body{font-family:Arial,sans-serif;background:#f5f7fb;margin:0;color:#333}header{background:#0f766e;color:#fff;padding:24px;text-align:center}main{max-width:900px;margin:24px auto;padding:0 16px}.card{background:#fff;border-radius:12px;padding:24px;box-shadow:0 2px 8px rgba(0,0,0,.08);margin-bottom:20px}a.btn{display:inline-block;background:#0f766e;color:#fff;text-decoration:none;padding:10px 16px;border-radius:8px;margin:6px}footer{text-align:center;padding:20px;color:#666}h2{color:#0f766e}@media(max-width:600px){header{padding:18px}.card{padding:16px}}