@media (max-width: 576px) {
    h1 {
        font-size: 25px;
        margin:0 20px;
    }
    .btn {
        font-size: 25px !important;
        width:70px;
        height:70px;
        border-radius: 5px;
        margin:50px 0px;
    }
    .img-u {
        margin:50px 25px;
        width:70px;
        height:70px;
    }
}

@media (max-width: 768px) {

}

@media (max-width: 992px) {

}

@media (max-width: 1200px) {

}