refactor: reduce top margin in Nodes CallToAction CTA section

- Changed top margin from mt-10 to mt-6 for CTA cards container for tighter spacing

src/pages/nodes/CallToAction.tsx

@@ -45,7 +45,7 @@ export function CallToAction() {
               while expanding the sovereign digital grid.
             </p>
 
-            <div className="mt-10 flex flex-wrap justify-center gap-x-10 gap-y-8">
+            <div className="mt-6 flex flex-wrap justify-center gap-x-10 gap-y-8">
               <div className="flex flex-col items-center text-center max-w-xs">
                 <Button to="/host" variant="solid" color="cyan" className="mt-4">
                   Join Mycelium