--- a/etc/isabelle.css	Wed May 31 21:37:50 2017 +0200
+++ b/etc/isabelle.css	Wed May 31 21:48:32 2017 +0200
@@ -40,8 +40,6 @@
 .theories { background-color: #FFFFFF; padding: 10px; }
 .sessions { background-color: #FFFFFF; padding: 10px; }
 
-.sessions pre { margin: 0px; }
-
 .name     { font-style: italic; }
 .filename { font-family: fixed; }
 
--- a/src/Pure/Thy/present.scala	Wed May 31 21:37:50 2017 +0200
+++ b/src/Pure/Thy/present.scala	Wed May 31 21:48:32 2017 +0200
@@ -53,10 +53,10 @@
        (if (sessions.isEmpty) Nil
         else
           List(HTML.css_class("sessions")(HTML.div(List(
-            HTML.itemize(
+            HTML.description(
               sessions.map({ case (name, description) =>
-                HTML.link(name + "/index.html", HTML.text(name)) ::
-                 (if (description == "") Nil
+                (List(HTML.link(name + "/index.html", HTML.text(name))),
+                  if (description == "") Nil
                   else List(HTML.pre(HTML.text(description)))) }))))))))
   }