body{font-family:Arial;background:#eef2f7}#app{max-width:760px;margin:30px auto;background:#fff;padding:25px;border-radius:12px}
button{padding:10px 20px;font-size:18px}.o{border:2px solid #ddd;padding:12px;border-radius:8px;margin:10px 0;cursor:pointer}.good{background:#d8ffd8}.bad{background:#ffd6d6}