feat: playlist management, gapless playback, ReplayGain, Qobuz theme

Playlist management:
- Add/remove tracks from playlists via right-click context menu
- Create new playlists (right-click Playlists sidebar header)
- Delete playlists with confirmation dialog (right-click playlist item)
- Playlist view removes track immediately on delete (optimistic)
- Deleting currently-open playlist clears the track view

Gapless playback:
- Single long-running audio thread owns AudioOutput; CPAL stream stays
  open between tracks eliminating device teardown/startup gap
- Decode runs inline on the audio thread; command channel polled via
  try_recv() so Pause/Resume/Seek/Stop/Play all work without spawning
- New Play command arriving mid-decode is handled immediately,
  reusing the same audio output for zero-gap transition
- Position timer reduced from 500 ms to 50 ms for faster track-end detection
- URL/metadata prefetch: when gapless is enabled Qt pre-fetches the next
  track while the current one is still playing

ReplayGain:
- Toggled in Settings → Playback
- replaygain_track_gain (dB) from track audio_info converted to linear
  gain factor and applied per-sample alongside volume

Qobuz dark theme:
- Background #191919, base #141414, accent #FFB232 (yellow-orange)
- Selection highlight, slider fill, scrollbar hover all use #FFB232
- Links use Qobuz blue #46B3EE
- Hi-res H badges updated to #FFB232 (from #FFD700)
- Now-playing row uses #FFB232 (was Spotify green)
- QSS stylesheet for scrollbars, menus, inputs, buttons, groups

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

rust/include/qobuz_backend.h

@@ -31,6 +31,8 @@ enum QobuzEvent {
     EV_TRACK_URL_OK   = 17,
     EV_TRACK_URL_ERR  = 18,
     EV_GENERIC_ERR      = 19,
+    EV_PLAYLIST_CREATED = 20,
+    EV_PLAYLIST_DELETED = 21,
 };
 
 // Callback signature
@@ -69,6 +71,16 @@ uint8_t  qobuz_backend_get_volume(const QobuzBackendOpaque *backend);
 int      qobuz_backend_get_state(const QobuzBackendOpaque *backend);
 int      qobuz_backend_take_track_finished(QobuzBackendOpaque *backend);
 
+// ReplayGain / Gapless
+void qobuz_backend_set_replaygain(QobuzBackendOpaque *backend, bool enabled);
+void qobuz_backend_prefetch_track(QobuzBackendOpaque *backend, int64_t track_id, int32_t format_id);
+
+// Playlist management
+void qobuz_backend_create_playlist(QobuzBackendOpaque *backend, const char *name);
+void qobuz_backend_delete_playlist(QobuzBackendOpaque *backend, int64_t playlist_id);
+void qobuz_backend_add_track_to_playlist(QobuzBackendOpaque *backend, int64_t playlist_id, int64_t track_id);
+void qobuz_backend_delete_track_from_playlist(QobuzBackendOpaque *backend, int64_t playlist_id, int64_t playlist_track_id);
+
 // Favorites modification
 void qobuz_backend_add_fav_track(QobuzBackendOpaque *backend, int64_t track_id);
 void qobuz_backend_remove_fav_track(QobuzBackendOpaque *backend, int64_t track_id);

rust/src/api/client.rs

@@ -89,6 +89,15 @@ impl QobuzClient {
         Ok(body)
     }
 
+    fn post_request(&self, method: &str) -> reqwest::RequestBuilder {
+        let mut builder = self.http.post(self.url(method));
+        builder = builder.query(&[("app_id", self.app_id.as_str())]);
+        if let Some(token) = &self.auth_token {
+            builder = builder.header("Authorization", format!("Bearer {}", token));
+        }
+        builder
+    }
+
     fn get_request(&self, method: &str) -> reqwest::RequestBuilder {
         let mut builder = self.http.get(self.url(method));
         builder = builder.query(&[("app_id", self.app_id.as_str())]);
@@ -329,6 +338,55 @@ impl QobuzClient {
         Ok(serde_json::from_value(body["artists"].clone())?)
     }
 
+    // --- Playlist management ---
+
+    pub async fn create_playlist(&self, name: &str) -> Result<PlaylistDto> {
+        let resp = self
+            .post_request("playlist/create")
+            .form(&[("name", name), ("is_public", "false"), ("is_collaborative", "false")])
+            .send()
+            .await?;
+        let body = Self::check_response(resp).await?;
+        Ok(serde_json::from_value(body)?)
+    }
+
+    pub async fn add_track_to_playlist(&self, playlist_id: i64, track_id: i64) -> Result<()> {
+        let resp = self
+            .post_request("playlist/addTracks")
+            .form(&[
+                ("playlist_id", playlist_id.to_string()),
+                ("track_ids",   track_id.to_string()),
+                ("no_duplicate", "true".to_string()),
+            ])
+            .send()
+            .await?;
+        Self::check_response(resp).await?;
+        Ok(())
+    }
+
+    pub async fn delete_playlist(&self, playlist_id: i64) -> Result<()> {
+        let resp = self
+            .get_request("playlist/delete")
+            .query(&[("playlist_id", &playlist_id.to_string())])
+            .send()
+            .await?;
+        Self::check_response(resp).await?;
+        Ok(())
+    }
+
+    pub async fn delete_track_from_playlist(&self, playlist_id: i64, playlist_track_id: i64) -> Result<()> {
+        let resp = self
+            .post_request("playlist/deleteTracks")
+            .form(&[
+                ("playlist_id",        playlist_id.to_string()),
+                ("playlist_track_ids", playlist_track_id.to_string()),
+            ])
+            .send()
+            .await?;
+        Self::check_response(resp).await?;
+        Ok(())
+    }
+
     pub async fn add_fav_track(&self, track_id: i64) -> Result<()> {
         let resp = self
             .get_request("favorite/create")

rust/src/api/models.rs

@@ -48,6 +48,7 @@ pub struct TrackDto {
     pub title: Option<String>,
     pub duration: Option<i64>,
     pub track_number: Option<i32>,
+    pub playlist_track_id: Option<i64>,
     pub album: Option<AlbumDto>,
     pub performer: Option<ArtistDto>,
     pub composer: Option<ArtistDto>,

rust/src/lib.rs

@@ -75,12 +75,20 @@ pub type EventCallback = unsafe extern "C" fn(*mut c_void, c_int, *const c_char)
 
 // ---------- Backend ----------
 
+struct PrefetchedTrack {
+    track_id: i64,
+    track: api::models::TrackDto,
+    url: String,
+}
+
 struct BackendInner {
     client: Arc<Mutex<QobuzClient>>,
     player: Player,
     rt: Runtime,
     cb: EventCallback,
     ud: SendPtr,
+    replaygain_enabled: std::sync::Arc<std::sync::atomic::AtomicBool>,
+    prefetch: std::sync::Arc<tokio::sync::Mutex<Option<PrefetchedTrack>>>,
 }
 
 pub struct Backend(BackendInner);
@@ -121,6 +129,8 @@ pub unsafe extern "C" fn qobuz_backend_new(
         rt,
         cb: event_cb,
         ud: SendPtr(userdata),
+        replaygain_enabled: std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false)),
+        prefetch: std::sync::Arc::new(tokio::sync::Mutex::new(None)),
     })))
 }
 
