<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="mainBackground">#e0f7fa</color>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>
    <color name="black">#000000</color>
    <color name="transparent_white">#c3ffffff</color>
    <color name="white">#ffffff</color>

</resources>

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="mainBackground">#fafafa</color>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>
    <color name="black">#000000</color>
    <color name="transparent_white">#c3ffffff</color>
    <color name="white">#ffffff</color>

</resources>

Change background color to gray
Change background color to gray

Instead of light blue
