Summary

In this chapter, we learned a lot about widgets, themes, and styles in general. These are essential ingredients for creating themeable user interfaces. Widgets are the structural components that user interfaces are made of. Styles change the look and feel of widgets in addition to the layout of the widget elements.

Adding styles to widgets presents problems with consistency and portability. We've seen different ways we can improve our CSS so that we can avoid duplicate property definitions by grouping selectors. We can further increase style reuse by moving CSS properties to a base class and nesting more specific properties within it.