.center {
    margin: 0;
    position: absolute;
    top: 50%;
    max-height: 100px;
    left: 50%;
    margin-right: -50%;
    transform: translate(-50%, -50%);
}

.bottom_center {
    margin: 0;
    position: absolute;
    top: 90%;
    max-height: 200px;
    left: 50%;
    margin-right: -50%;
    background: transparent;
    transform: translate(-50%, -50%);
}