main.css

body {
    font-family: "Microsoft YaHei", Arial, Helvetica, sans-serif;
}

main {
    width: 455px;
    height: 450px;
    background: #000;
    margin: 60px auto;
    padding: 5px 0 0 6px;
}

main button {
    margin: 5px;
    width: 140px;
    height: 138px;
    float: left;
    font-size: 80px;
    font-family: "Microsoft YaHei", Arial;
}

.mask {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: rgba(30, 30, 30, 0.6);
}

.select {
    width: 600px;
    height: 250px;
    background: #000;
    padding: 10px;
    margin: 130px auto;
    border-radius: 20px;
    color: #fff;
}

@media only screen and (max-width: 50em) {
    .select {
        width: 70%;
    }
}

div input {
    float: left;
    margin-top: 30px;
    margin-left: 30%;
    border-radius: 5px;
    width: 40px;
    height: 40px;
    font-size: 30px;
    font-family: "Microsoft YaHei", Arial;
}

p {
    text-align: center;
    width: 300px;
    margin: 20px auto 40px;
    line-height: 40px;
}