Fix tables, clean popups.

Imagemap on categories is now broken, need to see how to fix

doc/synopsis/synopsis.css

@@ -1,5 +1,7 @@
+/* Quick links */
+
 #quicklinks {
-  line-height: 130%;
+  line-height: 140%;
 }
 
 #quicklinks.sidebar {
@@ -11,3 +13,23 @@
 #quicklinks a {
   display: block;
 }
+
+/* Reveal popup */
+
+.popup {
+  display: none;
+  background: #ffffccee;
+  border: 1px solid #dee2e6;
+  padding: 1em 1em 1em 0;
+}
+
+.reveal:hover .popup {
+  display: block;
+  position: absolute;
+  margin: 0 1em;
+}
+
+/* General */
+.table td, .table th {
+  padding: 0.5em .75rem;
+}