diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2dc5036..7d70c3b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,29 +1,65 @@
 name: CI
 
-on: [push, pull_request]
+on:
+  push:
+    branches: [master, main]
+  pull_request:
+
+env:
+  CARGO_TERM_COLOR: always
 
 jobs:
   test:
-    name: Cargo Test
-    runs-on: ubuntu-latest
+    name: Test (${{ matrix.os }})
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.head.sha }}
 
-      - uses: taiki-e/install-action@v2
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt, clippy
+
+      - name: Install tools
+        uses: taiki-e/install-action@v2
         with:
           tool: just,cargo-nextest
 
+      - name: Cache Dependencies
+        uses: Swatinem/rust-cache@v2
+
+      - name: Run CI checks
+        run: just ci
+
+  features:
+    name: Feature Combinations
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+
       - name: Install Rust toolchain
-        run: |
-          rustup update --no-self-update stable
-          rustup component add --toolchain stable rustfmt rust-src
-          rustup default stable
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install tools
+        uses: taiki-e/install-action@v2
+        with:
+          tool: just,cargo-nextest
 
       - name: Cache Dependencies
-        uses: Swatinem/rust-cache@640a22190e7a783d4c409684cea558f081f92012
+        uses: Swatinem/rust-cache@v2
 
-      - name: Test
-        run: just ci
+      - name: Test feature combinations
+        run: just features
+
+      - name: Test with all features
+        run: just test-all-features
diff --git a/Justfile b/Justfile
index 5366cae..2c5bc84 100644
--- a/Justfile
+++ b/Justfile
@@ -1,14 +1,42 @@
+# Cross-platform CI tasks
 ci:
     just test
     just nostd
     just clippy
     cargo fmt --check --all
 
+# Run tests using cargo-nextest
+test *args:
+    cargo nextest run {{args}}
+
+# Check no_std compatibility
 nostd:
     cargo check --no-default-features -p pk2
 
+# Run clippy lints
 clippy:
     cargo clippy --workspace --all-targets --all-features -- -D warnings
 
-test *args:
-    cargo nextest run {{args}} < /dev/null
+# Feature matrix testing
+features:
+    @echo "Testing no default features..."
+    cargo check --no-default-features -p pk2
+    @echo "Testing std feature only..."
+    cargo check --no-default-features --features std -p pk2
+    @echo "Testing euc-kr feature only..."
+    cargo check --no-default-features --features euc-kr -p pk2
+    @echo "Testing all features..."
+    cargo check --all-features --workspace
+    @echo "All feature combinations passed!"
+
+# Run tests with all features
+test-all-features:
+    cargo nextest run --workspace --all-features
+
+# Build documentation
+docs:
+    cargo doc --workspace --no-deps --document-private-items
+
+# Clean build artifacts
+clean:
+    cargo clean