fixed popup menu in dark theme

src/main/res/layout/toolbar.xml

@@ -4,8 +4,8 @@
     android:layout_height="wrap_content"
     android:background="?attr/colorPrimary"
     android:minHeight="?attr/actionBarSize"
-    android:elevation="6dp"
+    android:elevation="4dp"
     android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
-    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
+    app:popupTheme="?popupOverlayStyle"
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto" />

src/main/res/values/attrs.xml

@@ -71,4 +71,6 @@
         <attr name="backgroundColor" format="reference|color"/>
     </declare-styleable>
 
+    <attr name="popupOverlayStyle" format="reference"/>
+
 </resources>

src/main/res/values/themes.xml

@@ -5,6 +5,7 @@
         <item name="colorPrimary">@color/primary500</item>
         <item name="colorPrimaryDark">@color/primary700</item>
         <item name="colorAccent">@color/accent</item>
+        <item name="popupOverlayStyle">@style/ThemeOverlay.AppCompat.Light</item>
 
         <item name="color_background_primary">@color/grey50</item>
         <item name="color_background_secondary">@color/grey200</item>
@@ -81,7 +82,7 @@
         <item name="colorPrimary">@color/primary800</item>
         <item name="colorPrimaryDark">@color/primary900</item>
         <item name="colorAccent">@color/accent</item>
-
+        <item name="popupOverlayStyle">@style/ThemeOverlay.AppCompat.Dark</item>
 
         <item name="color_background_primary">@color/grey800</item>
         <item name="color_background_secondary">@color/grey900</item>