.step_area:nth-child(1){
    margin-top: 5%;
}
.step_area{
    margin-top: 0;
}
.step{
    width: 80%;
    margin: 0 auto;
}
.QRcode{
    width: 50%;
    margin: 3% auto;
}
.arrow{
    width: 7%;
    margin: 1% auto 5%;
    transform: rotate(90deg);
}
.arrow.mb{
    display: block;
}   
@media screen and (min-width:769px) {
    .step_area:nth-child(1){
        margin-top: 2%;
    }
    .step_area{
        display: flex;
        align-items: center;
        margin-top: 1%;
    }
    .step{
        width: 14%;
        margin: 0;
    }
    .QRcode{
        width: 12%;
        margin-left: 2%;
    }
    .arrow{
        width: 2%;
        margin: 0 1%;
        transform: rotate(0deg);
    }
    .arrow.mb{
        display: none;
    }   
}