diff --git a/src/css/custom.css b/src/css/custom.css
index 8a1658c6..9f88273e 100644
--- a/src/css/custom.css
+++ b/src/css/custom.css
@@ -780,6 +780,18 @@ html[data-theme="dark"] h3 {
   color: var(--ifm-color-primary-lightest);
 }
 
+/* <h4> */
+.markdown h4 {
+  font-size: 1.3rem;
+}
+html[data-theme="light"] h4 {
+  color: #62b00d;
+}
+html[data-theme="dark"] h4 {
+  color: #83de1f;
+}
+
+
 /* <hr> */
 .markdown hr {
   border-bottom: none;