Multiple Web Config Files

Question

So, I have an application that needs multiple Webconfigs. I seperated each Web form in its own folder and put a web config file.

How do I make sure that Login Webform only uses the LoginWeb.Config?

This is my root Web Config and that is what it's using.

I've done searches, and the closest thing I came too was this in my LoginWeb.config file

<appSettings>
    <add key="theme" value="Login theme"/>
  </appSettings>

No idea how to link that to my Login.aspx web form so it can use that specific config file. Help would be appreciated.