The SpreadsheetControl allows you to customize the appearance of its elements using themes and templates. A theme uses a styling and theming mechanism exposed by WPF that provides you with centralized control over the appearance of the entire application. A template can provide a completely different look and feel for Spreadsheet visual elements (cells).
The Spreadsheet control supports standard DevExpress theming. The List of DevExpress WPF Themes document lists the available themes and contains a XAML sample that illustrates how to apply a desired theme.
You can also select different templates for different cells based on custom logic. Use the SpreadsheetControl.CellTemplateSelector property to specify a template selector - a class that chooses a template if a required condition is met.