PreferenceActivity and Appcompat, how to connect correctly?

Question

Android

In general, the situation is this, the application uses appcompat and in almost all "corners" of the application everything is displayed adequately, except for the settings menu. I tried to set it up on my own, but it didn't work. I didn't make a toolbar, because it caused a lot of problems.
Here are the sources of the "settings": https://github.com/RadiationX/4pdaClient-plus/tree...
The main file from which "other files are inherited " is BasePreferencesActivity.java . most of the file is underlined in red, after some fixes it looks like this:


I ask for help, I coped with almost all the problems in the application. Other than that, I really don't know what to do here.