frame = gtk::AspectFrame::new(0.5, 0.5, 16.0 / 9.0, false);
    camera_preview_idle_frame.set_hexpand(true);
    camera_preview_idle_frame.set_vexpand(true);
    camera_preview_idle_frame.set_halign(gtk::Align::Fill);
    camera_preview_idle_frame.set_valign(gtk::Align::Fill);
    camera_preview_idle_frame.set_size_request(
        CAMERA_PREVIEW_VIEWPORT_WIDTH,
        CAMERA_PREVIEW_VIEWPORT_HEIGHT,
    );
    camera_preview_idle_frame.set_child(Some(&camera_preview_idle));
    let camera_preview_idle_shell = gtk::Box::new(gtk::Orientation::Vertical, 0);
    camera_preview_idle_shell.set_hexpand(true);
    camera_preview_idle_shell.set_vexpand(true);
    camera_preview_idle_shell.set_halign(gtk::Align::Fill);
    camera_preview_idle_shell.set_valign(gtk::Align::Fill);
    camera_preview_idle_shell.append(&camera_preview_idle_frame);
    let camera_preview_stack = gtk::Stack::new();
    camera_preview_stack.set_hexpand(true);
    camera_preview_stack.set_vexpand(true);
    camera_preview_stack.set_halign(gtk::Align::Fill);
    camera_preview_stack.set_valign(gtk::Align::Fill);
    camera_preview_stack.set_size_request(
        CAMERA_PREVIEW_VIEWPORT_WIDTH,
        CAMERA_PREVIEW_VIEWPORT_HEIGHT,
    );
    camera_preview_stack.add_named(&camera_preview_idle_shell, Some("idle"));
    camera_preview_stack.add_named(&camera_preview_overlay, Some("live"));
    camera_preview_stack.set_visible_child_name("idle");
    camera_preview_shell.append(&camera_preview_stack);
    let webcam_group = build_subgroup("Webcam Preview");
    webcam_group.set_hexpand(true);
    webcam_group.set_vexpand(true);
    webcam_group.set_valign(gtk::Align::Fill);
    webcam_group.append(&camera_preview_shell);
    testing_row.append(&webcam_group);

    let playback_group = build_subgroup("Mic Playback");
    playback_group.set_hexpand(false);
    playback_group.set_vexpand(true);
    playback_group.set_valign(gtk::Align::Fill);
    playback_group.set_size_request(72, -1);
    let playback_body = gtk::Box::new(gtk::Orientation::Vertical, 6);
    playback_body.set_halign(gtk::Align::Center);
    playback_body.set_vexpand(true);
    playback_body.set_valign(gtk::Align::Fill);
    let microphone_replay_button = gtk::Button::with_label("Replay");
    stabilize_button(&microphone_replay_button, 70);
    audio_check_meter.set_orientation(gtk::Orientation::Vertical);
    audio_check_meter.set_inverted(true);
    audio_check_meter.set_hexpand(false);
    audio_check_meter.set_vexpand(true);
    audio_check_meter.set_halign(gtk::Align::Center);
    audio_check_meter.set_size_request(20, 0);
    audio_check_meter.set_show_text(false);
    audio_check_meter.set_text(Some("Idle"));
    playback_body.append(&audio_check_meter);
    playback_body.append(&microphone_replay_button);
    playback_group.append(&playback_body);
    testing_row.append(&playback_group);
    preview_body.append(&testing_row);
    staging_row.append(&preview_panel);

    DeviceControlsContext {
        device_refresh_button,
        camera_combo,
        camera_quality_combo,
        microphone_combo,
        speaker_combo,
        keyboard_combo,
        mouse_combo,
        camera_channel_toggle,
        microphone_channel_toggle,
        noise_suppression_toggle,
        audio_channel_toggle,
        audio_gain_scale,
        audio_gain_value,
        mic_gain_scale,
        mic_gain_value,
        audio_check_detail,
        audio_check_meter,
        devices_panel,
        preview_panel,
        camera_preview_stack,
        camera_preview_frame,
        camera_preview,
        webcam_transport_combo,
        upstream_audio_transport_combo,
        camera_mirror_button,
        camera_mirror_revealer,
        camera_status,
        camera_test_button,
        microphone_test_button,
        microphone_replay_button,
        speaker_test_button,
    }
}