Background Color is not 100 percent white !!!

[EhsanSetayesh]

hi .
when I change background color to white on smarttablayout actually its not 100 percent white its light very brown but for other colors has not problem just for white please help me

<com.ogaclejapan.smarttablayout.SmartTabLayout
android:id="@+id/smart"
android:layout_width="match_parent"
android:layout_height="55dp"
android:background="#ffffff"
app:stl_dividerThickness="0dp"
app:stl_defaultTabBackground="@color/transparent"
app:stl_customTabTextLayoutId="@layout/custom_tab"
app:stl_defaultTabTextColor="@color/black1"
app:stl_defaultTabTextHorizontalPadding="24dp"
app:stl_indicatorColor="@color/purple1"
app:stl_indicatorCornerRadius="1.5dp"
app:stl_indicatorInterpolation="linear"
app:stl_indicatorThickness="3dp"
app:stl_distributeEvenly ="false"
app:stl_underlineColor="@android:color/transparent"
/>