RadioButton changes background color XML

quizapp.xml

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity"
    android:background="@color/main_bg">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <RadioGroup
            android:id="@+id/q1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:orientation="vertical">
<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="18dp"
    android:layout_marginTop="8dp"
    android:layout_marginRight="16dp"
    android:layout_marginLeft="16dp"
    android:layout_marginBottom="8dp"
    android:textStyle="bold"
    android:fontFamily="sans-serif-condensed-medium"
    android:textColor="@color/secondaryTextColor"
    android:text="Question 1:"/>
            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textSize="18dp"
                android:layout_marginTop="8dp"
                android:layout_marginRight="16dp"
                android:layout_marginLeft="16dp"
                android:layout_marginBottom="8dp"
                android:textColor="@color/secondaryTextColor"
                android:fontFamily="sans-serif-condensed-light"
                android:text="What is your name?"/>
            <RadioButton
                android:id="@+id/q1_answer1"
                style="@style/RadioButtonStyle"
                android:onClick="onSelect"
                android:fontFamily="sans-serif-condensed-light"
                android:text="Bob" />

            <RadioButton
                android:id="@+id/q1_answer2"
                style="@style/RadioButtonStyle"
                android:onClick="onSelect"
                android:fontFamily="sans-serif-condensed-light"
                android:text="Billy" />
            <RadioButton
                android:id="@+id/q1_answer3"
                style="@style/RadioButtonStyle"
                android:fontFamily="sans-serif-condensed-light"
                android:onClick="onSelect"
                android:text="Ben" />
            <RadioButton
                android:id="@+id/q1_answer4"
                style="@style/RadioButtonStyle"
                android:onClick="onSelect"
                android:fontFamily="sans-serif-condensed-light"
                android:text="Brian" />
        </RadioGroup>

    </LinearLayout>
</ScrollView>