A framework has been developed as a basis for design and implementation of adaptive Web systems. This framework and the respective architecture support the idea of high-level synthesis and facilitate different types of adaptation. In this paper, we describe main components in the framework, and introduce an example application from e-News domain, a personalized electronic news system (PENS). PENS is implemented as the proof of concept and to demonstrate how Web pages are synthesized with different attributes from the same description, and to show adaptation based on users? behavior and client-side characteristics.