To apply a color that cascades across your entire event experience, visit the admin site for your event, navigate to Event Setup. Here you'll find Color Theme.
Applying a Custom Color
You may select from any of the pre-defined color recommendations from Cadence or enter your own custom color. With the custom color field, you may use your cursor to move around finding the ideal color for your event or you may enter a custom color code.
Uploading an Image or Logo into a Color Picker
You may often not know the specific color value to apply. A neat trick we often do is visit https://imagecolorpicker.com/en/ to upload an image or logo to detect the color value used in the image or logo.
Here's an explainer video: