diff --git a/.gitignore b/.gitignore
index 860aa41..5a61e45 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,6 @@ result/**/*
 #.idea/
 #
 .direnv
+
+# ignore (possible) sound files
+**/*.{mp3,wav}
diff --git a/.rustfmt.toml b/.rustfmt.toml
index 44148a2..49013dd 100644
--- a/.rustfmt.toml
+++ b/.rustfmt.toml
@@ -1 +1,2 @@
+style_edition = "2024"
 reorder_imports = true
diff --git a/Cargo.toml b/Cargo.toml
index 576f3af..6c790fc 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,8 +2,9 @@
 name = "timr-tui"
 version = "1.1.0"
 description = "TUI to organize your time: Pomodoro, Countdown, Timer."
-edition = "2021"
-rust-version = "1.84.0"
+edition = "2024"
+# Reminder: Always keep `channel` in `rust-toolchain.toml` in sync with `rust-version`.
+rust-version = "1.85.0"
 homepage = "https://github.com/sectore/timr-tui"
 repository = "https://github.com/sectore/timr-tui"
 readme = "README.md"
diff --git a/flake.lock b/flake.lock
index 41861cc..6834ce2 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,11 +2,11 @@
   "nodes": {
     "crane": {
       "locked": {
-        "lastModified": 1738652123,
-        "narHash": "sha256-zdZek5FXK/k95J0vnLF0AMnYuZl4AjARq83blKuJBYY=",
+        "lastModified": 1739936662,
+        "narHash": "sha256-x4syUjNUuRblR07nDPeLDP7DpphaBVbUaSoeZkFbGSk=",
         "owner": "ipetkov",
         "repo": "crane",
-        "rev": "c7e015a5fcefb070778c7d91734768680188a9cd",
+        "rev": "19de14aaeb869287647d9461cbd389187d8ecdb7",
         "type": "github"
       },
       "original": {
@@ -23,11 +23,11 @@
         "rust-analyzer-src": "rust-analyzer-src"
       },
       "locked": {
-        "lastModified": 1738650687,
-        "narHash": "sha256-1tvCUR1+/F3IT1K4QHTcEO+vsip/P1iluPIttX57Ry8=",
+        "lastModified": 1740378829,
+        "narHash": "sha256-cwmm7F73aQFJY6YN1roNibNKwxT6FlfXkG3MEbpSp7Q=",
         "owner": "nix-community",
         "repo": "fenix",
-        "rev": "37a1f29ebf98fbbac667730edc5dab4ebe2e3954",
+        "rev": "92823f1b0c919d7e2d806956aaf98e90f3761ab7",
         "type": "github"
       },
       "original": {
@@ -56,11 +56,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1738546358,
-        "narHash": "sha256-nLivjIygCiqLp5QcL7l56Tca/elVqM9FG1hGd9ZSsrg=",
+        "lastModified": 1740367490,
+        "narHash": "sha256-WGaHVAjcrv+Cun7zPlI41SerRtfknGQap281+AakSAw=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "c6e957d81b96751a3d5967a0fd73694f303cc914",
+        "rev": "0196c0175e9191c474c26ab5548db27ef5d34b05",
         "type": "github"
       },
       "original": {
@@ -81,11 +81,11 @@
     "rust-analyzer-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1738591430,
-        "narHash": "sha256-Q4tPO6rH/q41IZG+NGy/Pjd2RW/bRDVjVjBh9LaVWE4=",
+        "lastModified": 1740329432,
+        "narHash": "sha256-eKQ7aBkNvF5AhUpyJ1cW450jxomZ4gTIaYir5qsNl7Y=",
         "owner": "rust-lang",
         "repo": "rust-analyzer",
-        "rev": "13c17db07b1201e3c460b4cc0ee49ac4d0ace0e5",
+        "rev": "6d68c475c7aaf7534251182662456a4bf4216dfe",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index 49ac421..0e67c40 100644
--- a/flake.nix
+++ b/flake.nix
@@ -18,31 +18,32 @@
   }:
     flake-utils.lib.eachDefaultSystem (system: let
       pkgs = nixpkgs.legacyPackages.${system};
-      toolchain = with fenix.packages.${system};
-        combine [
-          minimal.rustc
-          minimal.cargo
-          targets.x86_64-pc-windows-gnu.latest.rust-std
-          targets.x86_64-unknown-linux-musl.latest.rust-std
-        ];
+
+      toolchain =
+        fenix.packages.${system}.fromToolchainFile
+        {
+          file = ./rust-toolchain.toml;
+          # sha256 = nixpkgs.lib.fakeSha256;
+          sha256 = "sha256-AJ6LX/Q/Er9kS15bn9iflkUwcgYqRQxiOIL2ToVAXaU=";
+        };
+
       craneLib = (crane.mkLib pkgs).overrideToolchain toolchain;
 
-      # Common build inputs for both native and cross compilation
       commonArgs = {
         src = craneLib.cleanCargoSource ./.;
-        cargoArtifacts = craneLib.buildDepsOnly {
-          src = craneLib.cleanCargoSource ./.;
-        };
         strictDeps = true;
         doCheck = false; # skip tests during nix build
       };
 
+      cargoArtifacts = craneLib.buildDepsOnly commonArgs;
+
       # Native build
       timr = craneLib.buildPackage commonArgs;
 
       # Linux build w/ statically linked binaries
       staticLinuxBuild = craneLib.buildPackage (commonArgs
         // {
+          inherit cargoArtifacts;
           CARGO_BUILD_TARGET = "x86_64-unknown-linux-musl";
           CARGO_BUILD_RUSTFLAGS = "-C target-feature=+crt-static";
         });
@@ -75,14 +76,10 @@
         windows = windowsBuild;
       };
 
-      # Development shell with all necessary tools
-      devShell = with nixpkgs.legacyPackages.${system};
-        mkShell {
-          buildInputs = with fenix.packages.${system}.stable;
+      devShells.default = with nixpkgs.legacyPackages.${system};
+        craneLib.devShell {
+          packages =
             [
-              rust-analyzer
-              clippy
-              rustfmt
               toolchain
               pkgs.just
               pkgs.nixd
@@ -96,7 +93,7 @@
             ];
 
           inherit (commonArgs) src;
-          RUST_SRC_PATH = "${toolchain}/lib/rustlib/src/rust/library";
+
           ALSA_PLUGIN_DIR =
             if stdenv.isLinux
             then "${pkgs.pipewire}/lib/alsa-lib/"
diff --git a/justfile b/justfile
index b75e628..eac8df2 100644
--- a/justfile
+++ b/justfile
@@ -6,32 +6,42 @@ default:
     @just --list
 
 alias b := build
-alias f := format
-alias l := lint
-alias t := test
-alias r := run
 
 # build app
 build:
     cargo build
 
+alias t := test
+
 # run tests
 test:
     cargo test
 
+alias f := format
+
 # format files
 format:
     just --fmt
     cargo fmt
 
+alias l := lint
+
 # lint
 lint:
     cargo clippy --no-deps
 
+alias r := run
+
 # run app
 run:
     cargo run
 
+alias rs := run-sound
+
+# run app while sound feature is enabled. It expects a path to a sound file.
+run-sound path:
+    cargo run --features sound -- --sound={{ path }}
+
 # demos
 
 alias dp := demo-pomodoro
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 0000000..19e1540
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,6 @@
+[toolchain]
+# Reminder: Always keep `rust-version` in `Cargo.toml` in sync with `channel`.
+channel = "1.85.0"
+components = ["clippy", "rustfmt", "rust-src", "rust-analyzer"]
+targets = ["x86_64-pc-windows-gnu", "x86_64-unknown-linux-musl"]
+profile = "minimal"
diff --git a/src/common.rs b/src/common.rs
index a05da49..656bb97 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -1,8 +1,8 @@
 use clap::ValueEnum;
 use ratatui::symbols::shade;
 use serde::{Deserialize, Serialize};
-use time::format_description;
 use time::OffsetDateTime;
+use time::format_description;
 
