You can create themes that customize only the device UI lock screen or Home screen, or lots of screens with as many or as few customized UI elements that fit your needs.
You can affect the look of many, many discrete elements (such as buttons, icons, text, and title bars) in the UI screens of supported devices. Each UI element is typically controlled by several UI aspects (such as the text color and background color of a button).
In Theme Editor, you control UI aspects that control the look of their associated UI elements.
One Theme Editor parameter (such as Text color) controls one UI aspect, which typically affects several UI elements in 1 or more UI screens (such as 20⁰ and London text below).
Several UI aspects typically affect each UI element (such as the date displayed below).
Different theme parameters can affect different UI elements or the same UI element. When multiple theme parameters control the same UI element, each parameter can be in the same or a different Theme Editor cluster, subgroup, or group.
Additionally, one parameter can set another parameter (linked parameters). Initially, the child-linked parameter has the same setting as its parent, but you can set the child to a different setting.