diff --git a/.github/workflows/book.yml b/.github/workflows/book.yml
index 466218e6a..4941de0da 100644
--- a/.github/workflows/book.yml
+++ b/.github/workflows/book.yml
@@ -11,10 +11,10 @@ jobs:
     concurrency:
       group: ${{ github.workflow }}-${{ github.ref }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Setup
-        uses: peaceiris/actions-mdbook@v1
+        uses: peaceiris/actions-mdbook@v2
         with:
           mdbook-version: 'latest'
 
@@ -22,7 +22,7 @@ jobs:
 
       # HTML publication as Github Page
       - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./docs/book
diff --git a/docs/book.toml b/docs/book.toml
index ca8668c1c..71b57bbae 100644
--- a/docs/book.toml
+++ b/docs/book.toml
@@ -1,10 +1,19 @@
 [book]
 authors = ["The Hash Programming Language authors"]
 language = "en"
-multilingual = false
 src = "src"
 title = "The Hash Programming Language"
 
+[build]
+build-dir = "book"
+create-missing = true
+extra-watch-dirs = []
+
 [output.html]
+default-theme = "light"
+preferred-dark-theme = "navy"
 git-repository-url = "https://github.com/hash-org/hashc"
-git-repository-icon = "fa-github"
+edit-url-template = "https://github.com/hash-org/hashc/edit/main/docs/{path}"
+site-url = "/hashc/"
+cname = ""
+smart-punctuation = true