@@ -341,15 +351,29 @@ pub unsafe extern "C" fn qobuz_backend_play_track(
     let format = Format::from_id(format_id);
     let cmd_tx = inner.player.cmd_tx.clone();
     let status = inner.player.status.clone();
+    let prefetch = inner.prefetch.clone();
+    let rg_enabled = inner.replaygain_enabled.clone();
 
     spawn(inner, async move {
-        // 1. Track metadata
+        // 1. Check prefetch cache first for zero-gap start
+        let cached = {
+            let mut lock = prefetch.lock().await;
+            if lock.as_ref().map(|p| p.track_id == track_id).unwrap_or(false) {
+                lock.take()
+            } else {
+                None
+            }
+        };
+
+        let (track, url) = if let Some(pf) = cached {
+            (pf.track, pf.url)
+        } else {
+            // Fetch track metadata
             let track = match client.lock().await.get_track(track_id).await {
                 Ok(t) => t,
                 Err(e) => { call_cb(cb, ud, EV_TRACK_URL_ERR, &err_json(&e.to_string())); return; }
             };
-
+            // Fetch stream URL
-        // 2. Stream URL
             let url_dto = match client.lock().await.get_track_url(track_id, format).await {
                 Ok(u) => u,
                 Err(e) => { call_cb(cb, ud, EV_TRACK_URL_ERR, &err_json(&e.to_string())); return; }
@@ -358,18 +382,27 @@ pub unsafe extern "C" fn qobuz_backend_play_track(
                 Some(u) => u,
                 None => { call_cb(cb, ud, EV_TRACK_URL_ERR, &err_json("no stream URL")); return; }
             };
+            (track, url)
+        };
 
-        // 3. Notify track change
+        // 2. Notify track change
         if let Ok(j) = serde_json::to_string(&track) {
             call_cb(cb, ud, EV_TRACK_CHANGED, &j);
         }
 
+        // 3. Compute ReplayGain if enabled
+        let replaygain_db = if rg_enabled.load(std::sync::atomic::Ordering::Relaxed) {
+            track.audio_info.as_ref().and_then(|ai| ai.replaygain_track_gain)
+        } else {
+            None
+        };
+
         // 4. Update status + send play command
         *status.current_track.lock().unwrap() = Some(track.clone());
         if let Some(dur) = track.duration {
             status.duration_secs.store(dur as u64, std::sync::atomic::Ordering::Relaxed);
         }
-        let _ = cmd_tx.send(player::PlayerCommand::Play(player::TrackInfo { track, url, format }));
+        let _ = cmd_tx.send(player::PlayerCommand::Play(player::TrackInfo { track, url, format, replaygain_db }));
 
         // 5. State notification
         call_cb(cb, ud, EV_STATE_CHANGED, r#"{"state":"playing"}"#);
@@ -438,6 +471,41 @@ pub unsafe extern "C" fn qobuz_backend_take_track_finished(ptr: *mut Backend) ->
     if finished { 1 } else { 0 }
 }
 
+// ---------- ReplayGain / Gapless ----------
+
+#[no_mangle]
+pub unsafe extern "C" fn qobuz_backend_set_replaygain(ptr: *mut Backend, enabled: bool) {
+    (*ptr).0.replaygain_enabled.store(enabled, std::sync::atomic::Ordering::Relaxed);
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn qobuz_backend_prefetch_track(
+    ptr: *mut Backend,
+    track_id: i64,
+    format_id: i32,
+) {
+    let inner  = &(*ptr).0;
+    let client = inner.client.clone();
+    let prefetch = inner.prefetch.clone();
+    let format = Format::from_id(format_id);
+
+    spawn(inner, async move {
+        let track = match client.lock().await.get_track(track_id).await {
+            Ok(t) => t,
+            Err(_) => return,
+        };
+        let url_dto = match client.lock().await.get_track_url(track_id, format).await {
+            Ok(u) => u,
+            Err(_) => return,
+        };
+        let url = match url_dto.url {
+            Some(u) => u,
+            None => return,
+        };
+        *prefetch.lock().await = Some(PrefetchedTrack { track_id, track, url });
+    });
+}
+
 // ---------- Favorites modification ----------
 
 #[no_mangle]
@@ -489,3 +557,68 @@ pub unsafe extern "C" fn qobuz_backend_remove_fav_album(ptr: *mut Backend, album
         }
     });
 }
+
+// ---------- Playlist management ----------
+
+pub const EV_PLAYLIST_CREATED: c_int = 20;
+pub const EV_PLAYLIST_DELETED: c_int = 21;
+
+#[no_mangle]
+pub unsafe extern "C" fn qobuz_backend_create_playlist(ptr: *mut Backend, name: *const c_char) {
+    let inner = &(*ptr).0;
+    let name  = CStr::from_ptr(name).to_string_lossy().into_owned();
+    let client = inner.client.clone();
+    let cb = inner.cb; let ud = inner.ud;
+    spawn(inner, async move {
+        match client.lock().await.create_playlist(&name).await {
+            Ok(p)  => call_cb(cb, ud, EV_PLAYLIST_CREATED, &serde_json::to_string(&p).unwrap_or_default()),
+            Err(e) => call_cb(cb, ud, EV_GENERIC_ERR, &err_json(&e.to_string())),
+        }
+    });
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn qobuz_backend_delete_playlist(ptr: *mut Backend, playlist_id: i64) {
+    let inner  = &(*ptr).0;
+    let client = inner.client.clone();
+    let cb = inner.cb; let ud = inner.ud;
+    spawn(inner, async move {
+        match client.lock().await.delete_playlist(playlist_id).await {
+            Ok(()) => call_cb(cb, ud, EV_PLAYLIST_DELETED,
+                &serde_json::json!({"playlist_id": playlist_id}).to_string()),
+            Err(e) => call_cb(cb, ud, EV_GENERIC_ERR, &err_json(&e.to_string())),
+        }
+    });
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn qobuz_backend_add_track_to_playlist(
+    ptr: *mut Backend,
+    playlist_id: i64,
+    track_id: i64,
+) {
+    let inner  = &(*ptr).0;
+    let client = inner.client.clone();
+    let cb = inner.cb; let ud = inner.ud;
+    spawn(inner, async move {
+        if let Err(e) = client.lock().await.add_track_to_playlist(playlist_id, track_id).await {
+            call_cb(cb, ud, EV_GENERIC_ERR, &err_json(&e.to_string()));
+        }
+    });
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn qobuz_backend_delete_track_from_playlist(
+    ptr: *mut Backend,
+    playlist_id: i64,
+    playlist_track_id: i64,
+) {
+    let inner  = &(*ptr).0;
+    let client = inner.client.clone();
+    let cb = inner.cb; let ud = inner.ud;
+    spawn(inner, async move {
+        if let Err(e) = client.lock().await.delete_track_from_playlist(playlist_id, playlist_track_id).await {
+            call_cb(cb, ud, EV_GENERIC_ERR, &err_json(&e.to_string()));
+        }
+    });
+}

rust/src/player/decoder.rs

@@ -15,7 +15,7 @@ use symphonia::core::{
     units::Time,
 };
 
-use crate::player::{output::AudioOutput, PlayerStatus};
+use super::{output::AudioOutput, PlayerCommand, PlayerStatus, TrackInfo};
 
 /// First 512 KiB of stream kept in memory to support backward seeks during probing.
 const HEAD_SIZE: usize = 512 * 1024;
@@ -127,13 +127,22 @@ impl MediaSource for HttpStreamSource {
     }
 }
 
-/// Stream and decode audio from `url`. Runs on a dedicated OS thread.
+/// Decode and play `url` inline on the calling thread (the player loop).
-pub fn play_track(
+///
+/// `audio_output` is reused across calls if the sample rate and channel count match,
+/// keeping the CPAL stream open between tracks for gapless playback.
+///
+/// Returns:
+/// - `Ok(Some(TrackInfo))` — a new Play command arrived; start that track next.
+/// - `Ok(None)`            — track finished naturally or was stopped.
+/// - `Err(_)`              — unrecoverable playback error.
+pub fn play_track_inline(
     url: &str,
     status: &PlayerStatus,
-    stop: &Arc<AtomicBool>,
     paused: &Arc<AtomicBool>,
-) -> Result<()> {
+    audio_output: &mut Option<AudioOutput>,
+    cmd_rx: &std::sync::mpsc::Receiver<PlayerCommand>,
+) -> Result<Option<TrackInfo>> {
     let response = reqwest::blocking::get(url)?;
     let content_length = response.content_length();
     let source = HttpStreamSource::new(response, content_length);
@@ -160,19 +169,91 @@ pub fn play_track(
         .make(&track.codec_params, &DecoderOptions::default())
         .map_err(|e| anyhow::anyhow!("decoder init failed: {e}"))?;
 
-    let mut audio_output = AudioOutput::try_open(sample_rate, channels)?;
+    // Reuse existing audio output if format matches; rebuild only on format change.
+    if let Some(ao) = audio_output.as_ref() {
+        if ao.sample_rate != sample_rate || ao.channels != channels {
+            *audio_output = None; // will be recreated below
+        }
+    }
+    if audio_output.is_none() {
+        *audio_output = Some(AudioOutput::try_open(sample_rate, channels)?);
+    }
+    let ao = audio_output.as_mut().unwrap();
 
+    let mut stopped = false;
+    let mut next_track: Option<TrackInfo> = None;
+
+    'decode: loop {
+        // Non-blocking command check — handle Pause/Resume/Seek/Stop/Play
         loop {
-        if stop.load(Ordering::SeqCst) {
+            match cmd_rx.try_recv() {
+                Ok(PlayerCommand::Pause) => {
+                    paused.store(true, Ordering::SeqCst);
+                    *status.state.lock().unwrap() = super::PlayerState::Paused;
+                }
+                Ok(PlayerCommand::Resume) => {
+                    paused.store(false, Ordering::SeqCst);
+                    *status.state.lock().unwrap() = super::PlayerState::Playing;
+                }
+                Ok(PlayerCommand::Seek(s)) => {
+                    status.seek_target_secs.store(s, Ordering::Relaxed);
+                    status.seek_requested.load(Ordering::SeqCst); // read-side fence
+                    status.seek_requested.store(true, Ordering::SeqCst);
+                }
+                Ok(PlayerCommand::SetVolume(v)) => {
+                    status.volume.store(v, Ordering::Relaxed);
+                }
+                Ok(PlayerCommand::Stop) => {
+                    paused.store(false, Ordering::SeqCst);
+                    *status.state.lock().unwrap() = super::PlayerState::Idle;
+                    *status.current_track.lock().unwrap() = None;
+                    status.position_secs.store(0, Ordering::Relaxed);
+                    status.duration_secs.store(0, Ordering::Relaxed);
+                    stopped = true;
+                    break 'decode;
+                }
+                Ok(PlayerCommand::Play(info)) => {
+                    // New track requested — stop current and return it
+                    next_track = Some(info);
+                    break 'decode;
+                }
+                Err(std::sync::mpsc::TryRecvError::Empty) => break,
+                Err(std::sync::mpsc::TryRecvError::Disconnected) => {
+                    stopped = true;
+                    break 'decode;
+                }
+            }
+        }
+
+        // Spin while paused, but keep checking for commands
+        while paused.load(Ordering::SeqCst) {
+            std::thread::sleep(std::time::Duration::from_millis(10));
+            // Still check for Stop/Play while paused
+            match cmd_rx.try_recv() {
+                Ok(PlayerCommand::Resume) => {
+                    paused.store(false, Ordering::SeqCst);
+                    *status.state.lock().unwrap() = super::PlayerState::Playing;
+                }
+                Ok(PlayerCommand::Stop) => {
+                    paused.store(false, Ordering::SeqCst);
+                    stopped = true;
                     break;
                 }
-        while paused.load(Ordering::SeqCst) {
+                Ok(PlayerCommand::Play(info)) => {
-            std::thread::sleep(std::time::Duration::from_millis(50));
+                    paused.store(false, Ordering::SeqCst);
-            if stop.load(Ordering::SeqCst) {
+                    next_track = Some(info);
-                return Ok(());
+                    break 'decode;
                 }
+                Ok(PlayerCommand::SetVolume(v)) => {
+                    status.volume.store(v, Ordering::Relaxed);
                 }
+                _ => {}
+            }
+            if stopped { break 'decode; }
+        }
+        if stopped { break; }
 
+        // Handle seek
         if status.seek_requested.load(Ordering::SeqCst) {
             status.seek_requested.store(false, Ordering::SeqCst);
             let target = status.seek_target_secs.load(Ordering::Relaxed);
@@ -190,8 +271,10 @@ pub fn play_track(
 
         let packet = match format.next_packet() {
             Ok(p) => p,
-            Err(SymphoniaError::IoError(e)) if e.kind() == std::io::ErrorKind::UnexpectedEof => {
+            Err(SymphoniaError::IoError(e))
-                break;
+                if e.kind() == std::io::ErrorKind::UnexpectedEof =>
+            {
+                break; // natural end of track
             }
             Err(SymphoniaError::ResetRequired) => {
                 decoder.reset();
@@ -205,13 +288,16 @@ pub fn play_track(
         }
 
         if let Some(ts) = packet.ts().checked_div(sample_rate as u64) {
-            status.position_secs.store(ts, std::sync::atomic::Ordering::Relaxed);
+            status.position_secs.store(ts, Ordering::Relaxed);
         }
 
         match decoder.decode(&packet) {
             Ok(decoded) => {
                 let volume = status.volume.load(Ordering::Relaxed) as f32 / 100.0;
-                audio_output.write(decoded, volume, stop)?;
+                let rg = *status.replaygain_gain.lock().unwrap();
+                // Use a stop flag tied to new-track-incoming so write doesn't block
+                let dummy_stop = Arc::new(AtomicBool::new(false));
+                ao.write(decoded, (volume * rg).min(1.0), &dummy_stop)?;
             }
             Err(SymphoniaError::IoError(_)) => break,
             Err(SymphoniaError::DecodeError(e)) => eprintln!("decode error: {e}"),
@@ -219,5 +305,10 @@ pub fn play_track(
         }
     }
 
-    Ok(())
+    if stopped {
+        // On explicit stop, drop the audio output to silence immediately
+        *audio_output = None;
+    }
+
+    Ok(next_track)
 }

rust/src/player/mod.rs

@@ -24,6 +24,8 @@ pub struct TrackInfo {
     pub track: TrackDto,
     pub url: String,
     pub format: Format,
+    /// ReplayGain track gain in dB, if enabled and available.
+    pub replaygain_db: Option<f64>,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -47,6 +49,8 @@ pub struct PlayerStatus {
     /// Set by the player loop when a seek command arrives; cleared by the decode thread.
     pub seek_requested: Arc<AtomicBool>,
     pub seek_target_secs: Arc<AtomicU64>,
+    /// Linear gain factor to apply (1.0 = unity). Updated each time a new track starts.
+    pub replaygain_gain: Arc<std::sync::Mutex<f32>>,
 }
 
 impl PlayerStatus {
@@ -60,6 +64,7 @@ impl PlayerStatus {
             track_finished: Arc::new(AtomicBool::new(false)),
             seek_requested: Arc::new(AtomicBool::new(false)),
             seek_target_secs: Arc::new(AtomicU64::new(0)),
+            replaygain_gain: Arc::new(std::sync::Mutex::new(1.0)),
         }
     }
 
@@ -106,10 +111,6 @@ impl Player {
         self.cmd_tx.send(cmd).ok();
     }
 
-    pub fn play_track(&self, track: TrackDto, url: String, format: Format) {
-        self.send(PlayerCommand::Play(TrackInfo { track, url, format }));
-    }
-
     pub fn pause(&self) {
         self.send(PlayerCommand::Pause);
     }
@@ -133,17 +134,54 @@ impl Player {
     }
 }
 
+/// The player loop runs on a single dedicated OS thread.
+/// It owns the `AudioOutput` locally so there are no Send constraints.
+/// Decoding is performed inline; the command channel is polled via try_recv
+/// inside the decode loop to handle Pause/Resume/Seek/Stop/Play without
+/// tearng down and re-opening the audio device between tracks.
 fn player_loop(rx: std::sync::mpsc::Receiver<PlayerCommand>, status: PlayerStatus) {
-    let mut stop_flag = Arc::new(AtomicBool::new(true));
+    use std::sync::mpsc::RecvTimeoutError;
-    let paused = Arc::new(AtomicBool::new(false));
 
