Update selected_box colors for dark theme

app/src/main/res/drawable/selected_box.xml

@@ -19,6 +19,6 @@
   -->
 
 <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >
-    <solid android:color="@color/grey_100" />
+    <solid android:color="?highlightedBackgroundColor" />
     <stroke android:width="2dip" android:color="@color/grey_500"/>
 </shape>

app/src/main/res/values-v21/styles.xml

@@ -32,6 +32,7 @@
         <item name="cardBackgroundColor">@color/white</item>
         <item name="windowBackgroundColor">@color/grey_200</item>
         <item name="headerBackgroundColor">@color/grey_200</item>
+        <item name="highlightedBackgroundColor">@color/grey_100</item>
 
         <item name="android:textColor">#606060</item>
         <item name="fadedTextColor">@color/grey_600</item>
@@ -53,6 +54,7 @@
         <item name="cardBackgroundColor">@color/grey_800</item>
         <item name="windowBackgroundColor">@color/grey_850</item>
         <item name="headerBackgroundColor">@color/grey_900</item>
+        <item name="highlightedBackgroundColor">@color/grey_800</item>
 
         <item name="android:textColor">@color/grey_50</item>
         <item name="fadedTextColor">@color/grey_500</item>

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

@@ -25,6 +25,7 @@
     <attr name="headerBackgroundColor" format="reference"/>
     <attr name="secondaryTextColor" format="reference"/>
     <attr name="inactiveCheckmarkColor" format="reference"/>
+    <attr name="highlightedBackgroundColor" format="reference"/>
     <attr name="palette" format="reference"/>
 
 </resources>