Unify section spacing rhythm

components/section-heading.tsx

@@ -11,16 +11,19 @@ export function SectionHeading({
   description,
   align = "left",
 }: SectionHeadingProps) {
-  const alignment = align === "center" ? "mx-auto max-w-3xl text-center" : "max-w-3xl";
+  const alignment =
+    align === "center"
+      ? "section-heading-stack mx-auto max-w-3xl text-center"
+      : "section-heading-stack max-w-3xl";
 
   return (
     <div className={alignment}>
       <p className="section-kicker">{eyebrow}</p>
-      <h2 className="type-section-title mt-4 text-[var(--color-ink)]">
+      <h2 className="type-section-title text-[var(--color-ink)]">
         {title}
       </h2>
       {description ? (
-        <p className="type-body-responsive mt-5 text-[var(--color-muted)]">{description}</p>
+        <p className="type-body-responsive text-[var(--color-muted)]">{description}</p>
       ) : null}
     </div>
   );