body{font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica Neue,Arial;margin:0;padding:0}.container{max-width:900px;margin:48px auto;padding:0 16px}header{margin-bottom:24px}.card{background:#fff;border-radius:8px;padding:16px;box-shadow:0 2px 8px #0000000f}button{background:#0ea5a4;color:#fff;border:none;padding:8px 12px;border-radius:6px;cursor:pointer}