res/values/styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!-- IME -->
    <style name="Keyboard">
        <item name="fontFamily">sans-serif</item>
        <item name="textStyle">normal</item>
        <item name="keyTextSize">@dimen/keyboard_key_letter_height</item>
        <item name="labelTextSize">@dimen/keyboard_key_letter_height</item>
        <item name="keyTextColorPrimary">?android:attr/textColorPrimary</item>
        <item name="keyTextColorSecondary">?android:attr/textColorSecondary</item>
        <item name="keyBackground">@drawable/keyboard_key_background</item>
    </style>
</resources>