diff --git a/doc/static/acrn-custom.css b/doc/static/acrn-custom.css
index c3b7445bc..5a4b37d4c 100644
--- a/doc/static/acrn-custom.css
+++ b/doc/static/acrn-custom.css
@@ -133,3 +133,24 @@ th,td {
 col.option {
   width: 25%;
 }
+
+/* tweak format for <kbd> (:kbd:`F10`) */
+kbd
+{
+  -moz-border-radius:3px;
+  -moz-box-shadow:0 1px 0 rgba(0,0,0,0.2),0 0 0 2px #fff inset;
+  -webkit-border-radius:3px;
+  -webkit-box-shadow:0 1px 0 rgba(0,0,0,0.2),0 0 0 2px #fff inset;
+  background-color:#f7f7f7;
+  border:1px solid #ccc;
+  border-radius:3px;
+  box-shadow:0 1px 0 rgba(0,0,0,0.2),0 0 0 2px #fff inset;
+  color:#333;
+  display:inline-block;
+  font-family:Arial,Helvetica,sans-serif;
+  font-size:11px;
+  line-height:1.4;
+  margin:0 .1em;
+  padding:.1em .6em;
+  text-shadow:0 1px 0 #fff;
+}