Changing Slider-Color does not affect mobile-view

Hey *,   Changing "Slider Content Color" and "Slider Text Color" to white, the normal, the desktop view looks as wanted. Content and Text is white. Opening the page on a mobile phone or using f12 for emulating, the Content and Text has a different color. What am I doing wrong? I am using the "light" Version of the theme with customized colors.   Thanks and kind regards Heiko