body {
    font-family: "SimSun","STSong",serif;
    background: #fff9f0 url('https://i.imgur.com/3m5yFqk.png') no-repeat center top;
    background-size: cover;
    margin:0; padding:0;
}
.container { max-width: 480px; margin: 0 auto; padding: 20px; }
h1 { text-align:center; color:#a52a2a; }
.subtitle { text-align:center; color:#5a2e2e; margin-bottom: 20px; font-style: italic; }
.form label { display:block; margin:10px 0; }
button { display:block; width:100%; padding:10px; background:#a52a2a; color:#fff; border:none; cursor:pointer; }
.result { margin-top:20px; padding:15px; border:1px solid #a52a2a; background:#fff3e0; min-height:80px; }