Systems for creating and rendering skins are described. In one described embodiment, a system is configured to provide multiple skin elements that comprise part of a user interface and synchronize a property of at least a first of the skin elements with a property of a second of the skin elements such that a change in the property of the second of the elements causes a change in the property of the first of the elements. The system synchronizes properties by describing synchronization between the properties using an XML data structure.