A 19-year-old university student presents with a 2-day history of fever, pleuritic chest pain and productive cough with green sputum. She is otherwise healthy and not pregnant. Her temperature is 38.5°C, respiratory rate 20 breaths/min, heart rate 96 beats/min, blood pressure 118/72 mmHg and SpO₂ 97% on room air. CURB-65 score is 0. What is the most appropriate empirical antibiotic regimen in general practice according to Therapeutic Guidelines for mild community-acquired pneumonia?