toggle heading-link visibility with CSS alone

IPython/frontend/html/notebook/static/notebook/js/textcell.js

@@ -515,14 +515,8 b' var IPython = (function (IPython) {'
                 .addClass('anchor-link')
                 .attr('href', '#' + link)
                 .html('¶')
-                .hide()
             )
         );
-        r.hover(function() {
-            r.find("a.anchor-link").show();
-        }, function() {
-            r.find("a.anchor-link").hide();
-        });
     };
 
 

IPython/frontend/html/notebook/static/notebook/less/textcell.less

@@ -27,4 +27,9 b' a.heading-anchor {'
 a.anchor-link:link {
   text-decoration: none;
   padding: 0px 20px;
+  visibility: hidden;
 }
+
+h1:hover .anchor-link {
+  visibility: visible;
+}
  No newline at end of file

IPython/frontend/html/notebook/static/style/style.min.css

@@ -1037,7 +1037,8 b' div.text_cell{padding:5px 5px 5px 5px;}'
 div.text_cell_input{color:#000000;border:1px solid #cfcfcf;border-radius:4px;background:#f7f7f7;}
 div.text_cell_render{outline:none;resize:none;width:inherit;border-style:none;padding:5px;color:#000000;}
 a.heading-anchor{text-decoration:none;color:inherit;}
-a.anchor-link:link{text-decoration:none;padding:0px 20px;}
+a.anchor-link:link{text-decoration:none;padding:0px 20px;visibility:hidden;}
+h1:hover .anchor-link{visibility:visible;}
 .toolbar{padding:3px 15px;border-bottom:1px #ababab solid;}.toolbar button{margin-top:2px;margin-bottom:2px;}
 .toolbar select,.toolbar label{height:19px;vertical-align:middle;margin-right:2px;margin-bottom:0;display:inline;font-size:92%;margin-left:0.3em;margin-right:0.3em;padding:0px;}
 .toolbar select{width:auto;}