Refactor footer layout and styling for improved structure

Reorganize footer HTML with consistent spacing, refined typography, and
separated copyright/powered-by section. Add footer column layout CSS
with
constrained brand column width and padding adjustments.

assets/css/custom.css

@@ -172,3 +172,16 @@ figcaption.post-caption {
     grid-template-columns: repeat(3, minmax(0, 1fr));
   }
 }
+
+/* Footer brand column — extra breathing room */
+.footer-brand .hx\:whitespace-pre-line {
+  max-width: 18rem;
+}
+.footer-nav {
+  padding-left: 1rem;
+  padding-right: 1rem;
+}
+.footer-links {
+  padding-left: 2rem;
+}
+.footer-roadmap { padding: 1rem; }