diff --git a/docs/bnf/index.md b/docs/bnf/index.md
index 5a2e653..a15b9a7 100644
--- a/docs/bnf/index.md
+++ b/docs/bnf/index.md
@@ -1,4 +1,4 @@
-# Backus-Naur Grammar
+# Backus-Naur Grammar (Deprecated)
 
 HDF5/JSON specification in the Backus-Naur form.
 
diff --git a/docs/requirements.txt b/docs/requirements.txt
index 7e43525..9a17746 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,4 +1,4 @@
 file:.#egg=h5json
-sphinx-book-theme
+sphinx-book-theme==1.1.3
 sphinx-copybutton
 myst-parser
diff --git a/docs/schema/index.md b/docs/schema/index.md
index b22c6bc..12a5a0f 100644
--- a/docs/schema/index.md
+++ b/docs/schema/index.md
@@ -1,4 +1,4 @@
-# JSON Schema
+# JSON Schema (**Normative**)
 
 HDF5/JSON specification as JSON Schema.
 
diff --git a/docs/specs.md b/docs/specs.md
index ea2e32c..fc73dff 100644
--- a/docs/specs.md
+++ b/docs/specs.md
@@ -3,6 +3,6 @@
 ```{toctree}
 :maxdepth: 1
 
-bnf/index
 schema/index
+bnf/index
 ```