:root{font-size:18px}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,sans-serif;line-height:1.5;background:#f7f7f7;color:#111}#app{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:100vh;gap:1.5rem;padding:2rem;text-align:center}#upload-btn{font-size:1.5rem;padding:1.5rem 3rem;border:none;border-radius:1rem;background:#1877f2;color:#fff;cursor:pointer}#status{color:#555}