Trim intro copy and give it a supporting image

The intro was the only slide/page without a graphic. Shortened it to two
sentences and added a matching photo, and dropped the CSS rule that let
Step 1 share a print page with the intro (needed now that the intro has
its own image and deserves a full page like every other section).

style.css

@@ -52,16 +52,14 @@ a {
   margin: 1.5rem 0 0;
 }
 
-/* One Step per page, like the original PDF */
+/* One Step per page, like the original PDF. The intro (before Step 1) now
+   carries its own image too, so it gets a full page like every other
+   section instead of sharing Step 1's page. */
 h2 {
   page-break-before: always;
   font-size: 1.5rem;
 }
 
-h2:first-of-type {
-  page-break-before: avoid;
-}
-
 img {
   max-width: 100%;
   border-radius: 0.5rem;