diff --git a/doc/_themes/sphinx13/layout.html b/doc/_themes/sphinx13/layout.html
index e8176da17..e9b2078f7 100644
--- a/doc/_themes/sphinx13/layout.html
+++ b/doc/_themes/sphinx13/layout.html
@@ -34,12 +34,13 @@
diff --git a/doc/_themes/sphinx13/static/sphinx13.css b/doc/_themes/sphinx13/static/sphinx13.css
index b4e040d7c..633a66a17 100644
--- a/doc/_themes/sphinx13/static/sphinx13.css
+++ b/doc/_themes/sphinx13/static/sphinx13.css
@@ -110,7 +110,8 @@ div.sphinxsidebar input {
}
div.sphinxsidebar h3 {
- font-size: 1.5em;
+ font-size: 1.2em;
+ font-weight: 300;
margin-top: 0;
margin-bottom: 0.5em;
padding-top: 0.5em;