diff --git a/.github/workflows/check_tests.yml b/.github/workflows/check_tests.yml
index 4152a05..7ba7244 100644
--- a/.github/workflows/check_tests.yml
+++ b/.github/workflows/check_tests.yml
@@ -4,9 +4,9 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
       - name: Set up Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236 # v4
         with:
           python-version: '3.x'  # Specify the Python version you want to use
           cache: pip
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index c63feb9..dd882e9 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -4,10 +4,12 @@ jobs:
   ruff:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      # Run ruff linter:
-      - uses: chartboost/ruff-action@v1
-      # Run ruff linter for formatting:
-      - uses: chartboost/ruff-action@v1
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+      
+      # Run ruff linter
+      - uses: chartboost/ruff-action@e18ae971ccee1b2d7bbef113930f00c670b78da4 # v1
+      
+      # Run ruff format
+      - uses: chartboost/ruff-action@e18ae971ccee1b2d7bbef113930f00c670b78da4 # v1
         with:
           args: 'format --check'
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index a60afab..6da74b2 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -15,15 +15,15 @@ jobs:
     
     steps:
       - name: "Checkout code"
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
 
       - name: Set up Python 3.9
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@42375524e23c412d93fb67b49958b491fce71c38 # v5
         with:
           python-version: "3.9"
 
       - name: Setup pdm
-        uses: pdm-project/setup-pdm@v3
+        uses: pdm-project/setup-pdm@ddc33ca746b5716353581f988b29464200212702 # v3
         with:
           python-version: "3.9"
           cache: true
@@ -32,4 +32,4 @@ jobs:
         run: pdm build
       
       - name: Publish package distributions to PyPI
-        uses: pypa/gh-action-pypi-publish@release/v1
\ No newline at end of file
+        uses: pypa/gh-action-pypi-publish@76f52bc884231f62b9a034ebfe128415bbaabdfc # release/v1
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index ead052a..5a652a9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -84,4 +84,6 @@ venv.bak/
 pixi.lock
 
 .stack-pr.cfg
-.vscode
\ No newline at end of file
+.vscode
+
+.DS_Store