style dark dialogs (#864)

app/src/main/java/com/keylesspalace/tusky/AccountActivity.kt

@@ -16,7 +16,6 @@
 package com.keylesspalace.tusky
 
 import android.animation.ArgbEvaluator
-import android.app.AlertDialog
 import android.arch.lifecycle.Observer
 import android.arch.lifecycle.ViewModelProviders
 import android.content.Context
@@ -35,6 +34,7 @@ import android.support.v4.app.Fragment
 import android.support.v4.content.ContextCompat
 import android.support.v4.view.ViewCompat
 import android.support.v4.widget.TextViewCompat
+import android.support.v7.app.AlertDialog
 import android.support.v7.widget.LinearLayoutManager
 import android.view.Menu
 import android.view.MenuItem

app/src/main/res/values-night/styles.xml

@@ -18,6 +18,7 @@
         <item name="android:actionMenuTextColor">@color/text_color_primary_dark</item>
 
         <item name="bottomSheetDialogTheme">@style/AppTheme.BottomSheetDialog.Dark</item>
+        <item name="alertDialogTheme">@style/nightDialogTheme</item>
 
         <item name="window_background">@color/window_background_dark</item>
         <item name="custom_tab_toolbar">@color/custom_tab_toolbar_dark</item>
@@ -85,4 +86,9 @@
         <item name="windowActionBarOverlay">true</item>
     </style>
 
+    <style name="nightDialogTheme" parent="Theme.AppCompat.Dialog.Alert">
+        <item name="android:colorBackground">@color/color_primary_dark_dark</item>
+        <item name="colorAccent">@color/primary</item>
+    </style>
+
 </resources>