feat: rebuild marketing site with full component suite and preview

marketing-site/components/Book3D.jsx

@@ -0,0 +1,35 @@
+/**
+ * Pure-CSS 3D book styled as the field guide. Decorative, so aria-hidden.
+ * Faces (cover / spine / fore-edge / top / back) are assembled with
+ * transform-style: preserve-3d; see `.book3d` in globals.css.
+ */
+export default function Book3D() {
+  return (
+    <div className="book3d" aria-hidden="true">
+      <div className="book3d__inner">
+        <div className="book3d__face book3d__back" />
+        <div className="book3d__face book3d__pages" />
+        <div className="book3d__face book3d__top" />
+        <div className="book3d__face book3d__spine">
+          <span>AIBook.fun · Responsible Agentic AI</span>
+        </div>
+        <div className="book3d__face book3d__cover">
+          <span className="book3d__kicker">The Field Guide</span>
+          <h3 className="book3d__title">
+            Responsible
+            <br />
+            Agentic AI
+          </h3>
+          <span className="book3d__line" />
+          <span className="book3d__sub">Tested workflows you can actually run</span>
+          <svg className="book3d__mark" viewBox="0 0 40 40" fill="none">
+            <circle cx="20" cy="20" r="17.5" stroke="#efe9db" strokeWidth="1" opacity="0.7" />
+            <path d="M20 5 L22.6 20 L20 35 L17.4 20 Z" fill="#efe9db" />
+            <path d="M5 20 L20 17.4 L35 20 L20 22.6 Z" fill="#efe9db" opacity="0.55" />
+          </svg>
+          <span className="book3d__brand">AIBook.fun</span>
+        </div>
+      </div>
+    </div>
+  );
+}