Create a color theme for the PreviewScreen UI components #249
Description
The preview screen UI components are much higher contrast than the standard Material color scheme. Currently we don't apply most of the colors based on a color scheme like we have in ToggleButton, which uses the MaterialTheme.
We should define and use a color scheme for the Preview Screen components which use the white / yellow colors we are using now.
We may also want to fix this color scheme to use dark mode for highest contrast.