Footer: add 1.25rem horizontal padding to align bars with hero edges

The hero is inside .site-main (which has padding: 1rem 1.25rem 0.2rem),
so its rendered width is 975px - 40px = 935px. The footer was outside
site-main with no horizontal padding, making its bars span the full
975px. Add the matching 1.25rem horizontal padding to .site-footer so
the bar pair aligns to the same pixel column as the hero banner —
~3% narrower than before, which is exactly what was requested.

Author: rhiju

assets/css/style.scss

@@ -736,7 +736,9 @@ details.show-more {
 .site-footer {
   max-width: $container;
   margin: 0.1rem auto 0.4rem;
-  padding: 0 0 0.4rem;
+  /* Match the horizontal padding of .site-main so the footer bars line up
+     under the hero banner's edges to the pixel. */
+  padding: 0 1.25rem 0.4rem;
 }
 
 /* Two-tone bars aligned with the hero banner: dark gradient on the left