body {
    padding: 0;
    margin: 0;
    background-color: #f1f3f2;
}

.son {
    position: absolute
}

.dad {
    position: relative
}

.no-select {
    -webkit-user-select: none; /* Chrome, Safari, Opera */
    -moz-user-select: none;    /* Firefox */
    -ms-user-select: none;     /* Internet Explorer/Edge */
    user-select: none;         /* 非前缀版本, 工作在大多数浏览器 */
}




.content {
    display: -webkit-flex;
    display: flex;
    -webkit-align-items: center;
    -moz-align-items: center;
    -ms-align-items: center;
    -o-align-items: center;
    align-items: center;
    -webkit-justify-content: center;
    -moz-justify-content: center;
    -ms-justify-content: center;
    -o-justify-content: center;
    justify-content: center;
}

.content-row {
    display: flex;
    justify-content: space-evenly;
    flex-wrap: wrap;
}

input {
    border: none;
}

input:focus {
    outline: none;
}

button {
    border: none;
}

.open {
    position: absolute;
    width: 100%;
    height: 100%;
}


a {
    text-decoration: none;
    color:#fff;
}