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You can choose a theme to alter the appearance of your forms in your flow. provides two one global themes theme : Nouveau or Nouveau Blue. The Nouveau theme gives the forms in your flow a clear (white) background and a submit and cancel button with rounded corners. The Nouveau Blue has the same characteristics of the Nouveau theme and gives the forms in the flow a soft blue background.
Of course, you may create a custom theme instead of using the default themes. After you have added the customized them it will appear in the dropdown list along with the pre-defined options.
Themes applied to forms added to a flow will be overridden by the flow theme. Let's say you had a flow consisting of several forms, each of which used a different theme. Selecting a theme for the flow negates the individual form themes and ensures that the theme selected for the flow is applied to all the forms in the flow. This ensures that the look and feel of all the activities in your flow are the same.