Use accent color for dark + dark grey theme

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

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+
+  <style name="DarkGrey" parent="DarkGrey_Base">
+    <item name="buttonBarPositiveButtonStyle">@style/AlertButtonStyle</item>
+    <item name="buttonBarNegativeButtonStyle">@style/AlertButtonStyle</item>
+    <item name="buttonBarNeutralButtonStyle">@style/AlertButtonStyle</item>
+    <item name="materialButtonText">@color/button_accent_text</item>
+    <item name="materialButtonBackground">@color/button_accent_background</item>
+    <item name="materialButtonRipple">@color/button_accent_ripple</item>
+    <item name="materialButtonStroke">@color/button_accent_stroke</item>
+    <item name="weekdayButtonBackground">?attr/colorAccent</item>
+    <item name="weekdayButtonText">?attr/colorOnSecondary</item>
+  </style>
+
+</resources>

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

@@ -159,4 +159,8 @@
     <item name="rippleColor">?attr/materialButtonRipple</item>
   </style>
 
+  <style name="AlertButtonStyle" parent="Widget.MaterialComponents.Button.TextButton.Dialog.Flush">
+    <item name="android:textColor">?attr/colorAccent</item>
+  </style>
+
 </resources>

app/src/main/res/values/theme_dark_grey.xml

@@ -1,9 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
 
-  <style name="DarkGrey" parent="WhiteToolbarTheme">
+  <style name="DarkGrey_Base" parent="WhiteToolbarTheme">
     <item name="colorPrimary">@color/grey_900</item>
     <item name="colorPrimaryVariant">@color/grey_statusbar</item>
   </style>
 
+  <style name="DarkGrey" parent="DarkGrey_Base"/>
+
 </resources>

app/src/main/res/values/theme_white.xml

@@ -18,8 +18,4 @@
     <item name="weekdayButtonText">?attr/colorOnSecondary</item>
   </style>
 
-  <style name="AlertButtonStyle" parent="Widget.MaterialComponents.Button.TextButton.Dialog.Flush">
-    <item name="android:textColor">?attr/colorAccent</item>
-  </style>
-
 </resources>