similar pseudo-applet styling added to _scroll.html

src/static_src/scss/_billboard.scss

@@ -47,12 +47,11 @@ body.page-billscroll {
 
     // The single scroll applet stretches to fill the remaining aperture
     .applet-billboard-scroll {
+        @extend %applet-box;
         flex: 1;
         min-height: 0;
         display: flex;
         flex-direction: column;
-        // Override grid-row span — this applet fills height via flex, not grid rows
-        grid-row: unset;
 
         #id_drama_scroll {
             flex: 1;