Modern university professor, middle-aged man, bespectacled, gray hair, formal attire, standing in front of a green screen, holding a marker, pointing at a diagram of sustainable building, lecture hall, bright lighting, wooden desks, students taking notes, architectural models on shelves, plants on tables, natural materials, eco-friendly, recyclable, minimal waste, renewable energy, solar panels, green roofs, vertical gardens, urban planning, eco-city, futuristic, innovative, 3/4 composition, shallow depth of field.