Document

Represents a document with a hierarchical structure of elements, styles, and layout capabilities. The Document class manages the layout and styling system by utilizing a Layouter and an observable list of stylesheets.

Features include:

• The ability to manage styles through a list of StyleSheet objects.

• Automatic tracking of changes to stylesheets to ensure layout updates are performed when necessary.

• Support for laying out the document body based on computed styles from the provided stylesheets.

• A controllable lifecycle to clean up resources when the document is no longer in use.

Implements AutoCloseable to ensure that resources such as controlManager, styleSheets, and body are cleaned up appropriately.