How to setup RouterOS as simple Webserver?

I want to use a RouterOS-Device (RouterBoard or x86) as small Webserver for a small, static website.

Since both, WebFig and Hotspot are Webserved applications,
I assume that there is a method to create a simple webserver, that is reachable from all interfaces and subnets.
But how can this be done?

Unfortunately not - MT is a router OS not a webserver