.popunder-aniversario {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 99999;
    background: rgba(0,0,0,0.5);
    flex-flow: row wrap;
    align-items: center;
    justify-content: center;
    display: none;
}
body.aniversario-visible {
    overflow: hidden;
}
body.aniversario-visible .popunder-aniversario {
    display: flex;
} 
.popunder-aniversario-holder {
    max-width: 550px;
    position: relative;
    border: 1rem solid #094e9b;
    box-shadow: 0 0 2rem rgba(0,0,0,0.3);
}
.popunder-aniversario-button {
    position: absolute;
    bottom: 1rem;
    left: 0;
    width: 100%;
    text-align: center;
}
.popunder-aniversario-button button {
    background: #094e9b;
    color: #fff;
    border: none;
    padding: 0.8rem 1.5rem;
    font-size: 1.2rem;
    cursor: pointer;
    border-radius: 0.3rem;
}
.popunder-aniversario-close {
    position: absolute;
    background: #fff;
    border-radius: 50%;
    padding: 0.3rem;
    top: -1rem;
    right: -1rem;
    font-weight: bold;
    cursor: pointer;
}