+    let mut audio_output: Option<output::AudioOutput> = None;
+    let paused = Arc::new(AtomicBool::new(false));
+    // pending_info holds a Play command that interrupted an ongoing decode
+    let mut pending_info: Option<TrackInfo> = None;
+
+    'outer: loop {
+        // Wait for a Play command (or use one that was interrupted)
+        let info = if let Some(p) = pending_info.take() {
+            p
+        } else {
             loop {
                 match rx.recv_timeout(Duration::from_millis(100)) {
-            Ok(cmd) => match cmd {
+                    Ok(PlayerCommand::Play(info)) => break info,
-                PlayerCommand::Play(info) => {
+                    Ok(PlayerCommand::Stop) => {
-                    stop_flag.store(true, Ordering::SeqCst);
+                        audio_output = None;
-                    stop_flag = Arc::new(AtomicBool::new(false));
                         paused.store(false, Ordering::SeqCst);
+                        *status.state.lock().unwrap() = PlayerState::Idle;
+                        *status.current_track.lock().unwrap() = None;
+                        status.position_secs.store(0, Ordering::Relaxed);
+                        status.duration_secs.store(0, Ordering::Relaxed);
+                    }
+                    Ok(PlayerCommand::SetVolume(v)) => {
+                        status.volume.store(v, Ordering::Relaxed);
+                    }
+                    Ok(PlayerCommand::Seek(s)) => {
+                        status.seek_target_secs.store(s, Ordering::Relaxed);
+                        status.seek_requested.store(true, Ordering::SeqCst);
+                    }
+                    Ok(_) => {} // Pause/Resume ignored when idle
+                    Err(RecvTimeoutError::Timeout) => {}
+                    Err(RecvTimeoutError::Disconnected) => break 'outer,
+                }
+            }
+        };
+
+        // Compute ReplayGain factor
+        let rg_factor = info.replaygain_db
+            .map(|db| 10f32.powf(db as f32 / 20.0))
+            .unwrap_or(1.0);
+        *status.replaygain_gain.lock().unwrap() = rg_factor;
 
         *status.state.lock().unwrap() = PlayerState::Playing;
         *status.current_track.lock().unwrap() = Some(info.track.clone());
@@ -151,50 +189,22 @@ fn player_loop(rx: std::sync::mpsc::Receiver<PlayerCommand>, status: PlayerStatu
             status.duration_secs.store(dur as u64, Ordering::Relaxed);
         }
         status.position_secs.store(0, Ordering::Relaxed);
+        paused.store(false, Ordering::SeqCst);
 
-                    let status_c = status.clone();
+        match decoder::play_track_inline(&info.url, &status, &paused, &mut audio_output, &rx) {
-                    let stop_c = stop_flag.clone();
+            Ok(Some(next_info)) => {
-                    let paused_c = paused.clone();
+                // Interrupted by a new Play — loop immediately with reused audio output
-
+                pending_info = Some(next_info);
-                    std::thread::spawn(move || {
-                        match decoder::play_track(&info.url, &status_c, &stop_c, &paused_c) {
-                            Ok(()) => {
-                                if !stop_c.load(Ordering::SeqCst) {
-                                    *status_c.state.lock().unwrap() = PlayerState::Idle;
-                                    status_c.track_finished.store(true, Ordering::SeqCst);
             }
+            Ok(None) => {
+                // Track finished naturally
+                *status.state.lock().unwrap() = PlayerState::Idle;
+                status.track_finished.store(true, Ordering::SeqCst);
             }
             Err(e) => {
                 eprintln!("playback error: {e}");
-                                *status_c.state.lock().unwrap() =
+                *status.state.lock().unwrap() = PlayerState::Error(e.to_string());
-                                    PlayerState::Error(e.to_string());
             }
         }
-                    });
-                }
-                PlayerCommand::Pause => {
-                    paused.store(true, Ordering::SeqCst);
-                    *status.state.lock().unwrap() = PlayerState::Paused;
-                }
-                PlayerCommand::Resume => {
-                    paused.store(false, Ordering::SeqCst);
-                    *status.state.lock().unwrap() = PlayerState::Playing;
-                }
-                PlayerCommand::Stop => {
-                    stop_flag.store(true, Ordering::SeqCst);
-                    *status.state.lock().unwrap() = PlayerState::Idle;
-                    *status.current_track.lock().unwrap() = None;
-                    status.position_secs.store(0, Ordering::Relaxed);
-                    status.duration_secs.store(0, Ordering::Relaxed);
-                }
-                PlayerCommand::SetVolume(_) => {}
-                PlayerCommand::Seek(secs) => {
-                    status.seek_target_secs.store(secs, Ordering::Relaxed);
-                    status.seek_requested.store(true, Ordering::SeqCst);
-                }
-            },
-            Err(std::sync::mpsc::RecvTimeoutError::Timeout) => {}
-            Err(std::sync::mpsc::RecvTimeoutError::Disconnected) => break,
-        }
     }
 }

rust/src/player/output.rs

@@ -15,6 +15,8 @@ const RING_BUFFER_SIZE: usize = 32 * 1024;
 pub struct AudioOutput {
     ring_buf_producer: rb::Producer<f32>,
     _stream: cpal::Stream,
+    pub sample_rate: u32,
+    pub channels: usize,
 }
 
 impl AudioOutput {
@@ -50,6 +52,8 @@ impl AudioOutput {
         Ok(Self {
             ring_buf_producer: producer,
             _stream: stream,
+            sample_rate,
+            channels,
         })
     }
 

src/backend/qobuzbackend.cpp

@@ -10,7 +10,7 @@ QobuzBackend::QobuzBackend(QObject *parent)
     m_backend = qobuz_backend_new(&QobuzBackend::eventTrampoline, this);
 
     m_positionTimer = new QTimer(this);
-    m_positionTimer->setInterval(500);
+    m_positionTimer->setInterval(50);
     connect(m_positionTimer, &QTimer::timeout, this, &QobuzBackend::onPositionTick);
     m_positionTimer->start();
 }
@@ -79,6 +79,40 @@ void QobuzBackend::getUserPlaylists(quint32 offset, quint32 limit)
     qobuz_backend_get_user_playlists(m_backend, offset, limit);
 }
 
+// ---- playback options ----
+
+void QobuzBackend::setReplayGain(bool enabled)
+{
+    qobuz_backend_set_replaygain(m_backend, enabled);
+}
+
+void QobuzBackend::prefetchTrack(qint64 trackId, int formatId)
+{
+    qobuz_backend_prefetch_track(m_backend, trackId, formatId);
+}
+
+// ---- playlist management ----
+
+void QobuzBackend::createPlaylist(const QString &name)
+{
+    qobuz_backend_create_playlist(m_backend, name.toUtf8().constData());
+}
+
+void QobuzBackend::deletePlaylist(qint64 playlistId)
+{
+    qobuz_backend_delete_playlist(m_backend, playlistId);
+}
+
+void QobuzBackend::addTrackToPlaylist(qint64 playlistId, qint64 trackId)
+{
+    qobuz_backend_add_track_to_playlist(m_backend, playlistId, trackId);
+}
+
+void QobuzBackend::deleteTrackFromPlaylist(qint64 playlistId, qint64 playlistTrackId)
+{
+    qobuz_backend_delete_track_from_playlist(m_backend, playlistId, playlistTrackId);
+}
+
 // ---- fav modification ----
 
 void QobuzBackend::addFavTrack(qint64 trackId)
@@ -201,6 +235,12 @@ void QobuzBackend::onEvent(int eventType, const QString &json)
     case EV_STATE_CHANGED:
         emit stateChanged(obj["state"].toString());
         break;
+    case 20: // EV_PLAYLIST_CREATED
+        emit playlistCreated(obj);
+        break;
+    case 21: // EV_PLAYLIST_DELETED
+        emit playlistDeleted(obj);
+        break;
     case EV_GENERIC_ERR:
     case EV_TRACK_URL_ERR:
         emit error(obj["error"].toString());

src/backend/qobuzbackend.hpp

@@ -36,6 +36,16 @@ public:
     void getFavArtists(quint32 offset = 0, quint32 limit = 200);
     void getUserPlaylists(quint32 offset = 0, quint32 limit = 200);
 
