Handling "Page not found (404)"
Currently an attempt to access a deep link, e.g., https://gracedb-playground.ligo.org/superevents/S181203f/view/, without an active login session returns 404 "Page not found" and the message "No Superevent matches the given query."
Please consider enhancing the 404 page to conditionally indicate (if there is no active Shibboleth session) that authorized users should first try logging in, and provide a login hyperlink to do so.
For bonus points, see if there is an easy way for users that select the login link (and successfully authenticate) to automatically have their browsers reload the originally requested page.
Note, for users with a valid Shibboleth session and still land at a URL with no valid page, please also consider changing messages like No Superevent matches the given query." to "No Superevent matches the given query or you are not authorizes to view it."