.modal-backdrop {
    background-color: rgba(0, 0, 0, 0.9) !important;
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    width: 100% !important;
    height: 100% !important;
    z-index: 1040 !important;
    margin: 0 !important;
    padding: 0 !important;
}