This component is not an option for the dark mode theme as the contrast will even change the colors of the images and it does not use theme variables but rather a filter for contrast - you will not be able to choose the specific color to change but rather the level of contrast you want. 

This is useful if your CSS is not following best practice with variables, it works in the Layout class and with an additional color variable for the body background, the color of the body can be chosen, and so you can have more control of the background color you want. 

You can adapt the contrast filter to what you need in terms of accessibility.