feat: implement the first version of landing page

frontend/src/components/landing/section.tsx

@@ -0,0 +1,29 @@
+import { cn } from "@/lib/utils";
+
+export function Section({
+  className,
+  title,
+  subtitle,
+  children,
+}: {
+  className?: string;
+  title: React.ReactNode;
+  subtitle?: React.ReactNode;
+  children: React.ReactNode;
+}) {
+  return (
+    <section className={cn("mx-auto flex flex-col py-16", className)}>
+      <header className="flex flex-col items-center justify-between">
+        <div className="mb-4 bg-linear-to-r from-white via-gray-200 to-gray-400 bg-clip-text text-center text-5xl font-bold text-transparent">
+          {title}
+        </div>
+        {subtitle && (
+          <div className="text-muted-foreground text-center text-xl">
+            {subtitle}
+          </div>
+        )}
+      </header>
+      <main className="mt-4">{children}</main>
+    </section>
+  );
+}