+    // --- playback options ---
+    void setReplayGain(bool enabled);
+    void prefetchTrack(qint64 trackId, int formatId = 6);
+
+    // --- playlist management ---
+    void createPlaylist(const QString &name);
+    void deletePlaylist(qint64 playlistId);
+    void addTrackToPlaylist(qint64 playlistId, qint64 trackId);
+    void deleteTrackFromPlaylist(qint64 playlistId, qint64 playlistTrackId);
+
     // --- fav modification ---
     void addFavTrack(qint64 trackId);
     void removeFavTrack(qint64 trackId);
@@ -66,6 +76,8 @@ signals:
     void albumLoaded(const QJsonObject &album);
     void artistLoaded(const QJsonObject &artist);
     void playlistLoaded(const QJsonObject &playlist);
+    void playlistCreated(const QJsonObject &playlist);
+    void playlistDeleted(const QJsonObject &result);
 
     // favorites
     void favTracksLoaded(const QJsonObject &result);

src/dialog/settings.cpp

@@ -36,6 +36,15 @@ SettingsDialog::SettingsDialog(QWidget *parent) : QDialog(parent)
         }
     }
     playLayout->addRow(tr("Preferred quality:"), m_formatBox);
+
+    m_replayGain = new QCheckBox(tr("Enable ReplayGain (track gain normalisation)"), playGroup);
+    m_replayGain->setChecked(AppSettings::instance().replayGainEnabled());
+    playLayout->addRow(m_replayGain);
+
+    m_gapless = new QCheckBox(tr("Gapless playback (pre-fetch next track)"), playGroup);
+    m_gapless->setChecked(AppSettings::instance().gaplessEnabled());
+    playLayout->addRow(m_gapless);
+
     layout->addWidget(playGroup);
 
     // --- Last.fm group ---
@@ -90,6 +99,8 @@ SettingsDialog::SettingsDialog(QWidget *parent) : QDialog(parent)
 void SettingsDialog::applyChanges()
 {
     AppSettings::instance().setPreferredFormat(m_formatBox->currentData().toInt());
+    AppSettings::instance().setReplayGainEnabled(m_replayGain->isChecked());
+    AppSettings::instance().setGaplessEnabled(m_gapless->isChecked());
     AppSettings::instance().setLastFmEnabled(m_lastFmEnabled->isChecked());
     AppSettings::instance().setLastFmApiKey(m_lastFmApiKey->text().trimmed());
     AppSettings::instance().setLastFmApiSecret(m_lastFmApiSecret->text().trimmed());

src/dialog/settings.hpp

@@ -18,6 +18,8 @@ public:
 private:
     // Playback
     QComboBox *m_formatBox      = nullptr;
+    QCheckBox *m_replayGain     = nullptr;
+    QCheckBox *m_gapless        = nullptr;
 
     // Last.fm
     QCheckBox  *m_lastFmEnabled    = nullptr;

src/list/library.cpp

@@ -3,6 +3,9 @@
 #include <QHeaderView>
 #include <QJsonArray>
 #include <QJsonObject>
+#include <QInputDialog>
+#include <QMenu>
+#include <QMessageBox>
 
 namespace List
 {
@@ -24,16 +27,29 @@ Library::Library(QobuzBackend *backend, QWidget *parent)
 {
     setHeaderHidden(true);
     setRootIsDecorated(true);
-    setContextMenuPolicy(Qt::NoContextMenu);
+    setContextMenuPolicy(Qt::CustomContextMenu);
 
     buildStaticNodes();
 
     connect(m_backend, &QobuzBackend::userPlaylistsLoaded,
             this, &Library::onUserPlaylistsLoaded);
+    connect(m_backend, &QobuzBackend::playlistCreated,
+            this, [this](const QJsonObject &) { refresh(); });
+    connect(m_backend, &QobuzBackend::playlistDeleted,
+            this, [this](const QJsonObject &result) {
+        const qint64 deletedId = static_cast<qint64>(result["playlist_id"].toDouble());
+        if (deletedId == m_openPlaylistId) {
+            m_openPlaylistId = 0;
+            emit openPlaylistDeleted();
+        }
+        refresh();
+    });
     connect(this, &QTreeWidget::itemClicked,
             this, &Library::onItemClicked);
     connect(this, &QTreeWidget::itemDoubleClicked,
             this, &Library::onItemDoubleClicked);
+    connect(this, &QTreeWidget::customContextMenuRequested,
+            this, &Library::onContextMenuRequested);
 }
 
 void Library::buildStaticNodes()
@@ -70,6 +86,7 @@ void Library::onUserPlaylistsLoaded(const QJsonObject &result)
     while (m_playlistsNode->childCount() > 0)
         delete m_playlistsNode->takeChild(0);
 
+    QVector<QPair<qint64, QString>> playlists;
     const QJsonArray items = result["items"].toArray();
     for (const auto &v : items) {
         const QJsonObject pl = v.toObject();
@@ -80,7 +97,55 @@ void Library::onUserPlaylistsLoaded(const QJsonObject &result)
         item->setData(0, TypeRole, NodePlaylist);
         item->setData(0, IdRole,   id);
         item->setData(0, NameRole, name);
+
+        playlists.append({id, name});
     }
+
+    emit userPlaylistsChanged(playlists);
+}
+
+void Library::onContextMenuRequested(const QPoint &pos)
+{
+    QTreeWidgetItem *item = itemAt(pos);
+    if (!item) return;
+
+    const bool isHeader = (item == m_playlistsNode);
+    const bool isPlaylistItem = (!isHeader && item->parent() == m_playlistsNode &&
+                                  item->data(0, TypeRole).toInt() == NodePlaylist);
+
+    if (!isHeader && !isPlaylistItem) return;
+
+    QMenu menu(this);
+
+    auto *newPl = menu.addAction(tr("New Playlist…"));
+    connect(newPl, &QAction::triggered, this, [this] {
+        bool ok = false;
+        const QString name = QInputDialog::getText(
+            this, tr("New Playlist"), tr("Playlist name:"),
+            QLineEdit::Normal, QString(), &ok);
+        if (ok && !name.trimmed().isEmpty())
+            m_backend->createPlaylist(name.trimmed());
+    });
+
+    if (isPlaylistItem) {
+        const qint64  plId   = item->data(0, IdRole).toLongLong();
+        const QString plName = item->data(0, NameRole).toString();
+
+        menu.addSeparator();
+        auto *delPl = menu.addAction(tr("Delete \"%1\"…").arg(plName));
+        connect(delPl, &QAction::triggered, this, [this, plId, plName] {
+            const auto answer = QMessageBox::question(
+                this,
+                tr("Delete Playlist"),
+                tr("Permanently delete \"%1\"? This cannot be undone.").arg(plName),
+                QMessageBox::Yes | QMessageBox::Cancel,
+                QMessageBox::Cancel);
+            if (answer == QMessageBox::Yes)
+                m_backend->deletePlaylist(plId);
+        });
+    }
+
+    menu.exec(viewport()->mapToGlobal(pos));
 }
 
 void Library::onItemClicked(QTreeWidgetItem *item, int)
@@ -95,6 +160,7 @@ void Library::onItemClicked(QTreeWidgetItem *item, int)
     case NodePlaylist: {
         const qint64  id   = item->data(0, IdRole).toLongLong();
         const QString name = item->data(0, NameRole).toString();
+        m_openPlaylistId = id;
         emit playlistRequested(id, name);
         break;
     }

src/list/library.hpp

@@ -3,6 +3,9 @@
 #include "../backend/qobuzbackend.hpp"
 
