Site: SEO pass (titles, share image, structured data, FAQ, 404)

docs/404.html

@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="UTF-8">
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+<title>Page not found | EDNexus</title>
+<meta name="robots" content="noindex">
+<meta name="theme-color" content="#0E1013">
+<link rel="icon" type="image/svg+xml" href="/EDNexus/assets/logo/ednexus-icon.svg">
+<style>
+  body { margin: 0; min-height: 100vh; display: grid; place-items: center; background: #0E1013; color: #E7E9EE;
+         font-family: "Segoe UI", Inter, Arial, sans-serif; text-align: center; padding: 24px; }
+  h1 { margin: 0 0 8px; }
+  p { color: #8A909C; margin: 0 0 24px; }
+  a { color: #FF8C2E; }
+</style>
+</head>
+<body>
+<main>
+  <h1>That page is not here</h1>
+  <p>The page you were looking for does not exist or has moved.</p>
+  <p><a href="/EDNexus/">Back to the EDNexus homepage</a> &middot; <a href="https://github.com/Signal-Thread/EDNexus">EDNexus on GitHub</a></p>
+</main>
+</body>
+</html>

docs/sitemap.xml

@@ -2,6 +2,7 @@
 <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
   <url>
     <loc>https://signal-thread.github.io/EDNexus/</loc>
+    <lastmod>2026-10-09</lastmod>
     <changefreq>weekly</changefreq>
     <priority>1.0</priority>
   </url>