[Kotlin] how to control every button color with colorPrimary themes.xml at once

1. define the color name with colors.xml

1) res>> values >> colors.xml

2) designate the color

<color name="dark_gray">#636262</color>

 

2.  change the primary color 

1) res>> values> themes> themse.xml

2) i changed purple color into light gray at the primary tag

<item name="colorPrimary">@color/light_gray</item>

 

 

3. confirm the result