You can set your site colors using the Gecko Customizer -> within the Global color category, in order to apply them across your entire site.
Primary colors #
Base colors are used for important elements like action buttons, alerts, progress bars, or active element indicators.
Alt colors #
Alternative to primary color. Default color for community ‘Join button’, one of the Gradient colors and some small UI elements.
Gradient colors #
Used as default gradient widget colors. (maybe on more elements in the future)
Info colors #
Info colors are used for default alerts.