diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 3371427..dccd2c3 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -27,8 +27,8 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v7
-      - uses: actions/setup-node@v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/setup-node@949feb2413d6458794dcd2491c4babbbce0c15c1 # v7.1.0
         with:
           node-version: 24
           cache: npm
@@ -45,7 +45,7 @@ jobs:
       - run: npm run build
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      - uses: actions/upload-pages-artifact@v5
+      - uses: actions/upload-pages-artifact@fc324d3547104276b827a68afc52ff2a11cc49c9 # v5.0.0
         with:
           path: ./dist
 
@@ -57,4 +57,4 @@ jobs:
       url: ${{ steps.deployment.outputs.page_url }}
     steps:
       - id: deployment
-        uses: actions/deploy-pages@v5
+        uses: actions/deploy-pages@368f82528645a54fb793d4d04e342629a3f51346 # v5.0.1
diff --git a/.github/workflows/pr-build.yml b/.github/workflows/pr-build.yml
index 29ef4f5..26efa30 100644
--- a/.github/workflows/pr-build.yml
+++ b/.github/workflows/pr-build.yml
@@ -10,13 +10,18 @@ jobs:
   build:
     runs-on: ubuntu-latest
     timeout-minutes: 15
+    strategy:
+      fail-fast: false
+      matrix:
+        # The oldest Node that package.json engines allows, and the Node the deploy uses.
+        node: ['22.23.4', '24']
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
-      - uses: actions/setup-node@v7
+      - uses: actions/setup-node@949feb2413d6458794dcd2491c4babbbce0c15c1 # v7.1.0
         with:
-          node-version: 24
+          node-version: ${{ matrix.node }}
           cache: npm
       - run: npm ci
       - run: npx playwright install --with-deps chromium
diff --git a/.github/workflows/refresh-coverage-badges.yml b/.github/workflows/refresh-coverage-badges.yml
index 09d8f5b..83e0230 100644
--- a/.github/workflows/refresh-coverage-badges.yml
+++ b/.github/workflows/refresh-coverage-badges.yml
@@ -30,10 +30,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out main
-        uses: actions/checkout@v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
         with:
           python-version: '3.12'