diff --git a/docs/_static/css/custom.css b/docs/_static/css/custom.css
index b33b570d..82770653 100644
--- a/docs/_static/css/custom.css
+++ b/docs/_static/css/custom.css
@@ -92,6 +92,10 @@ h3 {
   font-weight: 700;
 }
 
+h4 {
+  font-size: 18px;
+}
+
 /* Keep link color for visited links */
 a:visited {
   color: var(--pst-color-link);