About Lesson
Themes
This app uses a prebuilt theme, which defines the style for most app elements. This is a great time-saver if you create you theme at the beginning so that you’re not styling each individual element.
Once themes are applied to an app, they can be modified or exchanged entirely for a new theme. Custom element styling applied via CSS takes precedence over a theme.
CSS Changes
Whether you’ve applied a theme or not, you can always apply CSS directly to an element (e.g., widget). Applying CSS directly takes precedence over a theme, and in some cases gives you more flexibility and control.