add permalinks for program headings

_includes/program.css

@@ -18,6 +18,31 @@
   margin-right: 2px;
 }
 
+.permalink {
+  color: inherit;
+  font-size: inherit;
+  font-weight: inherit;
+  text-decoration: none;
+  position: relative;
+}
+
+.permalink::before {
+  content: "#";
+  color: var(--color-permalink);
+  font-size: .7em;
+  display: inline-flex;
+  align-items: center;
+  visibility: hidden;
+  position: absolute;
+  left: -1.3rem;
+  top: 0;
+  bottom: 0;
+}
+
+.permalink:hover::before {
+  visibility: visible;
+}
+
 .timeslot-container {
   position: relative;
   padding-top: 40px;