feat: UX

frontend/src/components/Header.tsx

@@ -0,0 +1,24 @@
+import { Calendar } from 'lucide-react';
+
+export const Header = () => {
+  return (
+    <header className="border-b border-border bg-card/50 backdrop-blur-sm sticky top-0 z-50">
+      <div className="container max-w-5xl mx-auto px-4 py-4 flex items-center justify-between">
+        <div className="flex items-center gap-3">
+          <div className="w-10 h-10 rounded-xl bg-primary flex items-center justify-center">
+            <Calendar className="w-5 h-5 text-primary-foreground" />
+          </div>
+          <div>
+            <h1 className="font-semibold text-foreground text-lg">Monadical</h1>
+            <p className="text-xs text-muted-foreground">Calendar Coordination</p>
+          </div>
+        </div>
+        <div className="flex items-center gap-2">
+          <div className="w-8 h-8 rounded-full bg-primary/10 flex items-center justify-center text-sm font-medium text-primary">
+            AR
+          </div>
+        </div>
+      </div>
+    </header>
+  );
+};