diff --git a/documentation/content/en/books/fdp-primer/writing-style/_index.adoc b/documentation/content/en/books/fdp-primer/writing-style/_index.adoc
--- a/documentation/content/en/books/fdp-primer/writing-style/_index.adoc
+++ b/documentation/content/en/books/fdp-primer/writing-style/_index.adoc
@@ -14,7 +14,7 @@
 = Writing Style
 :doctype: book
 :toc: macro
-:toclevels: 1
+:toclevels: 2
 :icons: font
 :sectnums:
 :sectnumlevels: 6
@@ -169,7 +169,7 @@
 To keep the source for the documentation consistent when many different people are editing it, please follow these style conventions.
 
 [[one-sentence-per-line]]
-== One sentence per line
+=== One sentence per line
 
 Use Semantic Line Breaks in the documentation, a technique called "one sentence per line".
 The idea of this technique is to help the users to write and read documentation.
@@ -189,7 +189,7 @@
 ....
 
 [[writing-style-acronyms]]
-== Acronyms
+=== Acronyms
 
 Acronyms should be defined the first time they appear in a document, as in: "Network Time Protocol (NTP)".
 After the acronym has been defined, use the acronym alone unless it makes more sense contextually to use the whole term.