Revert "slice 4: accent palette refinement — blue → teal"

This reverts commit 52fe7bceb6.

src/app/error.tsx

@@ -25,13 +25,13 @@ export default function Error({
         <div className="flex gap-3 justify-center">
           <button
             onClick={() => reset()}
-            className="px-4 py-2 bg-[#5B7C8D] text-white text-sm rounded-sm hover:bg-[#4A6473] transition-colors"
+            className="px-4 py-2 bg-[#3b82f6] text-white text-sm rounded-sm hover:bg-[#2563eb] transition-colors"
           >
             Try again
           </button>
           <Link
             href="/home-page"
-            className="px-4 py-2 border border-[#333] text-sm rounded-sm hover:border-[#5B7C8D] transition-colors"
+            className="px-4 py-2 border border-[#333] text-sm rounded-sm hover:border-[#3b82f6] transition-colors"
           >
             Home
           </Link>