error.logcat

Build version: nine hundred ninety nine
Device: Nexus 6P (angler) [google/angler/angler:8.1.0/OPM6.171019.030.E1/4805388:user/release-keys]
ROM: 8.1.0 - Unknown
Theme system: OMS (andromeda)

Stack trace:
java.lang.RuntimeException: Unable to start activity ComponentInfo{projekt.substratum/projekt.substratum.MainActivity}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2778)
	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
	at android.app.ActivityThread.-wrap11(Unknown Source:0)
	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
	at android.os.Handler.dispatchMessage(Handler.java:106)
	at android.os.Looper.loop(Looper.java:164)
	at android.app.ActivityThread.main(ActivityThread.java:6494)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
	at android.support.v7.app.AppCompatDelegateImplV9.createSubDecor(AppCompatDelegateImplV9.java:354)
	at android.support.v7.app.AppCompatDelegateImplV9.ensureSubDecor(AppCompatDelegateImplV9.java:323)
	at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:284)
	at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139)
	at android.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:303)
	at android.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:284)
	at projekt.substratum.MainActivity.onCreate(MainActivity.java:263)
	at android.app.Activity.performCreate(Activity.java:7009)
	at android.app.Activity.performCreate(Activity.java:7000)
	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2731)
	... 9 more


User actions:
2018-08-10 10:53:55: SplashScreenActivity created
2018-08-10 10:53:56: SplashScreenActivity resumed
2018-08-10 10:53:56: SplashScreenActivity paused
2018-08-10 10:53:56: MainActivity created