Adaptive Learning Progress Tracker Interface

Create an advanced CSS-based progress tracking interface for personalized student learning journeys. Develop a modular, animated visualization that displays learning milestones, skill acquisition percentages, and adaptive difficulty progression. Implement CSS custom properties for dynamic theming, supporting both light and dark modes with smooth transitions. The design must be fully responsive, with SVG-based iconography that scales perfectly across devices and provides clear, intuitive feedback about learning achievements.