give pdf look-and-feel to web version

style.css

@@ -368,6 +368,9 @@ li{
   font-style: normal;
 }
 
+/* make links functional for web,
+ * but not distracting for print
+ */
 a[href]{
   text-decoration: none;
   color: #444;
@@ -375,3 +378,18 @@ a[href]{
 a[href]:hover{
   text-decoration: underline;
 }
+
+/* make web version resemble printable page
+ */
+body{
+  background-color: grey;
+}
+body > *{
+  background-color: white;
+}
+#main{
+  height: var(--page-height);
+}
+#sidebar{
+  height: var(--page-height);
+}