网站“Down for maintenance”最佳实践

I have a public facing website (Banking related) which is due for a PROD update in the next coming weeks. I need to display a "Down for maintenance" page during the outage window.Because the bank has provided me with specific requirements for the page, which needs to be styled exactly the same as the website itself, I dont think the app_offline.htm solution will work for me as I wont be able to access my style sheets and images, because IIS redirect all requests to this page.I have a public facing website (Banking related