diff --git a/.github/workflows/gh-pages.yml b/.github/workflows/gh-pages.yml
index 4aab62cc..90e6dd56 100644
--- a/.github/workflows/gh-pages.yml
+++ b/.github/workflows/gh-pages.yml
@@ -72,11 +72,16 @@ jobs:
       - name: Get Zotero Version Information
         id: zoteroVersion
         run: |
-          VERSION=$(curl -sI "https://api.zotero.org/groups/2914042/items?format=versions" \
+          set -euo pipefail
+          VERSION=$(curl -fsSLI "https://api.zotero.org/groups/2914042/items?format=versions" \
             | grep -i "last-modified-version" \
             | cut -d: -f2 \
-            | tr -d '\r ' )
-          echo "version=$VERSION" >> $GITHUB_OUTPUT
+            | tr -d $'\r ' )
+          if [[ -z "${VERSION:-}" ]]; then
+            echo "Error: Failed to determine Zotero Last-Modified-Version from API response." >&2
+            exit 1
+          fi
+          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
 
       - name: Cache Zotero Bibliography
         id: cache-zotero
@@ -172,8 +177,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          npm install -g autoprefixer postcss-cli
-          npm install
+          npm ci
 
       - name: Build
         env:
@@ -197,5 +201,5 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@v5