Index: src/accordion.js
==================================================================
--- src/accordion.js
+++ src/accordion.js
@@ -1,8 +1,8 @@
-# Attach appropriate javascript to each ".accordion" button so that
-# it expands and contracts when clicked.
-#
+/* Attach appropriate javascript to each ".accordion" button so that
+** it expands and contracts when clicked.
+*/
 var a = document.getElementsByClassName("accordion");
 for(var i=0; i<a.length; i++){
   var p = a[i].nextElementSibling;
   p.style.maxHeight = p.scrollHeight + "px";
   a[i].addEventListener("click",function(){

Index: src/default_css.txt
==================================================================
--- src/default_css.txt
+++ src/default_css.txt
@@ -811,18 +811,21 @@
 }
 .nobr {
   white-space: nowrap;
 }
 .accordion {
+  padding-left: 30px;
+//Note: the mkcss utility does not support line breaks in data URIs.
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath style='fill:black;opacity:0' d='M16,16H0V0h16v16z'/%3E%3Cpath style='fill:rgb(240,240,240)' d='M14,14H2V2h12v12z'/%3E%3Cpath style='fill:rgb(64,64,64)' d='M13,13H3V3h10v10z'/%3E%3Cpath style='fill:rgb(248,248,248)' d='M12,12H4V4h8v8z'/%3E%3Cpath style='fill:rgb(80,128,208)' d='M11,9H5V7h6v6z'/%3E%3C/svg%3E");
+  background-repeat: no-repeat;
+  background-position: 10px center;
+  background-size: 16px 16px;
   cursor: pointer;
 }
-.accordion:after {
-  content: '\02796';
-  margin-left: 1em;
-}
-.accordion_closed:after {
-  content: '\02795';
+.accordion_closed {
+//Note: the mkcss utility does not support line breaks in data URIs.
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath style='fill:black;opacity:0' d='M16,16H0V0h16v16z'/%3E%3Cpath style='fill:rgb(240,240,240)' d='M14,14H2V2h12v12z'/%3E%3Cpath style='fill:rgb(64,64,64)' d='M13,13H3V3h10v10z'/%3E%3Cpath style='fill:rgb(248,248,248)' d='M12,12H4V4h8v8z'/%3E%3Cpath style='fill:rgb(80,128,208)' d='M5,7h2v-2h2v2h2v2h-2v2h-2v-2h-2z'/%3E%3C/svg%3E");
 }
 .accordion_panel {
   overflow: hidden;
   transition: max-height 0.25s ease-out;
 }