 #include <QTreeWidget>
+#include <QVector>
+#include <QPair>
+#include <QString>
 
 namespace List
 {
@@ -23,17 +26,23 @@ namespace List
         void favAlbumsRequested();
         void favArtistsRequested();
         void playlistRequested(qint64 playlistId, const QString &name);
+        /// Emitted after playlists are loaded so others can cache the list.
+        void userPlaylistsChanged(const QVector<QPair<qint64, QString>> &playlists);
+        /// Emitted when the currently open playlist was deleted.
+        void openPlaylistDeleted();
 
     private slots:
         void onUserPlaylistsLoaded(const QJsonObject &result);
         void onItemClicked(QTreeWidgetItem *item, int column);
         void onItemDoubleClicked(QTreeWidgetItem *item, int column);
+        void onContextMenuRequested(const QPoint &pos);
 
     private:
         QobuzBackend *m_backend = nullptr;
 
         QTreeWidgetItem *m_myLibNode     = nullptr;
         QTreeWidgetItem *m_playlistsNode = nullptr;
+        qint64           m_openPlaylistId = 0;
 
         void buildStaticNodes();
     };

src/list/tracks.cpp

@@ -39,26 +39,41 @@ Tracks::Tracks(QobuzBackend *backend, PlayQueue *queue, QWidget *parent)
 
 void Tracks::loadTracks(const QJsonArray &tracks)
 {
+    setPlaylistContext(0);
     m_model->setTracks(tracks, false, /*useSequential=*/true);
 }
 
 void Tracks::loadAlbum(const QJsonObject &album)
 {
+    setPlaylistContext(0);
     const QJsonArray items = album["tracks"].toObject()["items"].toArray();
     m_model->setTracks(items); // album: use track_number
 }
 
 void Tracks::loadPlaylist(const QJsonObject &playlist)
 {
+    const qint64 id = static_cast<qint64>(playlist["id"].toDouble());
+    setPlaylistContext(id);
     const QJsonArray items = playlist["tracks"].toObject()["items"].toArray();
     m_model->setTracks(items, /*usePosition=*/true);
 }
 
 void Tracks::loadSearchTracks(const QJsonArray &tracks)
 {
+    setPlaylistContext(0);
     m_model->setTracks(tracks, false, /*useSequential=*/true);
 }
 
+void Tracks::setPlaylistContext(qint64 playlistId)
+{
+    m_playlistId = playlistId;
+}
+
+void Tracks::setUserPlaylists(const QVector<QPair<qint64, QString>> &playlists)
+{
+    m_userPlaylists = playlists;
+}
+
 void Tracks::setPlayingTrackId(qint64 id)
 {
     m_model->setPlayingId(id);
@@ -134,6 +149,36 @@ void Tracks::onContextMenu(const QPoint &pos)
         });
     }
 
+    // Playlist management
+    if (!m_userPlaylists.isEmpty()) {
+        menu.addSeparator();
+        auto *addToPlMenu = menu.addMenu(
+            QIcon(":/res/icons/media-playlist-append.svg"), tr("Add to playlist"));
+        for (const auto &pl : m_userPlaylists) {
+            const qint64  plId   = pl.first;
+            const QString plName = pl.second;
+            auto *act = addToPlMenu->addAction(plName);
+            connect(act, &QAction::triggered, this, [this, id, plId] {
+                emit addToPlaylistRequested(id, plId);
+            });
+        }
+    }
+
+    if (m_playlistId > 0) {
+        const qint64 playlistTrackId =
+            m_model->data(index, TrackListModel::PlaylistTrackIdRole).toLongLong();
+        if (playlistTrackId > 0) {
+            if (m_userPlaylists.isEmpty()) menu.addSeparator();
+            auto *remFromPl = menu.addAction(tr("Remove from this playlist"));
+            const qint64 curPlaylistId = m_playlistId;
+            const int    curRow        = index.row();
+            connect(remFromPl, &QAction::triggered, this, [this, curPlaylistId, playlistTrackId, curRow] {
+                emit removeFromPlaylistRequested(curPlaylistId, playlistTrackId);
+                m_model->removeTrack(curRow);  // optimistic: remove immediately from view
+            });
+        }
+    }
+
     menu.exec(viewport()->mapToGlobal(pos));
 }
 

src/list/tracks.hpp

@@ -7,6 +7,9 @@
 #include <QTreeView>
 #include <QJsonArray>
 #include <QJsonObject>
+#include <QVector>
+#include <QPair>
+#include <QString>
 
 namespace List
 {
@@ -25,13 +28,22 @@ namespace List
         /// Called when the backend fires EV_TRACK_CHANGED so the playing row is highlighted.
         void setPlayingTrackId(qint64 id);
 
+        /// Set which playlist is currently displayed (0 = none).
+        void setPlaylistContext(qint64 playlistId);
+        /// Provide the user's playlist list for the "Add to playlist" submenu.
+        void setUserPlaylists(const QVector<QPair<qint64, QString>> &playlists);
+
     signals:
         void playTrackRequested(qint64 trackId);
+        void addToPlaylistRequested(qint64 trackId, qint64 playlistId);
+        void removeFromPlaylistRequested(qint64 playlistId, qint64 playlistTrackId);
 
     private:
         TrackListModel *m_model   = nullptr;
         QobuzBackend   *m_backend = nullptr;
         PlayQueue      *m_queue   = nullptr;
+        qint64          m_playlistId = 0;
+        QVector<QPair<qint64, QString>> m_userPlaylists;
 
         void onDoubleClicked(const QModelIndex &index);
         void onContextMenu(const QPoint &pos);

src/main.cpp

@@ -11,27 +11,67 @@ int main(int argc, char *argv[])
     app.setOrganizationName(QStringLiteral("qobuz-qt"));
     app.setApplicationVersion(QStringLiteral("0.1.0"));
 
-    // Dark palette consistent with spotify-qt style
+    // Qobuz dark palette
+    // Accent: #FFB232 (yellow-orange), Blue: #46B3EE, Backgrounds: #191919 / #141414
     app.setStyle(QStyleFactory::create(QStringLiteral("Fusion")));
     QPalette darkPalette;
-    darkPalette.setColor(QPalette::Window,          QColor(35, 35, 35));
+    darkPalette.setColor(QPalette::Window,          QColor(0x19, 0x19, 0x19));
-    darkPalette.setColor(QPalette::WindowText,      Qt::white);
+    darkPalette.setColor(QPalette::WindowText,      QColor(0xe8, 0xe8, 0xe8));
-    darkPalette.setColor(QPalette::Base,            QColor(25, 25, 25));
+    darkPalette.setColor(QPalette::Base,            QColor(0x14, 0x14, 0x14));
-    darkPalette.setColor(QPalette::AlternateBase,   QColor(45, 45, 45));
+    darkPalette.setColor(QPalette::AlternateBase,   QColor(0x1e, 0x1e, 0x1e));
-    darkPalette.setColor(QPalette::ToolTipBase,     Qt::white);
+    darkPalette.setColor(QPalette::ToolTipBase,     QColor(0x19, 0x19, 0x19));
-    darkPalette.setColor(QPalette::ToolTipText,     Qt::white);
+    darkPalette.setColor(QPalette::ToolTipText,     QColor(0xe8, 0xe8, 0xe8));
-    darkPalette.setColor(QPalette::Text,            Qt::white);
+    darkPalette.setColor(QPalette::Text,            QColor(0xe8, 0xe8, 0xe8));
-    darkPalette.setColor(QPalette::Button,          QColor(53, 53, 53));
+    darkPalette.setColor(QPalette::Button,          QColor(0x2a, 0x2a, 0x2a));
-    darkPalette.setColor(QPalette::ButtonText,      Qt::white);
+    darkPalette.setColor(QPalette::ButtonText,      QColor(0xe8, 0xe8, 0xe8));
-    darkPalette.setColor(QPalette::BrightText,      Qt::red);
+    darkPalette.setColor(QPalette::BrightText,      QColor(0xFF, 0xB2, 0x32));
-    darkPalette.setColor(QPalette::Link,            QColor(42, 130, 218));
+    darkPalette.setColor(QPalette::Link,            QColor(0x46, 0xB3, 0xEE)); // Qobuz blue
-    darkPalette.setColor(QPalette::Highlight,       QColor(42, 130, 218));
+    darkPalette.setColor(QPalette::Highlight,       QColor(0xFF, 0xB2, 0x32)); // Qobuz orange
-    darkPalette.setColor(QPalette::HighlightedText, Qt::black);
+    darkPalette.setColor(QPalette::HighlightedText, QColor(0x10, 0x10, 0x10)); // dark on orange
-    darkPalette.setColor(QPalette::PlaceholderText,                QColor(140, 140, 140));
+    darkPalette.setColor(QPalette::PlaceholderText,                QColor(0x66, 0x66, 0x66));
-    darkPalette.setColor(QPalette::Disabled, QPalette::Text,       QColor(127, 127, 127));
+    darkPalette.setColor(QPalette::Disabled, QPalette::Text,       QColor(0x55, 0x55, 0x55));
-    darkPalette.setColor(QPalette::Disabled, QPalette::ButtonText, QColor(127, 127, 127));
+    darkPalette.setColor(QPalette::Disabled, QPalette::ButtonText, QColor(0x55, 0x55, 0x55));
+    darkPalette.setColor(QPalette::Mid,             QColor(0x2f, 0x2f, 0x2f));
+    darkPalette.setColor(QPalette::Dark,            QColor(0x0e, 0x0e, 0x0e));
     app.setPalette(darkPalette);
 
