Change shadow color of ViewPager

This color is usually the same as the accent, look in the res folder, in the styles file, if it does not, add these lines:

 <style name="AppTheme" parent="android:Theme.Material">
    <!-- Main theme colors -->

    <item name="android:colorPrimary">@color/primary</item>

    <item name="android:colorPrimaryDark">@color/primary_dark</item>

    <item name="android:colorAccent">@color/accent</item>
  </style>

The "colorAccent" are these secondary colors of selection, where @color/accent you can change to the color you want ex black: #000

After this, just put this theme in your manifest activity:

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@android:style/AppTheme" >
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

The other two colors of style are the color of your toolbar and the color of the top, where it shows battery, time etc of the cell, you also arrow them of your preference in the theme.

Multi-color site: link