Ionic Datetime color

Hi there,
For my app I used the Ionic Datetime picker. It is working fine so far but now I want to change it’s color and background color but can’t use sass in my app because of dynamic theming.
The fast days I have been looking for a way to change the color via CSS but haven’t found a working way.
Have you got any ideas how to style the Datetime picker with CSS??

Thanks in advance