+    // Stylesheet tweaks: orange accent on scrollbars, focus rings, etc.
+    app.setStyleSheet(QStringLiteral(
+        "QScrollBar:vertical { width: 6px; background: #141414; border: none; }"
+        "QScrollBar::handle:vertical { background: #3a3a3a; border-radius: 3px; min-height: 20px; }"
+        "QScrollBar::handle:vertical:hover { background: #FFB232; }"
+        "QScrollBar::add-line:vertical, QScrollBar::sub-line:vertical { height: 0; }"
+        "QScrollBar:horizontal { height: 6px; background: #141414; border: none; }"
+        "QScrollBar::handle:horizontal { background: #3a3a3a; border-radius: 3px; min-width: 20px; }"
+        "QScrollBar::handle:horizontal:hover { background: #FFB232; }"
+        "QScrollBar::add-line:horizontal, QScrollBar::sub-line:horizontal { width: 0; }"
+        "QToolBar { background: #111111; border-bottom: 1px solid #2a2a2a; spacing: 4px; }"
+        "QDockWidget { border: none; }"
+        "QDockWidget::title { background: #1e1e1e; padding: 4px 8px; font-weight: bold; }"
+        "QTreeView, QTreeWidget { border: none; outline: none; }"
+        "QTreeView::item:selected, QTreeWidget::item:selected { color: #101010; }"
+        "QHeaderView::section { background: #1e1e1e; border: none;"
+        "  border-right: 1px solid #2a2a2a; padding: 4px 8px; }"
+        "QMenu { background: #1e1e1e; border: 1px solid #3a3a3a; }"
+        "QMenu::item:selected { background: #FFB232; color: #101010; }"
+        "QPushButton { background: #2a2a2a; border: 1px solid #3a3a3a; border-radius: 4px; padding: 4px 12px; }"
+        "QPushButton:hover { background: #333333; border-color: #FFB232; }"
+        "QPushButton:pressed { background: #FFB232; color: #101010; }"
+        "QComboBox { background: #2a2a2a; border: 1px solid #3a3a3a; border-radius: 4px; padding: 3px 8px; }"
+        "QComboBox:hover { border-color: #FFB232; }"
+        "QComboBox QAbstractItemView { background: #1e1e1e; selection-background-color: #FFB232; selection-color: #101010; }"
+        "QLineEdit { background: #1e1e1e; border: 1px solid #3a3a3a; border-radius: 4px; padding: 4px 8px; }"
+        "QLineEdit:focus { border-color: #FFB232; }"
+        "QGroupBox { border: 1px solid #2f2f2f; border-radius: 6px; margin-top: 8px; padding-top: 4px; }"
+        "QGroupBox::title { subcontrol-origin: margin; left: 8px; color: #FFB232; }"
+        "QCheckBox::indicator:checked { background: #FFB232; border: 1px solid #FFB232; border-radius: 2px; }"
+        "QSlider::groove:horizontal { height: 4px; background: #2a2a2a; border-radius: 2px; }"
+        "QSlider::handle:horizontal { background: #FFB232; width: 12px; height: 12px;"
+        "  margin: -4px 0; border-radius: 6px; }"
+        "QSlider::sub-page:horizontal { background: #FFB232; border-radius: 2px; }"
+        "QStatusBar { background: #111111; border-top: 1px solid #2a2a2a; }"
+    ));
+
     auto *backend = new QobuzBackend;
     MainWindow window(backend);
     window.show();

src/mainwindow.cpp

@@ -78,11 +78,24 @@ MainWindow::MainWindow(QobuzBackend *backend, QWidget *parent)
     connect(m_backend, &QobuzBackend::albumLoaded,      this, &MainWindow::onAlbumLoaded);
     connect(m_backend, &QobuzBackend::artistLoaded,     this, &MainWindow::onArtistLoaded);
     connect(m_backend, &QobuzBackend::playlistLoaded,   this, &MainWindow::onPlaylistLoaded);
+    connect(m_backend, &QobuzBackend::playlistCreated,   this, &MainWindow::onPlaylistCreated);
+    connect(m_backend, &QobuzBackend::playlistDeleted,   this, [this](const QJsonObject &) {
+        statusBar()->showMessage(tr("Playlist deleted"), 3000);
+    });
     connect(m_backend, &QobuzBackend::trackChanged,   this, &MainWindow::onTrackChanged);
     connect(m_backend, &QobuzBackend::error, this, [this](const QString &msg) {
         statusBar()->showMessage(tr("Error: %1").arg(msg), 6000);
     });
 
+    // ---- Library signals ----
+    connect(m_library, &List::Library::userPlaylistsChanged,
+            this, &MainWindow::onUserPlaylistsChanged);
+    connect(m_library, &List::Library::openPlaylistDeleted,
+            this, [this] {
+        m_content->showWelcome();
+        statusBar()->showMessage(tr("Playlist deleted"), 3000);
+    });
+
     // ---- Library → backend ----
     connect(m_library, &List::Library::favTracksRequested, this, [this] {
         m_backend->getFavTracks();
@@ -102,9 +115,19 @@ MainWindow::MainWindow(QobuzBackend *backend, QWidget *parent)
         statusBar()->showMessage(tr("Loading playlist: %1…").arg(name));
     });
 
-    // ---- Track list → playback ----
+    // ---- Track list → playback / playlist management ----
     connect(m_content->tracksList(), &List::Tracks::playTrackRequested,
             this, &MainWindow::onPlayTrackRequested);
+    connect(m_content->tracksList(), &List::Tracks::addToPlaylistRequested,
+            this, [this](qint64 trackId, qint64 playlistId) {
+        m_backend->addTrackToPlaylist(playlistId, trackId);
+        statusBar()->showMessage(tr("Adding track to playlist…"), 3000);
+    });
+    connect(m_content->tracksList(), &List::Tracks::removeFromPlaylistRequested,
+            this, [this](qint64 playlistId, qint64 playlistTrackId) {
+        m_backend->deleteTrackFromPlaylist(playlistId, playlistTrackId);
+        statusBar()->showMessage(tr("Removing track from playlist…"), 3000);
+    });
 
     // ---- Search panel ----
     connect(m_sidePanel, &SidePanel::View::albumSelected,
@@ -129,6 +152,9 @@ MainWindow::MainWindow(QobuzBackend *backend, QWidget *parent)
     connect(m_toolBar, &MainToolBar::queueToggled,
             this, [this](bool v) { m_queuePanel->setVisible(v); });
 
