How do you theme the more-info dialog box

I’ve been trying to change the header of the more info dialog box with no success. I’ve tried more-info-header-background regardless of the color it will not change. However, I can change it directly in chrome by modifying the properties.

All help is appreciated.

location attribute
dialog header –secondary-background-color
dialog body –paper-dialog-background-color

Thank you very much,that worked!