diff --git a/doc/_themes/ceph/static/nature.css_t b/doc/_themes/ceph/static/nature.css_t
index 92e42567a1f..71fb56f4d91 100644
--- a/doc/_themes/ceph/static/nature.css_t
+++ b/doc/_themes/ceph/static/nature.css_t
@@ -196,7 +196,7 @@ div.admonition p.admonition-title + p {
     display: inline;
 }
 
-div.highlight{
+div.highlight {
     background-color: white;
 }
 
@@ -302,3 +302,9 @@ dl.glossary dt {
 	padding-top:20px;	
 
 }
+
+p.breathe-sectiondef-title {
+    font-size: 1.3em;
+    font-weight: bold;
+    border-bottom: thin solid #5E6A71;
+}