chore: clean up css — generic styles where they make sense; remove deprecated styles, fragments of utility nonsense etc

src/pages/main/books/book.html

@@ -50,7 +50,7 @@ schema: book
   </div>
   {% if book.review %}
     {{ book.review | markdown }}
-    <hr class="large-spacing" />
+    <hr />
   {% endif %}
   {% if book.description %}
     <h2>Overview</h2>