Tweaked chapter list item styles

- Improves animation smoothness
- Changed animation slideup/down animations to use max-height instead of height
  to better avoid jutter at the end.
- Cleaned spacing to match page items in books listing.

resources/sass/_lists.scss

@@ -460,8 +460,7 @@ ul.pagination {
   padding: $-m;
   > div {
     overflow: hidden;
-    padding: $-xs 0;
-    margin-top: -$-xs;
+    padding: 0 0 $-xs 0;
   }
   .entity-chip {
     text-overflow: ellipsis;