refactor: update button colors in CallToAction and Hero components for improved contrast

- Changed link button color from cyan to white in agents, home, and network CallToAction components
- Updated network Hero secondary button from dark to gray outline variant

src/pages/agents/CallToAction.tsx

@@ -69,7 +69,7 @@ export function CallToAction() {
                 as="a"
                 to="https://threefold.info/mycelium_network/docs/"
                 variant="link"
-                color="cyan"
+                color="white"
                 className="inline-flex items-center gap-1.5"
                 target="_blank"
                 rel="noopener noreferrer"

src/pages/home/CallToAction.tsx

@@ -66,7 +66,7 @@ export function CallToAction() {
                 Deploy in Cloud
               </Button>
 
-              <Button to="/nodes" variant="link" color="cyan">
+              <Button to="/nodes" variant="link" color="white">
                 Host a Node &rarr;
               </Button>
             </div>

src/pages/network/CallToAction.tsx

@@ -65,7 +65,7 @@ Use the network to link environments, deploy workloads, or host nodes to strengt
                 Deploy in Cloud
               </Button>
 
-              <Button to="/nodes" variant="link" color="cyan">
+              <Button to="/nodes" variant="link" color="white">
                 Host a Node &rarr;
               </Button>
             </div>

src/pages/network/Hero.tsx

@@ -100,7 +100,7 @@ export function Hero() {
                 as="a"
                 to="https://threefold.info/mycelium_network/docs/"
                 variant="outline"
-                color="dark"
+                color="gray"
                 target="_blank"
                 rel="noopener noreferrer"
               >