.step-flex {
    display: flex;
    align-items: center;
    justify-content: center
}

.step-flex img {
    padding: 0;
    width: 300px
}

@media(max-width:600px) {
    .step-flex img {
        width: 200px;
        height: 250px
    }
}

@media(max-width:450px) {
    .step-flex img {
        width: 150px;
        height: 200px
    }
}