add mobile device detection and redirect to external site

src/utils/deviceDetection.ts

@@ -0,0 +1,21 @@
+function isPortraitAndNarrow(): boolean {
+  return window.innerWidth < window.innerHeight && window.innerWidth < 768;
+}
+
+export function isMobileDevice(): boolean {
+  const toMatch = [
+    /Android/i,
+    /webOS/i,
+    /iPhone/i,
+    /iPad/i,
+    /iPod/i,
+    /BlackBerry/i,
+    /Windows Phone/i
+  ];
+
+  const isMobileUserAgent = toMatch.some((toMatchItem) => {
+    return navigator.userAgent.match(toMatchItem);
+  });
+
+  return isMobileUserAgent || isPortraitAndNarrow();
+}