diff --git a/404.html b/404.html
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+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8" />
+    <title>Single Page Apps for GitHub Pages</title>
+    <script type="text/javascript">
+      // Single Page Apps for GitHub Pages
+      // MIT License
+      // https://github.com/rafgraph/spa-github-pages
+      // This script takes the current url and converts the path and query
+      // string into just a query string, and then redirects the browser
+      // to the new url with only a query string and hash fragment,
+      // e.g. https://www.foo.tld/one/two?a=b&c=d#qwe, becomes
+      // https://www.foo.tld/?/one/two&a=b~and~c=d#qwe
+      // Note: this 404.html file must be at least 512 bytes for it to work
+      // with Internet Explorer (it is currently > 512 bytes)
+
+      // If you're creating a Project Pages site and NOT using a custom domain,
+      // then set pathSegmentsToKeep to 1 (enterprise users may need to set it to > 1).
+      // This way the code will only replace the route part of the path, and not
+      // the real directory in which the app resides, for example:
+      // https://username.github.io/repo-name/one/two?a=b&c=d#qwe becomes
+      // https://username.github.io/repo-name/?/one/two&a=b~and~c=d#qwe
+      // Otherwise, leave pathSegmentsToKeep as 0.
+
+      var isPrPreview = window.location.pathname.includes('/pr-preview/');
+      var pathSegmentsToKeep = isPrPreview ? 4 : 0;
+
+      var l = window.location;
+      l.replace(
+        l.protocol +
+          '//' +
+          l.hostname +
+          (l.port ? ':' + l.port : '') +
+          l.pathname
+            .split('/')
+            .slice(0, 1 + pathSegmentsToKeep)
+            .join('/') +
+          '/?/' +
+          l.pathname.slice(1).split('/').slice(pathSegmentsToKeep).join('/').replace(/&/g, '~and~') +
+          (l.search ? '&' + l.search.slice(1).replace(/&/g, '~and~') : '') +
+          l.hash
+      );
+    </script>
+  </head>
+  <body></body>
+</html>