+    // Apply playback options from saved settings
+    m_backend->setReplayGain(AppSettings::instance().replayGainEnabled());
+
     tryRestoreSession();
 }
 
@@ -233,6 +259,16 @@ void MainWindow::onTrackChanged(const QJsonObject &track)
         : track["performer"].toObject()["name"].toString();
     statusBar()->showMessage(
         artist.isEmpty() ? title : QStringLiteral("▶  %1 — %2").arg(artist, title));
+
+    // Gapless: prefetch next track URL so it starts immediately
+    if (AppSettings::instance().gaplessEnabled() && m_queue->canGoNext()) {
+        const auto upcoming = m_queue->upcomingTracks(1);
+        if (!upcoming.isEmpty()) {
+            const qint64 nextId = static_cast<qint64>(upcoming.first()["id"].toDouble());
+            if (nextId > 0)
+                m_backend->prefetchTrack(nextId, AppSettings::instance().preferredFormat());
+        }
+    }
 }
 
 void MainWindow::onFavTracksLoaded(const QJsonObject &result)
@@ -298,3 +334,15 @@ void MainWindow::onSearchToggled(bool visible)
 {
     m_sidePanel->setVisible(visible);
 }
+
+void MainWindow::onPlaylistCreated(const QJsonObject &playlist)
+{
+    statusBar()->showMessage(
+        tr("Playlist '%1' created").arg(playlist["name"].toString()), 4000);
+}
+
+void MainWindow::onUserPlaylistsChanged(const QVector<QPair<qint64, QString>> &playlists)
+{
+    m_userPlaylists = playlists;
+    m_content->tracksList()->setUserPlaylists(playlists);
+}

src/mainwindow.hpp

@@ -13,6 +13,9 @@
 #include <QMainWindow>
 #include <QDockWidget>
 #include <QJsonObject>
+#include <QVector>
+#include <QPair>
+#include <QString>
 
 class MainWindow : public QMainWindow
 {
@@ -38,6 +41,8 @@ private slots:
     void onSearchAlbumSelected(const QString &albumId);
     void onSearchArtistSelected(qint64 artistId);
     void onSearchToggled(bool visible);
+    void onPlaylistCreated(const QJsonObject &playlist);
+    void onUserPlaylistsChanged(const QVector<QPair<qint64, QString>> &playlists);
 
     void showLoginDialog();
     void showSettingsDialog();
@@ -45,6 +50,7 @@ private slots:
 private:
     QobuzBackend    *m_backend     = nullptr;
     PlayQueue       *m_queue       = nullptr;
+    QVector<QPair<qint64, QString>> m_userPlaylists;
     MainToolBar     *m_toolBar     = nullptr;
     MainContent     *m_content     = nullptr;
     List::Library   *m_library     = nullptr;

src/model/tracklistmodel.cpp

@@ -22,6 +22,7 @@ void TrackListModel::setTracks(const QJsonArray &tracks,
         const QJsonObject t = v.toObject();
         TrackItem item;
         item.id               = static_cast<qint64>(t["id"].toDouble());
+        item.playlistTrackId  = static_cast<qint64>(t["playlist_track_id"].toDouble());
         item.title            = t["title"].toString();
         item.duration         = static_cast<qint64>(t["duration"].toDouble());
         item.hiRes      = t["hires_streamable"].toBool();
@@ -68,6 +69,14 @@ void TrackListModel::clear()
     endResetModel();
 }
 
+void TrackListModel::removeTrack(int row)
+{
+    if (row < 0 || row >= m_tracks.size()) return;
+    beginRemoveRows({}, row, row);
+    m_tracks.removeAt(row);
+    endRemoveRows();
+}
+
 void TrackListModel::setPlayingId(qint64 id)
 {
     m_playingId = id;
@@ -111,8 +120,8 @@ QVariant TrackListModel::data(const QModelIndex &index, int role) const
     }
 
     if (role == Qt::ForegroundRole) {
-        if (!t.streamable) return QColor(Qt::gray);
+        if (!t.streamable) return QColor(0x55, 0x55, 0x55);
-        if (isPlaying)     return QColor(0x1d, 0xb9, 0x54); // Qobuz green
+        if (isPlaying)     return QColor(0xFF, 0xB2, 0x32); // Qobuz orange
     }
 
     if (role == Qt::DecorationRole && index.column() == ColNumber && isPlaying) {
@@ -122,6 +131,7 @@ QVariant TrackListModel::data(const QModelIndex &index, int role) const
     if (role == TrackIdRole)         return t.id;
     if (role == TrackJsonRole)       return t.raw;
     if (role == HiResRole)           return t.hiRes;
+    if (role == PlaylistTrackIdRole) return t.playlistTrackId;
 
     return {};
 }

src/model/tracklistmodel.hpp

@@ -8,6 +8,7 @@
 
 struct TrackItem {
     qint64  id              = 0;
+    qint64  playlistTrackId = 0;
     int     number          = 0;
     QString title;
     QString artist;
@@ -37,6 +38,7 @@ public:
         TrackIdRole         = Qt::UserRole + 1,
         TrackJsonRole       = Qt::UserRole + 2,
         HiResRole           = Qt::UserRole + 3,
+        PlaylistTrackIdRole = Qt::UserRole + 4,
     };
 
     explicit TrackListModel(QObject *parent = nullptr);
@@ -50,6 +52,9 @@ public:
     void setPlayingId(qint64 id);
     qint64 playingId() const { return m_playingId; }
 
+    /// Optimistically remove a row (e.g. after deleting from playlist).
+    void removeTrack(int row);
+
     const TrackItem &trackAt(int row) const { return m_tracks.at(row); }
 
     // Returns the current (possibly sorted) raw JSON objects in display order.

src/util/settings.hpp

@@ -31,6 +31,13 @@ public:
     bool rememberLogin() const       { return m_settings.value("auth/remember", true).toBool(); }
     void setRememberLogin(bool r)    { m_settings.setValue("auth/remember", r); }
 
+    // --- Playback extras ---
+    bool replayGainEnabled() const     { return m_settings.value("playback/replaygain", false).toBool(); }
+    void setReplayGainEnabled(bool v)  { m_settings.setValue("playback/replaygain", v); }
+
+    bool gaplessEnabled() const        { return m_settings.value("playback/gapless", false).toBool(); }
+    void setGaplessEnabled(bool v)     { m_settings.setValue("playback/gapless", v); }
+
     // --- Last.fm ---
     bool    lastFmEnabled()   const  { return m_settings.value("lastfm/enabled", false).toBool(); }
     void    setLastFmEnabled(bool v) { m_settings.setValue("lastfm/enabled", v); }

src/view/albumlistview.hpp

@@ -58,7 +58,7 @@ public:
             auto *item = new QTreeWidgetItem(this);
             if (hiRes) {
                 item->setText(0, QStringLiteral("H"));
-                item->setForeground(0, QColor(QStringLiteral("#FFD700")));
+                item->setForeground(0, QColor(QStringLiteral("#FFB232")));
                 item->setFont(0, hiResFont);
                 item->setTextAlignment(0, Qt::AlignCenter);
             }

src/view/queuepanel.cpp

@@ -23,7 +23,7 @@ public:
 
     QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &) const override
     {
-        return QSize(0, QFontMetrics(option.font).height() + 10);
+        return QSize(0, QFontMetrics(option.font).height() + 4);
     }
 
     void paint(QPainter *p, const QStyleOptionViewItem &option,

src/view/sidepanel/view.cpp

@@ -105,7 +105,7 @@ void SearchTab::onSearchResult(const QJsonObject &result)
                 QStringList{QString(), a["title"].toString(), artist});
             if (hiRes) {
                 item->setText(0, QStringLiteral("H"));
-                item->setForeground(0, QColor(QStringLiteral("#FFD700")));
+                item->setForeground(0, QColor(QStringLiteral("#FFB232")));
                 item->setFont(0, hiResFont);
                 item->setTextAlignment(0, Qt::AlignCenter);
             }