UPD: more cool participant admin stuff.

dav_base/static/dav_base/css/local.css

@@ -140,4 +140,11 @@ thead input {
   content:"*";
   color: red;
 }
-*/
+*/
+
+/*
+ * Used to remove the space around link like buttons (<button class="btn btn-link no-padding">).
+ */
+.no-padding {
+    padding: 0px;
+}