gecko/mobile/android/base/resources/drawable/awesomebar_tab_unselected.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- This Source Code Form is subject to the terms of the Mozilla Public
   - License, v. 2.0. If a copy of the MPL was not distributed with this
   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->

<level-list xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:maxLevel="0">
        <layer-list>
            <item android:top="@dimen/awesomebar_tab_transparency_height">
                <shape android:shape="rectangle">
                    <solid android:color="#EEF1F5"/>
                </shape>
            </item>
        </layer-list>
    </item>

    <item android:maxLevel="1">
        <layer-list>
            <item android:top="@dimen/awesomebar_tab_transparency_height">
                <shape android:shape="rectangle">
                    <solid android:color="#EEF1F5"/>
                </shape>
            </item>

            <item android:bottom="2dip"
                  android:drawable="@drawable/awesomebar_tab_left"/>
        </layer-list>
    </item>

    <item android:maxLevel="2">
        <layer-list>
            <item android:top="@dimen/awesomebar_tab_transparency_height">
                <shape android:shape="rectangle">
                    <solid android:color="#EEF1F5"/>
                </shape>
            </item>

            <item android:bottom="2dip"
                  android:drawable="@drawable/awesomebar_tab_right"/>
        </layer-list>
    </item>

</level-list>