diff --git a/flake.nix b/flake.nix
index 59923e4..78d1911 100644
--- a/flake.nix
+++ b/flake.nix
@@ -23,6 +23,7 @@
               pkg-config
               rust-analyzer
               rustfmt
+              rustc
               cargo
               clippy
             ];
diff --git a/src/daw.rs b/src/daw.rs
index 6f6bc5f..b338b78 100644
--- a/src/daw.rs
+++ b/src/daw.rs
@@ -1,4 +1,6 @@
-use gpui::{AppContext, Context, ScrollHandle, Task, point, px};
+use gpui::{AppContext, Context, Entity, ScrollHandle, Task, point, px};
+
+use crate::ui::core::slider::Slider;
 use std::time::{Duration, Instant};
 
 use crate::audio::{AudioEngine, SampleType};
@@ -25,10 +27,12 @@ pub struct Daw {
     pub bpm_drag_origin: Option<(f32, u32)>,
     /// Scroll handle for the pattern editor — used to auto-follow the playhead.
     pub pattern_scroll: ScrollHandle,
+    pub master_vol: f32,
+    pub master_slider: Entity<Slider>,
 }
 
 impl Daw {
-    pub fn new() -> Self {
+    pub fn new(cx: &mut gpui::Context<Self>) -> Self {
         let audio = AudioEngine::start();
         if audio.is_none() {
             eprintln!("warning: no audio device found, sequencer will be silent");
@@ -98,6 +102,18 @@ impl Daw {
             selected_track: None,
             bpm_drag_origin: None,
             pattern_scroll: ScrollHandle::default(),
+            master_vol: 0.72,
+            master_slider: {
+                let daw_entity = cx.entity();
+                cx.new(|_| {
+                    Slider::new(0.72).on_change(move |val, app| {
+                        app.update_entity(&daw_entity, |daw, cx| {
+                            daw.master_vol = val;
+                            cx.notify();
+                        });
+                    })
+                })
+            },
             tracks: vec![
                 Track {
                     name: "Kick".into(),
diff --git a/src/main.rs b/src/main.rs
index 6dcf695..fdc2a74 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,7 +24,7 @@ fn main() {
                 ..Default::default()
             },
             move |_, cx| {
-                let entity = cx.new(|_| Daw::new());
+                let entity = cx.new(|cx| Daw::new(cx));
                 *slot_fill.borrow_mut() = Some(entity.clone());
                 entity
             },
diff --git a/src/ui/core/mod.rs b/src/ui/core/mod.rs
new file mode 100644
index 0000000..1e33ba1
--- /dev/null
+++ b/src/ui/core/mod.rs
@@ -0,0 +1 @@
+pub mod slider;
diff --git a/src/ui/core/slider.rs b/src/ui/core/slider.rs
new file mode 100644
index 0000000..7945270
--- /dev/null
+++ b/src/ui/core/slider.rs
@@ -0,0 +1,91 @@
+use std::sync::Arc;
+
+use gpui::{
+    App, AppContext as _, DragMoveEvent, Empty, Entity, InteractiveElement as _, IntoElement,
+    ParentElement as _, Render, StatefulInteractiveElement as _, Styled as _, Window, div, px,
+    relative, rgb,
+};
+
+use crate::theme::{ACCENT_DIM, BORDER};
+
+struct SliderDrag;
+
+pub struct Slider {
+    value: f32, // 0.0..=1.0
+    on_change: Option<Arc<dyn Fn(f32, &mut App) + Send + Sync + 'static>>,
+}
+
+impl Slider {
+    pub fn new(value: f32) -> Self {
+        Self {
+            value: value.clamp(0.0, 1.0),
+            on_change: None,
+        }
+    }
+
+    pub fn on_change(mut self, f: impl Fn(f32, &mut App) + Send + Sync + 'static) -> Self {
+        self.on_change = Some(Arc::new(f));
+        self
+    }
+
+    pub fn value(&self) -> f32 {
+        self.value
+    }
+}
+
+impl Render for Slider {
+    fn render(
+        &mut self,
+        _window: &mut gpui::Window,
+        cx: &mut gpui::Context<Self>,
+    ) -> impl IntoElement {
+        let slider_entity: Entity<Slider> = cx.entity();
+
+        div()
+            .id(("slider", slider_entity.entity_id()))
+            .w_full()
+            .h(px(20.))
+            .flex()
+            .items_center()
+            .cursor_pointer()
+            .on_drag(SliderDrag, |_, _, _, cx| cx.new(|_| Empty))
+            .on_drag_move(
+                move |ev: &DragMoveEvent<SliderDrag>, _window: &mut Window, app: &mut App| {
+                    let x = ev.event.position.x;
+                    let bounds = ev.bounds;
+
+                    let width = f32::from(bounds.size.width);
+                    if width <= 0.0 {
+                        return;
+                    }
+                    let local_x = f32::from(x - bounds.left());
+                    let new_val = (local_x / width).clamp(0.0, 1.0);
+
+                    let cb = app.update_entity(&slider_entity, |slider, cx| {
+                        slider.value = new_val;
+                        cx.notify();
+                        slider.on_change.clone()
+                    });
+
+                    if let Some(cb) = cb {
+                        cb(new_val, app);
+                    }
+                },
+            )
+            .child(
+                div()
+                    .w_full()
+                    .h_2()
+                    .bg(rgb(BORDER))
+                    .rounded_full()
+                    .overflow_hidden()
+                    .child(
+                        div()
+                            .w(relative(self.value))
+                            .h_full()
+                            .bg(rgb(ACCENT_DIM))
+                            .rounded_full(),
+                    ),
+            )
+    }
+}
diff --git a/src/ui/mod.rs b/src/ui/mod.rs
index 0e4a10c..38452fa 100644
--- a/src/ui/mod.rs
+++ b/src/ui/mod.rs
@@ -1,4 +1,5 @@
 mod beat;
+pub mod core;
 mod headers;
 mod pattern;
 mod transport;
diff --git a/src/ui/transport.rs b/src/ui/transport.rs
index ff64d83..969c964 100644
--- a/src/ui/transport.rs
+++ b/src/ui/transport.rs
@@ -228,15 +228,7 @@ impl Daw {
                     .items_center()
                     .gap_2()
                     .child(dim("MASTER"))
-                    .child(
-                        div()
-                            .w_24()
-                            .h_2()
-                            .bg(rgb(BORDER))
-                            .rounded_full()
-                            .overflow_hidden()
-                            .child(div().w(px(72.)).h_full().bg(rgb(ACCENT_DIM)).rounded_full()),
-                    ),
+                    .child(div().w_24().child(self.master_slider.clone())),
             )
     }
 }