 #[derive(
     Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, ValueEnum, Default, Serialize, Deserialize,
diff --git a/src/config.rs b/src/config.rs
index 9434f3c..be58afe 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,5 +1,5 @@
 use crate::constants::APP_NAME;
-use color_eyre::eyre::{eyre, Result};
+use color_eyre::eyre::{Result, eyre};
 use directories::ProjectDirs;
 use std::fs;
 use std::path::PathBuf;
diff --git a/src/duration.rs b/src/duration.rs
index 816096f..8275cd7 100644
--- a/src/duration.rs
+++ b/src/duration.rs
@@ -1,6 +1,6 @@
 use color_eyre::{
-    eyre::{ensure, eyre},
     Report,
+    eyre::{ensure, eyre},
 };
 use std::fmt;
 use std::time::Duration;
diff --git a/src/events.rs b/src/events.rs
index 3321488..8bc231c 100644
--- a/src/events.rs
+++ b/src/events.rs
@@ -3,7 +3,7 @@ use futures::{Stream, StreamExt};
 use std::{pin::Pin, time::Duration};
 use tokio::sync::mpsc;
 use tokio::time::interval;
-use tokio_stream::{wrappers::IntervalStream, StreamMap};
+use tokio_stream::{StreamMap, wrappers::IntervalStream};
 
 use crate::common::ClockTypeId;
 use crate::constants::{FPS_VALUE_MS, TICK_VALUE_MS};
diff --git a/src/logging.rs b/src/logging.rs
index 0d8942c..83795da 100644
--- a/src/logging.rs
+++ b/src/logging.rs
@@ -1,4 +1,4 @@
-use color_eyre::eyre::{eyre, Result};
+use color_eyre::eyre::{Result, eyre};
 use std::fs;
 use std::path::PathBuf;
 use tracing::level_filters::LevelFilter;
diff --git a/src/terminal.rs b/src/terminal.rs
index a6d7509..cc6f3e3 100644
--- a/src/terminal.rs
+++ b/src/terminal.rs
@@ -5,7 +5,7 @@ use crossterm::{
     cursor, execute,
     terminal::{EnterAlternateScreen, LeaveAlternateScreen},
 };
-use ratatui::{backend::CrosstermBackend, Terminal as RatatuiTerminal};
+use ratatui::{Terminal as RatatuiTerminal, backend::CrosstermBackend};
 
 pub type Terminal = RatatuiTerminal<CrosstermBackend<io::Stdout>>;
 
diff --git a/src/widgets/clock.rs b/src/widgets/clock.rs
index 8a06fe7..56a96b4 100644
--- a/src/widgets/clock.rs
+++ b/src/widgets/clock.rs
@@ -15,7 +15,7 @@ use crate::{
     events::{AppEvent, AppEventTx},
     utils::center_horizontal,
     widgets::clock_elements::{
-        Colon, Digit, Dot, COLON_WIDTH, DIGIT_HEIGHT, DIGIT_SPACE_WIDTH, DIGIT_WIDTH, DOT_WIDTH,
+        COLON_WIDTH, Colon, DIGIT_HEIGHT, DIGIT_SPACE_WIDTH, DIGIT_WIDTH, DOT_WIDTH, Digit, Dot,
     },
 };
 
diff --git a/src/widgets/edit_time.rs b/src/widgets/edit_time.rs
index 9a709bd..c91ccb2 100644
--- a/src/widgets/edit_time.rs
+++ b/src/widgets/edit_time.rs
@@ -9,7 +9,7 @@ use ratatui::{
 
 use crate::{
     common::Style,
-    widgets::clock_elements::{Colon, Digit, COLON_WIDTH, DIGIT_SPACE_WIDTH, DIGIT_WIDTH},
+    widgets::clock_elements::{COLON_WIDTH, Colon, DIGIT_SPACE_WIDTH, DIGIT_WIDTH, Digit},
 };
 
 use super::clock_elements::DIGIT_HEIGHT;