diff --git a/book/syntax_exercises/013.md b/book/syntax_exercises/013.md
index 8fe41ba..4a1df77 100644
--- a/book/syntax_exercises/013.md
+++ b/book/syntax_exercises/013.md
@@ -106,8 +106,8 @@ sphinx:
 * `super`
 * `number`
 
-```{hint} What each reference style will look like
-:class: dropdown
+```{admonition} What each reference style will look like
+:class: hint, dropdown
 Heres's how each style will appear for the example in the shared bibliography:
 
 - `author_year` → Moore (2023)
@@ -135,8 +135,8 @@ Feeling brave? You can also use APA references, although this is not a default o
 - `unsrt`
 - `unsrtalpha`
 
-```{hint} What each bibliography style looks like
-:class: dropdown
+```{admonition} What each bibliography style looks like
+:class: hint, dropdown
 Heres's how each style will appear for the example in the shared bibliography:
 
 - `alpha` → References labelled as [Knu84], sorted by author/year