body{font:16px system-ui,sans-serif;background:#f5f6f8;color:#202531;margin:0;min-height:100vh;display:grid;place-items:center}
main{background:white;padding:2rem;width:min(22rem,90vw);border:1px solid #d6dae0;border-radius:.7rem}
label{display:block;margin:1rem 0}input{display:block;width:100%;box-sizing:border-box;padding:.6rem;margin-top:.3rem}
button{padding:.7rem 1rem}#thong-bao{color:#a32222;min-height:1.5rem}