Drupal 8 allows for the configuration of theme-specific settings. These can vary based on the theme and the amount of extensibility that a theme provides. For example, if we click on the Bartik theme, we will notice that it provides us with an ability to change the COLOR SCHEME through a series of presets, as shown in the following image:

Feel free to experiment by selecting various color sets and then previewing what those selections would look like if applied. Outside the core themes shipped with Drupal 8, we can apply prebuilt themes to provide various features.