MathsCalc / app / src / main / res / drawable / shape_key_normal.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <stroke android:width="0.1dp" android:color="@color/green" />
    <solid android:color="@color/trans" />
</shape>