ThingWorx uses Style Definitions to set the size, color, and style of the font, the background, foreground, and line color of the widget, and the image (stored as a Media Entity) for a particular mashup widget. Style definitions can also be used to define an aspect of that widget. For example, the style to be applied when the mouse hovers over a widget.

In ThingWorx Utilities, the out-of-the-box style definitions are located in the PTC.Core namespace. Any style definition that is part of the ThingWorx Utilities Styles Extension can be updated to change the way widgets are displayed in the mashup. For example, if the PTC.Core.ButtonStyle is changed , all buttons that reference this style definition are changed.

It is recommended that you create new style definitions when building an extension with new mashups and want to style a particular widget in the mashup. Each widget allows various aspects of each widget to be changed. Those styling aspects can be changed to reference an existing style definition or to define a custom in-line style.