Style determines the appearance of the items on a device screen, as well as the device screen itself. You can create new styles for controls, or use any of the predefined styles.
You can choose the colors and font characteristics of the controls.
You can edit existing styles, including the system styles. When you edit a system style, the change is made to all controls using that system style.
When you create new styles, they are applicable only to your current Device Application Designer project, but you can export any styles you create for use in other projects. You can also import external styles for use in your current project.