.modal-dialog-centered {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    /*align-items: center;*/
    min-height: calc(100% - 1rem);
}

    .modal-dialog-centered::before {
        /*display: block;*/
        height: calc(100vh - 1rem);
        content: "";
    }

    .modal-dialog-centered {
        -webkit-box-orient: vertical;
        -webkit-box-direction: normal;
        -ms-flex-direction: column;
        flex-direction: column;
        -webkit-box-pack: center;
        -ms-flex-pack: center;
        /*justify-content: center;*/
        margin-top: 30vh;
        height: 100%;
    }

        .modal-dialog-centered .modal-content {
            max-height: none;
        }

        .modal-dialog-centered::before {
            content: none;
        }



@media (min-width: 576px) {

    .modal-dialog-centered {
        min-height: calc(100% - 2.5rem);
    }
   .modal-dialog-centered::before {
            height: calc(100vh - 2.5rem);
   }
}