A previously healthy 39-year-old man presents to clinic with 3 days of fever, productive cough with green sputum, pleuritic chest pain, and dyspnea. Vitals: T 102.4 F, HR 105, BP 118/72 mm Hg, RR 22, SpO2 94% on room air. Chest examination reveals focal crackles over the right lower lung. He has no comorbidities or recent antibiotic use, and CURB-65 score is 0. Which empiric outpatient antibiotic regimen is most appropriate?