Jollyness theme provides dark and white style with 6 colors to get you started and you can define unlimited additional color.
Preset begin with "Dark-" prefix will be dark style
Preset begin with "White-" will get white style.
To set default color for the theme by clicking on Presets vertical tab at the left side and choose color in dropdown labeled Default preset
The Preset settings provide the functionality to create your own colors so that you can have full control over the color scheme of your website.